Should Nuclear Devices Be Kept On Hand To Protect Against Near Earth Objects?

Lasrick writes: Seth Baum ponders whether nuclear devices should be kept on hand for the purpose of destroying near-Earth objects (NEOs) that pose a threat to the planet. Baum acknowledges that "The risk posed by NEOs is not zero, but it is small relative to the risk posed by nuclear weapons." Even so, Baum writes, since the consequences of an NEO hitting the earth would be catastrophic, keeping 10 or 20 nuclear devices available might be a good idea, and would be "insignificant compared to the thousands now held in military arsenals."

Comments

You mean NEOs like Russia?

[tlambert]

You mean NEOs like Russia? You can't get any nearer to Earth than that.

Probably "yes".

Re:You mean NEOs like Russia?

[MiniMike]

Near Earth Oligarchy?

Re:You mean NEOs like Russia?

[bill_mcgonigle]

You mean NEOs like Russia? You can't get any nearer to Earth than that.

+1 - humor is a great way to get at the tough issues. To put it more bluntly, though: "no, nuclear devices should be kept on hand to protect against politicians". The nuclear-armed nations have not gone to war with each other, and they won't because nuclear weapons (along with ICBM's) ensure that politicians can't simply send poor boys off to die for their lustful ambition on wealth and power without also impulsively risking their own safety.

This is unprecedented in the history of the nation state mechanism and has had major positive effects (if one considers empirical evidence rather than irrational fear). Sorry, it's not the pretty table at the UN that keeps bad leaders from misbehaving; until we can ban politicians, taking away their risk exposure would be the stupidest course of action conceivable. In the US only 5% of the population even trusts them to make sound decisions.

Maybe I should just change my .sig to "incentives matter" - the fear-mongers love to pretend otherwise, so this never stops coming up.

Re:You mean NEOs like Russia?

[garyisabusyguy]

Thanks, you really summed up my response to the submitter, which would have been along the lines of, "What makes you think that we will ever NOT have nuclear weapons?"

For the very reasons that you mention

Re:You mean NEOs like Russia?

[PopeRatzo]

The nuclear-armed nations have not gone to war with each other, and they won't because nuclear weapons (along with ICBM's) ensure that politicians can't simply send poor boys off to die for their lustful ambition on wealth and power without also impulsively risking their own safety.

Mutual Assured Destruction is based on an assumption that all politicians are rational.

You willing to bet your life on the proposition that every politician is rational?

https://en.wikipedia.org/wiki/...

Re:You mean NEOs like Russia?

[tnk1]

Strictly speaking, you don't need every politician to be rational, you just need enough that the order for insanity will be refused or serious opposition would go up. Even current nukes are not automated to the point where one man can set them off. You can be pretty sure that unless there was a serious and credible fear that the other side was going to use first, the President might go insane and attempt to launch, but you can expect the order would be refused or opposition would go up instantly if it was batshit crazy.

Other countries? Harder to say, but even a place like Iran or North Korea might not allow their leader to launch for no reason. At some level there is a circle of government where people are in the know about the realities of what is going on and would probably act to stop annihilation.

That doesn't end the risk of a nuclear war started via a build up of tensions, but there would probably be time to reflect.

Re:You mean NEOs like Russia?

[Anonymous Coward]

MAD is very much not based on the assumption that the people behind the nukes are rational. In the face of an all out attack on the USA by Russia using nuclear arms, retaliating isn't going to help the USA, and will only help to annihilate humanity. No rational person would retaliate in those circumstances - the only "gain" from doing so is to die knowing that the Ruskies get blown up as well.

So the only way to make MAD work is to make the enemy think you might just be crazy enough to hit that big red button.

Re:You mean NEOs like Russia?

[PopeRatzo]

MAD is very much not based on the assumption that the people behind the nukes are rational. In the face of an all out attack on the USA by Russia using nuclear arms, retaliating isn't going to help the USA, and will only help to annihilate humanity. No rational person would retaliate in those circumstances - the only "gain" from doing so is to die knowing that the Ruskies get blown up as well.

So the only way to make MAD work is to make the enemy think you might just be crazy enough to hit that big red button.

Read what you wrote again - slowly - and re-evaluate.

So the only way to make MAD work is to make the enemy think you might just be crazy enough to hit that big red button.

OK, if you haven't seen the fallacies and logical errors in this view yet, let me take a different approach:

ABMs, MIRVs and the Strategic Defense Initiative have made MAD utterly useless. We already have politicians and policy-makers who believe a second strike is survivable. Thus, the assurance has been removed.

Re:You mean NEOs like Russia?

[PopeRatzo]

Strictly speaking, you don't need every politician to be rational, you just need enough that the order for insanity will be refused or serious opposition would go up.

That's not how military chain-of-command works.

First, you have to assume the guy with the power to give the order to launch is rational. Then, you have to assume that someone exists in the chain of command who does not believe a second strike is survivable. Since Reagan, our foreign policy has been that survival is a possibility.

We have had presidents and very high-ranking Air Force brass who believed the world was destined to end in a biblical apocalypse that would herald the return of Jesus Christ to raise all believers to heaven. Now you're down to trusting the rational decision-making of a low-level grunt who's been stuck below-ground in a silo, watching every day for the launch order to come down. You think they train those guys to be skeptical of the orders they're given?

OK. It's funny that people who will otherwise question everything government does also have such unshakable faith in their government when it comes to A) the military and B) the police.

Re:You mean NEOs like Russia?

[houghi]

Ah, the old "It has never happend, so it never will" argument. This would work if they would make sound decisions, but they don't.

It only needs one that IS crazy enough to use them for some fake reason. Wars have been faught for fake reason for millenia. Weapons have been invented that were going to put an end to all wars.

At some point somebody will press the button. No idea who it will be. No idea if it will be a single thing or something that will escalate to the downfall of the human kind. No idea when or how, but it WILL happen.

And if you are so sure that it keeps people safe, why not give everybody some?

Re:You mean NEOs like Russia?

[tnk1]

Reagan was badly upset when he realized that the Russians actually thought that Able Archer 82 was actually a lead up to war. He got a lot more serious about arms control talks after that.

And it is not policy that use of Nuclear Weapons is survivable, the policy as of the latest Nuclear Posture Review is that the US will not guarantee no-first-use, which is not the same thing. However, we do provide that assurance for countries who have signed the NPT.

The idea is that giving a no-first-use guarantee allows the assumption that the US will accept being hit with devastating non-nuclear weaponry and not retaliate because we might not be able to retaliate in "kind" because we don't have a non-nuclear weapon that does the same amount of damage. It also is meant to allow us to maintain a credible threat against heavily militarized countries like North Korea or China without having to match them conventionally. Not providing a guarantee is not the same thing as a definite retaliation, even if something like that came to pass.

Moreover, even your fundamentalist Air Force generals are not going to launch without a reason. They may believe that they will get taken up in the Rapture, but that doesn't mean that they will start the war that kills billions of people to do it. They may be believers in an eventual apocalypse, but only truly crazy people believe that they are the ones who are meant to start it.

Don't get the idea that I feel safe with nuclear weapons around, but I don't think it is impossible for us to avoid destroying the planet with them. In any event, they are here to stay and we need to learn to live with them. I think that enough people have done the calculus in their heads about what they would do if called upon to end the world. Some military folks may perhaps be capable of a first attack out of nowhere, but even the military are not automata.

Re: You mean NEOs like Russia?

[Anonymous Coward]

Maybe. People don't react well to nuclear weapons and that's a good thing. Look, we did worse in terms of damage and loss of life than the two nukes we used in WW2 with conventional weapons in both Germany and Japan, but that's what is remembered. (Rightly so, but Dresden and Tokyo should be remembered too).

We've had all kinds of false flag or at least questionable operations pulled on us, including 9/11, yet the evil people who do those things have never used nukes even though they very likely could have. I think they're afraid they won't be able to control people's reactions. Whatever the reason, we're doing well in that regard at least. So maybe we won't get that button pushed. I hope not anyway.

Re:You mean NEOs like Russia?

[Immerman]

It appears you fail to realize that even total mutual annihilation of US and Russia would leave the large majority of humanity untouched by the "first wave" damage. In fact with a little luck those south of the equator wouldn't even have to deal with too terribly devastating levels of fallout. Now if China got into the fracas as well things would start looking a lot worse, but still - even if every major military power on the planet totally annihilated each other there'd still be lots of humans left to struggle through the fallout. You could wipe 80% of the human species overnight and there would *still* be more people around than there were at the turn of the last century.

That being the case, retaliation doesn't dramatically increase the chances of human extinction - it just makes sure that the people who killed you aren't included among the survivors.

Re: You mean NEOs like Russia?

[Anonymous Coward]

Likely could have? Do you have any idea how hard it is to deliver a nuclear warhead large enough to do any real damage?

A dirty bomb is at least plausible.

Re:You mean NEOs like Russia?

[rtb61]

Radiation and mutational evolution go really well together. So a global war will pretty much guarantee those at the simplest end of the evolutionary path, bacteria and viruses will tend to leap ahead (numbers are on their side, seriously on their side) means that a major planetary extinct will soccer and only the simplest organism will survive as they are evolutionary able to keep up with short life cycles and high numbers. There is simply huge mass of vary toxic materials in cities that simply should not be burnt and released into the atmosphere.

So a real extinction race, nuclear winter, nuclear radiation, released pollution toxins and bacterial and virus evolution ahead of much more slowly evolving complex species. Yeah, we would be fucked.

Back to meteors, if you need to do it in a desperate hurry it might be better to do nothing, because one meteor whilst still hugely destructive might be better than a radio active dust cloud on the same course. Still with proper planning and preparation, there is something very worthwhile about a astronomical impact defence, like our continued survival as a society and as a species.

Re:You mean NEOs like Russia?

[davester666]

We have to put Bruce Willis in cryostasis right now if we want to have any chance of properly positioning the warheads inside the NEO when the time comes.

Re:You mean NEOs like Russia?

[Xyrus]

All joking aside, nuclear missiles will do precisely dick to any incoming impactor that could threaten even a city. A 1 km wide nickel-iron asteroid traveling at a typical impactor's velocity would yield about 60,000 megatons. Throwing a handful of nukes at it would be about as effective as throwing pebbles at a tank.

Re:You mean NEOs like Russia?

[Anonymous Coward]

Moreover, even your fundamentalist Air Force generals are not going to launch without a reason.

Chain of command is a reason. Mental illness is a reason. Religion is a reason. Human error is a reason. There are plenty of reasons to think that nuclear weapons are a continuing danger to our safety. Whether they are more or less dangerous than the threats of disease or climate change is another debate.

Re:You mean NEOs like Russia?

[Stuarticus]

Of course, that's why the Vietnam war never happened.

Re:You mean NEOs like Russia?

[tlambert]

Chain of command is a reason. Mental illness is a reason. Religion is a reason. Human error is a reason. There are plenty of reasons to think that nuclear weapons are a continuing danger to our safety. Whether they are more or less dangerous than the threats of disease or climate change is another debate.

Anti-nuclear nuts out to prove that nukes are dangerous by setting one off to prove their point ... is a reason.

Re:You mean NEOs like Russia?

[Joce640k]

keeping 10 or 20 nuclear devices available might be a good idea, and would be "insignificant compared to the thousands now held in military arsenals."

He's referring to non-military, privately-held nuclear weapons.

Obviously the answer is "yes", we should definitely have a few dozen of those. Just in case.

Re:You mean NEOs like Russia?

[Anonymous Coward]

It hasn't happened in 60 years so it won't happen?

A catastrophic NEO hasn't occurred over that time-frame either. 30 years and a handful of nations is a very very small sample set from which to draw the conclusion that nuclear weapons make the world safer. It would only take one modern-day Genghis Khan to blow that theory to pieces.

Re:You mean NEOs like Russia?

[Immerman]

Microbes get tens of thousands of generations for our every one, and often more unstable DNA as well - they already have the massive evolutionary advantage. Slow-breeding complex life likely only survives thanks to our symbiosis with some of them. We're only just beginning to understand just how much of "our" immune system isn't actually genetically related to us.

Re:You mean NEOs like Russia?

[Maury Markowitz]

> This is unprecedented in the history of the nation state mechanism ::rolleyes::

You really need to read more history. You might want to start with Pax Romana and the late 19th century, to name two.

All the nukes did was make us fight proxy wars instead. Ask Korea, Angola, Vietnam, and Afghanistan how much they enjoyed this unprecedented period of peace.

Re:You mean NEOs like Russia?

[Maury Markowitz]

> Throwing a handful of nukes at it would be about as effective as throwing pebbles at a tank

Plus we have no way to deliver it.

Re:You mean NEOs like Russia?

[PopeRatzo]

Reagan was badly upset when he realized that the Russians actually thought that Able Archer 82

By the time Reagan said "the bombing will start in 5 minutes", he was already half-senile and going potty in a diaper.

You give too much credit to figure heads. They've been fucking up the world for centuries. You think because it's "modern times" that all of a sudden they're any less monomaniacal, egotistical, narcissistic or in the case of Reagan, just plain crazy evil?

I think that enough people have done the calculus in their heads about what they would do if called upon to end the world.

So why can't they do "the calculus" when it comes to the threat of climate change?

 

Re:You mean NEOs like Russia?

[Echo_Hotel]

Isn't that the plot to one of the Metal Gear games?

Effect of nukes on NEOs

[maroberts]

Have you seen how much effect a nuke is likely to have on a significantly sized NEO? None whatso fucking ever. If an NEO is enough to wipe us out, it won't be screwed by a nuke.

Also the ideal launch point for such a nuke would be from space, not Earth.

Re:Effect of nukes on NEOs

[Spazmania]

Yeah, the idea is idiotic. You blow up the NEO. Wonderful. The million pieces still have the same mass, velocity and therefore kinetic energy heading towards the planet.

You don't blow up threatening space objects. Space is really big. All you do is give the object a little nudge while it's still far enough away. The little nudge is all it takes to miss the planet by a very large margin.

Re:Effect of nukes on NEOs

[XxtraLarGe]

Have you seen how much effect a nuke is likely to have on a significantly sized NEO? If an NEO is enough to wipe us out, it won't be screwed by a nuke.

Wouldn't that depend on whether or not we sent up a crew of oil rig drill operators to drill into the NEO first, before inserting the nuke?

Re:Effect of nukes on NEOs

[Tuidjy]

Yeah, and I think that the danger from any NEO that is small enough to be affected by those space based nukes is way, way, WAY less than the danger from space based nukes that can be seized, one way or another, by some nutcase... leaving aside the fact that those who thinks they are a good idea in the first place are nutbags themselves.

Re:Effect of nukes on NEOs

[RavenLrD20k]

Also the ideal launch point for such a nuke would be from space, not Earth.

So are you saying...nuke it from orbit?

We could nuke it from orbit with enough nukes that the NEO trajectory could be adjusted to come into earth orbit. Essentially we could nuke it into orbit from orbit to nuke it repeatedly while it orbits, dawg!

One last one... That's no Moon! That's a NEO...it really is the One! Just call it Mr. Anderson.

Re:Effect of nukes on NEOs

[pr0t0]

Agreed. The question the article poses presupposes that nuclear devices CAN protect against NEOs. Most research in the field answers the question with a resounding "no". The best use of a nuclear weapon against a NEO would be to detonate several, in succession, to slightly alter the course of the NEO or to change its velocity. But as maroberts intimated, this would have to be done at a significant distance from Earth...probably near or past Jupiter's orbit at a minimum.

Re:Effect of nukes on NEOs

[Dunbal]

Most of the damage from a nuclear weapon comes from the overpressure created by superheated air. There's no air in space. So apart from being hit by tiny fragments of bomb casing and part of the object being heated a little not much would happen, even if detonated on the surface of such an object. Drilling into it on the other hand might - MIGHT work. Now, how'd you like to drill a couple hundred feet into solid iron-nickel alloy?

Re:Effect of nukes on NEOs

[Moses48]

The summary is wrong. TFA says the nuke would be for changing the trajectory of the NEO, not destroy the NEO. It also found nukes to be better than other methods of changing trajectories.

Re:Effect of nukes on NEOs

[g0tai]

Many more pieces, with a lot more surface area to:

1) burn up with.
2) decelerate with.

One big problem becomes less significant the smaller it gets.

Re:Effect of nukes on NEOs

[LWATCDR]

Actually no it is not.
You do not try and blow up the NEO. You try and deflect it. The idea is that you use the "shaped" nuclear charge design developed for the Orion.
The NEO becomes the pusher plate and you nudge it so that it does not hit the earth.

Re:Effect of nukes on NEOs

[sverdlichenko]

Same hit spread over entire hemisphere probably would be much less catastrophic: small objects will burn in atmosphere instead of bringing their kinetic energy down to earth. We can hope for a hot summer instead of tsunami followed by a long "dust winter". The problem is how to blow up this NEO to the small enough pieces.

Given our nuclear stockpiles, I'd rather build big enough Orion spacecraft and just ram the thing. It may be enough to make it miss if hit early enough. Earth is quite small and fast moving target after all.

Re:Effect of nukes on NEOs

[sverdlichenko]

With a NUCLEAR DRILL!

Re:Effect of nukes on NEOs

[spiritplumber]

I'd imagine that a surface detonation on an asteroid would cause enough mass to leave the asteroid, directionally, to nudge the rest away.

Re:Effect of nukes on NEOs

[Anonymous Coward]

That is outright incorrect. Teller-Ulam fusion bombs can be scaled up to arbitrarily large sizes (http://blog.nuclearsecrecy.com/2012/09/12/in-search-of-a-bigger-boom/) and can be detonated at the appropriate location to divert the NEO. The idea was never to completely vaporize the NEO, but rather to create enough thrust on its surface to change the orbit so that it misses Earth. Further, a Tsar Bomba-sized weapon is likely plenty to accomplish this task (http://www.wired.com/2012/03/mit-saves-the-world-project-icarus-1967/). And large bombs aren't even necessary. A more effective approach would be to use a large number of smaller nuclear devices to precisely change the orbit. You can deliver many Tsar Bomba's worth of energy with the arsenal present in a US or Russian nuclear missile sub.

And yes, space-based defenses are the ideal for this application. However, they are outlawed by international treaty.

The real challenge here is early detection. Since building the above defense system is politically difficult in the current international political environment, sufficient warning is necessary to allow the US and Russia to put together a joint mission. It would likely require dozens of launches and hundreds of warheads to ensure NEO diversion with a sufficiently high probability.

Re:Effect of nukes on NEOs

[Talderas]

Only if space madness is a factor and Bruce Willis leads the team. Otherwise we're proper fucked.

Re:Effect of nukes on NEOs

[AK Marc]

The impact of a large NEO is in the energy being imparted to the planet surface, ejecting additional material, earthquakes, tsunamis and other impact artifacts. The "damage" from heating of the air on entry is inconsequential. So spreading the entry to millions of small pieces that burn up in the atmosphere is a better outcome.

Re:Effect of nukes on NEOs

[burtosis]

Actually that's the entire point. Sure movies have it dead wrong. But the general idea is to gently boil off material over the entire side giving it a small kick. Several would be needed in all likelihood and hopefully at least one orbit ahead of time. At the very least several AU of distance would be needed.

There are much better ways of handling it though and the insignificant chance of a deadly object we can deflect with that method is likely dwarfed with the chance of incompetence and mishandling.

Simply drilling into it and fragmenting it would be disastrous at close range, perhaps even makng it more deadly and is as likely to completely reduce it to dust as exploding a whale with tons of dynamite.

Re:Effect of nukes on NEOs

[Anonymous Coward]

1) burn up with.

And where do they burn up? In the atmosphere.
So where does the heat go? Into the atmosphere.

Great, you've just incinerated an entire hemisphere at a mere 600 degrees rather than a single point at a few thousand.

And since heat loss by radiation is proportional to the third power of the temperature, you've just made it take a lot longer to cool off.

Yay.

Re:Effect of nukes on NEOs

[ckatko]

While on a practical sense you may be right, the idea that they'll have the same velocity is completely false.

That's like saying detonating TNT in front of a semi-truck on the highway means it'll fly the same speed in another direction. Or that it'll move in the same direction it once was. Or if you detonated TNT in the water near a ship, it'd still go the exact same direction.

Where a near-earth object goes after being hit by, or being nearby, a large explosion is entirely dependent on the position and composition of the objects. But one thing that will absolutely not happen is them magically going the same direction they were.

Re:Effect of nukes on NEOs

[Anonymous Coward]

Yeah, the idea is idiotic. You blow up the NEO

Like you blow up an iceberg. Which of course doesn't work at all. And then you have rocks in SPACE without atmosphere. So what will a bomb do? A bomb, that is designed to work in an atmosphere to damage things with pressure gradient ??

Right.

No "blow up into little bits". It would most likely do absolutely nothing.

Re:Effect of nukes on NEOs

[Moses48]

The article quotes a NASA study from 2007 on the best way to "deflecting NEOs". They found nuclear devices to be "10-100 times more effective than the non-nuclear alternatives analyzed in this study." You are actually saying what the article is saying. The article doesn't say the nukes are to explode the NEO, leave it to Slashdot to have a misleading summary.

Re:Effect of nukes on NEOs

[phantomfive]

I agree with your point, clicked on the link figuring it was medium.com or something, but no, it was The Bulletin of Atomic Scientists.

Really? They should have known better. Atomic scientists have really gone downhill from the days of Von Neumann and Feynman.

Re:Effect of nukes on NEOs

[Smidge204]

Roughly 4 out of 5 asteroids are Chondrites - basically giant piles of fused gravel. Nickel-iron asteroids only account for ~5% of known bodies.

Of course, breaking up an asteroid will not help if you don't deflect a significant portion of the mass. 40 million tons of stuff traveling at thousands of kilometers per second carries a certain amount of energy, and that energy isn't going to go away just because you break it up into 40 million 1-ton bits.
=Smidge=

Re:Effect of nukes on NEOs

[TheCarp]

This. Ideally you see it with plenty of warning so that you have time to deflect it. Shit maybe you use multiple nukes over the course of a week or two to nudge it into a safer flyby, possibly even one that impacts the moon (for 10 billion bonus points), or flings it off onto a path that will not meet up with us again.

Shit should make an x-prize contest out of asteroid snooker. Prize to the company that demonstrates the capability to take an NEO, and deflect its flyby by an amount which would prove ability to deflect a real hit of appropriate size. Must use no more than N nuclear weapons (obviously the sponsoring nation would have to handle the launch and deployment phases).

Object Must not do another flyby of earth for another 200 years minimum.

Extra points for designs using existing warheads that can be easily repurposed.

Extra points for never having another flyby (solar escape, capture by another planet, non-intersecting orbit, etc all valid end states)

Make it do a grand tour of the solar system, and dump into the sun: Lead engineer gets a state renamed after him.

Re:Effect of nukes on NEOs

[Kjella]

You don't blow up threatening space objects. Space is really big. All you do is give the object a little nudge while it's still far enough away.

Of course a "little nudge" is relative if you're talking objects of any serious consequence. A 100m asteroid - a decently sized H-bomb on impact - is likely to weigh >1,000,000 kg. That's a lot of inertia to nudge even a little bit. The smallest ones (<15m) we don't need to do something about, the biggest ones we can't do anything about (the dino killer was a trillion tons) so there's a few in the middle that we maybe could, but statistically it's like an entire city struck by lightning - nasty death from above for those it happen to, not really a threat to the human race.

Re:Effect of nukes on NEOs

[Urkki]

A meteorite which does not create a big crater will throw a lot less stuff up into the atmosphere, and will have much less global consequences. Getting a shower of smaller pieces would not be fun, but a single big impact penetrating deep into the crust with equal energy is worse.

Re:Effect of nukes on NEOs

[The Grim Reefer]

Have you seen how much effect a nuke is likely to have on a significantly sized NEO?

What are you talking about? Bruce Willis and Michael Clarke Duncan can drill a hole and split an asteroid with a nuke so perfectly that, even if it's between the earth and the moon, both halves will miss...

Oh, wait. We're in trouble.

Re:Effect of nukes on NEOs

[Anonymous Coward]

but a nuke might have enough energy to "push" it out of the way, you don't even need to explode the nuke on the surface of the NEO, but directly in front of it or behind it, giving it a nudge via the force of the explosion to make it's orbit slightly off kilter pushing its orbit from intercepting the earth. now in reality that opens it up to all kinds of other problems with where it is going to go, it might delay it only a year or two... or it could delay it significantly. there needs to be all kinds of complex maths done to figure all that out. I don't have numbers to even begin to do the math.

Re:Effect of nukes on NEOs

[njnnja]

RTFA They specifically look at a standoff explosion versus a surface or subsurface explosion and prefer the standoff explosion precisely because they are aware of the possibility of blowing something up with a nuclear weapon. Amazingly enough, the professional rocket scientists at NASA actually considered the consequences of the alternative tactics before making their recommendation

Re: Effect of nukes on NEOs

[ArmoredDragon]

If you blow up an object, I very much doubt that all of its pieces are still going to hit you. Some of them will go in the opposite direction, some will land in a slowly decaying orbit, and very few of them are likely to continue on their existing trajectory, and the few that do will have their kinetic energy reduced.

That's assuming that the nuke actually blows it up. Nukes are FAR less effective in space because there's no atmosphere for the thermal energy to create a big shockwave, and there's no solid ground beneath it to amplify the intended direction of said shockwave.

IMO if you want to blow up an NEO, you'll probably want some kind of kinetic weapon akin to a giant bullet, maybe a space born railgun or something.

Still though, nudging is probably a better approach.

Re:Effect of nukes on NEOs

[Anonymous Coward]

Harry Stamper: I have been drilling holes in the earth for 30 years. And I have never, NEVER missed a depth that I have aimed for. And by God, I am not gonna miss this one, I will make 800 feet.
Chick: 42 seconds.
Harry Stamper: But I can't do it alone, Colonel. I need your help.
Colonel William Sharp: Do you swear on your daughter's life, on my family's, that you can hit that mark?
Harry Stamper: I will make 800 feet. I swear to God I will.
Colonel William Sharp: Then let's turn this bomb off.

Re:Effect of nukes on NEOs

[ShanghaiBill]

And where do they burn up? In the atmosphere.

No. First, the goal is to deflect it, not "blow it up". We have mapped out many, many thousands of NEOs, so if we find a "big one" that is likely to hit earth, we will probably have years of warning. Over that time frame, even a small nuke can easily change the course enough to miss earth. Heck, even a non-nuke kinetic energy hit would likely be enough. Second, even if we do blow it up, the chunks will spread out, and most of the pieces will miss earth entirely. Third, if they hit the atmosphere, and burn up, you only have the dust and debris from the NEO itself. If it impacts intact, it will throw up far more terrestrial material than just its own mass.

Personal opinion: I think building nukes to stop NEOs is really dumb. It would be far better to spend the resources on detection, and exploration of the solar system. We should only build a nuke if we find an NEO with our name on it. There will be plenty of time if we focus on detection.

Re:Effect of nukes on NEOs

[garyisabusyguy]

You are assuming that the object is solid enough to be nudged from a single point

I would much rather that we look into splattering it with a bunch of white material

This will significantly alter the pressure that it receives from the sun and deflect every single piece of it that you can get 'paint' on

Re:Effect of nukes on NEOs

[Anonymous Coward]

A nuke can level a city -- we're talking killing 30 million people, maximum.
An asteroid can level a planet -- 7 billion people and all their pets.

Re:Effect of nukes on NEOs

[Anonymous Coward]

NOPE. If something is 600 degrees, it will takes the same time to cool as the 3000 degree thing will AFTER it cools to 600 degrees. Valid statement for any definition of degrees related to temperature.

Re:Effect of nukes on NEOs

[eth1]

Yeah, the idea is idiotic. You blow up the NEO. Wonderful. The million pieces still have the same mass, velocity and therefore kinetic energy heading towards the planet.

You don't blow up threatening space objects. Space is really big. All you do is give the object a little nudge while it's still far enough away. The little nudge is all it takes to miss the planet by a very large margin.

OK, I'm going to stand 50 meters away from you and shoot you with a shotgun. I'll give you a choice: would you prefer me to use a slug, or an equivalent mass of birdshot?

Also, blow it up far enough away, and the center of mass of the object could pass right through Earth without any of the bits actually hitting us.

Re:Effect of nukes on NEOs

[PopeRatzo]

You blow up the NEO. Wonderful. The million pieces still have the same mass, velocity and therefore kinetic energy heading towards the planet.

And now all those pieces are radioactive to boot.

I've read some cockamamie arguments from people who are desperate to make sure we keep our nuclear weapons, but this one is a real hoot.

Re:Effect of nukes on NEOs

[LWATCDR]

Should be no issue for a stone or nickel iron asteroid. Even for an ice or carbonaceous a series of smaller devices should not "shatter" one.
"I would much rather that we look into splattering it with a bunch of white material"
You would probably find the total mass needed would be very large compared to nuclear devices for the same total effect.
a B61 is less than 700 lbs and can produce 600kt yield.
a W32 is less than 70lbs can can yield 250t.

Re:Effect of nukes on NEOs

[BitZtream]

And you, like most people missed the point.

If you have one rock hit, all its energy is concentrated. The atmosphere isn't going to slow it down as much as it will collectively slow down 'millions'

With millions, some of them ARE going to miss the planet, and some will be vaporized by the blasts in space, there you've already lowered the total energy involved with hitting earth. Not much possibly, but some.

Would you rather a hail ball the size of a golf ball hit your house, and one each hitting every house in your city ... Or would you prefer that a Volvo of ice fell on it, because that's what your suggesting.

As with basic impact physics if you want to lower the damage spread out the impact surface area and time. If the NEO is large enough that in a million bits, it still causes global catastrophe then it's still going to be a global catastrophe as one rock, and it's going to be worse.

The blast will break it into a million peices that are ALLnow on a new course. If you do it at any distance of any magnitude from earth, the new course will be a completely different path that is not in ours.

Contrary to all the stupid shit you've heard from "scientists" about how bad it would be, that's only true if IT WAS ALREADY TOO LATE TO DO ANYTHING.

Under no condition does it actually get worse on a global scale.

Re:Effect of nukes on NEOs

[Anonymous Coward]

I once read all it would really take (provided we caught it in time) would be to paint one side of the NEO white and the other black and that would push its path away from Earth. Why am I not reading more about deep space painting experiments?

Re: Effect of nukes on NEOs

[Anonymous Coward]

The actual thermal effect of a nuclear weapon in the atmosphere is almost exclusively due to the fact that there is an atmosphere. In the immediate milliseconds following fission you get a very intense burst of soft x-rays, these are in turn absorbed in the first 2 miles or so of the atmosphere, superheating its component gases and causing it to radiate white, IR, and UV light. FUMP. This emitted IR/UV/White is the intensity that causes flash fires, vaporization, deflagration, etc.

In a vacuum, a nuke goes off like a _very_ short flash bulb followed by a rapidly expanding cloud of _very_ whispy very superheated plasma that is composed of the nuke's fomer mass - only. What you don't see however is that the intense surge of X-rays does not get captured by anything, and instead continue on, rather lethally for hundreds to thousands of kilometers.

A nuke against a NEO would best be used well ahead of time, in close proximity of 5 to .2 kilometers depending on the item's composition. Upon detonation the x-ray burst would get captured by the first few centimeters of the objects surface material facing the nuke. Material would boil off to several mm of depth, almost explosively for a few fractions of a second, and deliver a soft shove to the object conversely away from its boiled off char.

Re:Effect of nukes on NEOs

[Anonymous Coward]

Which would you like to get hit with, a fist sized rock, or a fist sized lump of sand?

Re:Effect of nukes on NEOs

[Anonymous Coward]

First they have to separate... by several miles. Otherwise they just come through as a single object.

Yes, the lead objects might burn up... but the ones following it won't as they have had the path opened up by the lead object.

Re: Effect of nukes on NEOs

[Anonymous Coward]

The only way some will "go in the opposite direction" is if you blow it up at the center, not the leading edge.

Re:Effect of nukes on NEOs

[Anonymous Coward]

Actually nukes in space have no air to soak up their voluminous amount of x-rays and produce the ensuing white hot sustained 2 mile circumferential ball of IR/UV/Whitelight firey death. Instead the xrays continue on to wherever. If you popped one next to an asteroid, the xrays would heat and vaporize the first few mm worth of material on the surface of the asteroid facing, giving a soft shove in the opposite direction.

you could slightly juice this up with spraying the asteroid with some high- H material such as oil or wrapping it in saran wrap. I'm not kidding either.

Re:Effect of nukes on NEOs

[tnk1]

You will be less likely to have a nuclear winter in that scenario, but something that hits with a gigaton of energy in one piece, is still going to release a gigaton, only over a larger area. It may not create a crater, but you'll probably have pretty much all the vegetation (and people) go up in smoke before the fireballs hit the ground. Lighting a continent on fire may be almost as bad as a direct impact. In fact it may be worse.

The US changed from using huge megaton warheads on it's nuclear missiles because you actually get more effect from more, but smaller warheads which impact in a wider area. You're still dropping a few megatons per ICBM, but more surface area is affected.

Re: Effect of nukes on NEOs

[Ichijo]

Nukes are FAR less effective in space because there's no atmosphere for the thermal energy to create a big shockwave, and there's no solid ground beneath it to amplify the intended direction of said shockwave.

So there's nothing for the explosion to push up against (Newton's Third Law). That makes sense.

IMO if you want to blow up an NEO, you'll probably want some kind of kinetic weapon akin to a giant bullet, maybe a space born railgun or something.

What's that going to push up against?

Re:Effect of nukes on NEOs

[Anonymous Coward]

I'd imagine that a surface detonation on an asteroid would cause enough mass to leave the asteroid, directionally, to nudge the rest away.

Why would you think that? Since there's no dense atmosphere to super heat, so there's no real shock wave to "frack" the surface apart. You're going to get a little bit of vaporized matter - 10-20kg, tops 100kg for a large device, but that will just re-orbit itself if the object has any real mass, resuming the original trajectory. Plus 20kg of plutonium or whatever's fallout of cesium, strontium and other nastiness.

Basically, anything big enough to be scary is too big to divert with a nuke unless we find it years ahead of time. We've mapped, what, 1% of the sky in terms of annual cometary like debris? Anything small enough to hit with a nuke is probably less dangerous than a nuke, unless it's known to hit a super dense city.

If we are seeing thing years ahead of time, we're better off throwing rocks at it and hoping for a poll cue ball style deflection. So sure, fire a rocket at it, but the payload can be an inert iron mass. Spend 99% on detection, at least until we find something. Otherwise the thing we don't see will take out the rocket defense base right before we find the big one coming behind it :p

Re:Effect of nukes on NEOs

[Nukenbar]

Maybe the nuclear blast is the little nudge for a big enough object.

Re: Effect of nukes on NEOs

[Coren22]

You are far better detonating the nuclear weapon above the side of the NEO to cause outgassing/ablation which will push the NEO off course so it likely will miss the Earth.

Big kinetic hits won't help anywhere near as much.

Re:Effect of nukes on NEOs

[Coren22]

Heck, attaching a nuclear powered ion engine would work way better than a nuclear weapon. You might even be able to do a capture and use the NEO as orbital materials.

Re:Effect of nukes on NEOs

[khallow]

If you popped one next to an asteroid, the xrays would heat and vaporize the first few mm worth of material on the surface of the asteroid facing, giving a soft shove in the opposite direction.

I'd say tens of meters, not millimeters. X-rays penetrate quite well and the upper layers of your asteroid would have absorbed almost half the energy of a nearby detonation.

you could slightly juice this up with spraying the asteroid with some high- H material such as oil or wrapping it in saran wrap. I'm not kidding either.

You need density not "high-H" to stop x rays.

Re:Effect of nukes on NEOs

[Anonymous Coward]

A little nudge? You mean like the little nudge that would be given by setting off a nuke near it?

Re: Effect of nukes on NEOs

[ArmoredDragon]

The idea being a rail gun gains its kinetic energy from magnetism, colliding with the object. I guess a more appropriate term is to shatter it rather than blow it up, but since it's in space there's not much of a visual distinction.

Re:Effect of nukes on NEOs

[dsmatthews9379]

>Also the ideal launch point for such a nuke would be from space, not Earth.

And that is the catch they try to get your consent for, after you naively agree to the first idea.

I can't see how there is any way around the fact that anything powerful enough to deal with a NEO, rapidly, can also be used to destroy an entire country on Earth.

I would consent to a large nuclear powered spaceship being kept at L4 https://en.wikipedia.org/?titl... so that it could have enough time to match the velocity of a NEO then attach to it for the purpose of accelerating inward toward the sun to be destroyed.

Re: Effect of nukes on NEOs

[ArmoredDragon]

The comment about kinetic energy is assuming you want to shatter it into many pieces instead of changing its course, which I don't believe a nuke can do, unless Bruce Willis drills a hole in it.

Re:Effect of nukes on NEOs

[Anonymous Coward]

This is one are where theoretical physics trumps "common sense" E(k)=mv^2 /2. You know how much an exlosion will change the velocity of an asteriod travelling 30,000 mph? - NOT ENOUGH. If you don't believe me, just convert to metric units. Somehow Slashdot folks tend to believe things that have a decimal point.

Re: Effect of nukes on NEOs

[ArmoredDragon]

Ooh and as for what holds the radio gun in place... Dunno, the moon perhaps? Or we don't really care where it ends up after we use it, but that costs half of its kinetic energy.

Re:Effect of nukes on NEOs

[blazer1024]

I thought you send a team of oil rig workers (the only people on earth who know how to use a drill) instead of astronauts up to the object, drill inside, sacrifice themselves to detonate the thing "manually", split the object in two so that each piece falls into the ocean, and then outrun the resulting tsunami by running up a hill.

Man... just when you start trusting Hollywood.

Re:Effect of nukes on NEOs

[Anonymous Coward]

Exactly. One large object can punch through the atmosphere and reach the surface. A fleet of smaller objects, even if they have exactly the same mass, poses a much reduced threat. And once you have broken up a large NEO chances are, some of those fragments will miss Earth entirely.

If the GP's point was that many smaller objects still pose some threat, well then yes. Breaking up the NEO with explosives is highly uncertain. You don't have much control over the size or number of the resulting fragment mass. Individual pieces may well still be too big to achieve safety. And if the objective was to change the trajectory to miss the Earth, well that might not work either.

In the end your choice is simple: Do you attempt to do something to save yourself and the Earth, or not? I'm pretty sure we would make the attempt.

Re: Effect of nukes on NEOs

[Rei]

More than that not all of it hits you is that it doesn't all hit you at the same time. Earth has a massive radiative surface area; any delays between deposits of energy are hugely important.

Anyway, the AC who replied first got it exactly right. Nuclear weapons in space are X-ray weapons that deliver force by boiling away the surfaces of objects (even at a distance). Not only is there an immediate direct effect from the boiling off of mass, but you're also creating a coma around the object which will also have an effect by increasing the force of the solar wind on it. It's like giving the object a magnetic sail.

Redirection really isn't inconceivable.... given enough time. But "time" is really the key issue. You're not going to redirect a large asteroid days before impact. But years in advance, that's quite doable for reasonable sized bodies.

Re:Effect of nukes on NEOs

[Rei]

What sort of nuclear engine are you envisioning that would match the thrust of bombs boiling off the asteroid's surface in a big plasma wave?

Anyway, as for the question at hand, there's an obvious solution: design and build nuclear bombs for the purpose that would make terrible weapons. Make them way too big to fit on ICBMs, requiring giant, easy to target, support infrastructure-heavy boosters to get into space. Which of course, when you're talking about NEOs, you want "huge" anyway, Tsar Bomba or bigger in size. Effective weapons against Earth targets are much smaller, hundreds of kilotonnes to a few megatonnes in MIRV configruation. Deflection devices would just be massive layer-cake Teller-Ulam systems.

Anyway, detection is top priority. Construction and testing of deflection prototypes is second priority. As for whether we should keep things on hand, if we have a good enough detection network, that may not be necessary - it may be enough simply to have a tested design on hand that we could build and field in a few years' time if there came a need.

Re:Effect of nukes on NEOs

[painandgreed]

Most of the damage from a nuclear weapon comes from the overpressure created by superheated air. There's no air in space. So apart from being hit by tiny fragments of bomb casing and part of the object being heated a little not much would happen, even if detonated on the surface of such an object. Drilling into it on the other hand might - MIGHT work. Now, how'd you like to drill a couple hundred feet into solid iron-nickel alloy?

It's possible to make a kinetic weapon out of a nuclear bomb. The principle is similar to a hydrogen bomb, but instead of surrounding the initial atomic bomb with an x-ray reflective shell to focus them on hydrogen to cause intense pressure and cause fusion, the x-rays are instead focused in a single direction at an x-ray absorbing material. This material is turned into a plasma traveling in a relativistic speed in the intended direction where it will slam into and impart its energy to a desired target. Originally designed for space combat, it hasn't been tested, but is pretty simple in theory.

Re:Effect of nukes on NEOs

[JimSadler]

I wonder if we have the ability to actually change the flight path of a serious threat sized object in space. If we were that good at planing and delivery we would all be wonderful pool players. But so many of us scratch on the eight ball despite our credentials.

Re:Effect of nukes on NEOs

[kellymcdonald78]

Or to put it another way (to more accurately reflect the energies involved), would you rather be hit in the arm by a 30mm round (taking your arm off), or hit by several dozen 9mm rounds. The problem isn't the impact, its all the kinetic energy needs to go somewhere. Either into the Earth which vaporizes rock and spreads it around, or in the atmosphere that flash cooks the hemisphere

Re:Effect of nukes on NEOs

[kellymcdonald78]

No, because those millions of small pieces release the same amount of energy into the Earth system, just now into the atmosphere now rather than the planet surface. Rather than ejecting material, earthquakes, tsunamis, you flash fry the hemisphere.

Re:Effect of nukes on NEOs

[kellymcdonald78]

Just how big of a nuke do you think we have? A 1km stony asteroid has a gravitational binding energy equivalent of a 500 megaton bomb (i.e. you would need a bomb 10 times bigger than the largest ever built to blow up a 1km asteroid, assuming 100% of the energy was absorbed into the structure of the asteroid) A question, would you prefer getting hit in the arm with a 30mm round (losing your arm) or several dozen 9mm rounds,

Re:Effect of nukes on NEOs

[DamnOregonian]

Come on, now.
Your second sentence is certainly correct, however, your first couldn't be more wrong in its conclusion.

Which would you rather be hit with? A ~150J .22LR round, or a ~320J baseball?
Contact area of the kinetic energy matters. The atmosphere is going to do a great job of absorbing nearly ALL of the kinetic energy of a large impactor, if you can reduce it to small enough rubble, while it isn't going to do shit against a big dense bolide with a minimal contact area.

I'll take atmospheric buck shot over a .50 cal any day.

Re:Effect of nukes on NEOs

[DamnOregonian]

A gigaton of energy spread over the entire face of the Earth isn't as bad as you make it sound.

It's about 2T/km^2. It might be fun to watch, it might even raise temps a bit, but we're not going to all incinerate in hellfire.

Re:Effect of nukes on NEOs

[AK Marc]

The temperature increase isn't that much. Go on, calculate it if you like.

Re: Effect of nukes on NEOs

[DamnOregonian]

Some of them will go in the opposite direction

Unlikely. This isn't a stationary object, and the velocity of it is almost stupid. Sure you'll slow a lot of pieces down a lot, but I sincerely doubt you'll reverse their trajectory.

That's assuming that the nuke actually blows it up. Nukes are FAR less effective in space because there's no atmosphere for the thermal energy to create a big shockwave, and there's no solid ground beneath it to amplify the intended direction of said shockwave.

That's ok, rock absorbs high energy photons and neutrons even better than air. The shockwave of a nuke causes the serious damage away from the fireball, but I assure you the people within the area of atmospheric ignition due to high-energy radiation couldn't give two squirts of piss about the pressure of the atmosphere there. Definitely detonate close to the bolide.

IMO if you want to blow up an NEO, you'll probably want some kind of kinetic weapon akin to a giant bullet, maybe a space born railgun or something.

You could be right... But I doubt it. Someone would have to do the math to see what portion of the energy output of a large hydrogen bomb would hit the object, how much the object would absorb, and how it would react to the incidental heating. (my guess is very traumatic explosion of the object itself)

Still though, nudging is probably a better approach.

I think we all agree here

Re:Effect of nukes on NEOs

[golodh]

@Maroberts

Nonsense on both counts.

From the article: nuclear explosions are 10 to 100 times as effective against asteroids on collision course as any other means investigated.

Besides, it really doesn't matter where you launch an nuke that you're about to detonate near an asteroid from, as long as it gets there. There is almost no time difference in delivery time (time to exit the atmosphere is less than an hour).

Re:Effect of nukes on NEOs

[Anonymous Coward]

I was told that H-bombs would vaporize mountains and even a direct hit would take out NORAD. In comparison, a 100m rock seems small. The soviets ha the AN602.

Re: Effect of nukes on NEOs

[mmell]

How will drilling a hole in a nuclear device help?

Re: Effect of nukes on NEOs

[ArmoredDragon]

It helps it see where it's going.

Re: Effect of nukes on NEOs

[Wycliffe]

That's assuming that the nuke actually blows it up. Nukes are FAR less effective in space because there's no atmosphere for the thermal energy to create a big shockwave, and there's no solid ground beneath it to amplify the intended direction of said shockwave.

Still though, nudging is probably a better approach.

The assumption everyone is making is that you would use a nuke to blow up the NEO. I would think it would make more sense to use the nuke to "nudge" the NEO. If you place or fire the nuke at the side facing earth (or the side opposite the direction you want it to go if that's different) then when it detonates it should blast the NEO in the opposite direction. We've already thought of doing this with spaceships which basically propel themself forward by firing nukes out the back. This seems like it would be the simplest way to move the NEO. Staying in one piece would actually be preferred with breaking up being the less desirable but hopefully still improved situation.

Re:Effect of nukes on NEOs

[Wycliffe]

Or to put it another way (to more accurately reflect the energies involved), would you rather be hit in the arm by a 30mm round (taking your arm off), or hit by several dozen 9mm rounds.

The problem isn't the impact, its all the kinetic energy needs to go somewhere. Either into the Earth which vaporizes rock and spreads it around, or in the atmosphere that flash cooks the hemisphere

If I'm in a tank or aircraft then I'll much better off with the 9mm. A huge fireball the size of new york could take out the planet. Distributed irregularly across the planet, many of those pieces would land in uninhabited parts of earth. Many would also land on houses, etc, and could potentially still kill millions of people but that's not the same as causing a global winter.

Re:Effect of nukes on NEOs

[DamnOregonian]

What sort of nuclear engine are you envisioning that would match the thrust of bombs boiling off the asteroid's surface in a big plasma wave?

I'm pretty confident that absorbing half of the energy output of a significantly sized fusion explosive (say, dozens of megatons) is going to do a lot more for you than just the ablative propulsion effects of the vaporized surface.

You're still going to send a pressure wave through that rock that is going to be a very formidable force in comparison to the very weak gravity holding it together.
This obviously isn't too helpful for a world-ending impactor (hundreds of miles+), but I'm guessing highly dangerous ones of that size and smaller could be reduced to buck shot.

One NASA-funded plan involved hitting it with an impactor first and then having the nuclear explosive follow it in. Even more energy absorption, and even more fertile ground for a very serious pressure wave.

The 5MT device detonated 1.8km deep on Amchitka lifted the ground at the surface by 20 feet. Imagine what that'd be like without 9.8m/s^2 of force pulling it back together, and without the weight of nearly 2km of rock to fight the expansion.

Re:Effect of nukes on NEOs

[DamnOregonian]

No, because those millions of small pieces release the same amount of energy into the Earth system, just now into the atmosphere now rather than the planet surface

You start with an incontrovertible claim,

Rather than ejecting material, earthquakes, tsunamis, you flash fry the hemisphere

And you use it to justify pure poppycock?
The atmosphere is big. The earth- it's also really goddamn big. The energy required to raise a hemisphere's atmospheric temperature enough to "fry" us is so goddamn big that there's no point in worrying about it. If something the size of Texas is about to hit us, we're just fucked.

The beast that (I guess contentiously, now?) knocked out the dinosaurs, spread across an entire hemisphere would yield about 193MW/m^2, to dissipate through a 100km column, giving us... 1.9kW/m^3 of dissipation, assuming impossibly worst case scenario (instantaneous thermal conversion across entire air volume)... which is quite survivable.

Realistically, the dissipation will be far better distributed over time and area (a lot of impactors will take long paths through the atmosphere, being not direct hits, better improving their dissipation at high altitudes)

It's not a... "good" thing, for sure... But it's not the total annihilation of a hemisphere.

Re:Effect of nukes on NEOs

[ShanghaiBill]

This obviously isn't too helpful for a world-ending impactor (hundreds of miles+)

Anything that size is already known. It is unlikely that any NEO bigger than a few km, or about 10 billion tonnes, is still undetected. For a NEO that size, a 10MT warhead (about the size of a minivan) could blow it to smithereens.

NASA is currently working on detecting NEOs between 140m and 1000m.

Re:Effect of nukes on NEOs

[Anonymous Coward]

We aren't talking about blowing up a truck on the highway, it's more like throwing firecrackers at a truck on the highway.
We are talking about object that would cause a significant amount of damage to Earth. A nuke would have to be equally powerful to blow it up.
Up to this date no nuke has been manufactured that would threaten life on Earth if detonated.
Any NEO that could be realistically blown up by a nuke is so small that it might be preferable to just evacuate the area and let it hit Earth anyway.

Re:Effect of nukes on NEOs

[Anonymous Coward]

Many more pieces, with a lot more surface area to:

1) burn up with.
2) decelerate with.

That's worse. With one big impactor, much of the energy gets dumped in the lower crust, or radiated back into space from the centre of the big, glowing crater. With lots of little impactors, all of the energy gets released in the filmy little soil-and-air layer where we live.

Furthermore, peak overpressure from a blast falls as 1/r^3. (1/r^2 from the usual energy-per-area, plus another 1/r as the blast smears out in time.) So, for the same total yield, you get more area covered with a given peak overpressure if you split the yield up into lots of individual blasts rather than one big one. This is the same reason ICBMs are armed with a bunch of small nuclear bombs (MIRVs) rather than one big one.

Re:Effect of nukes on NEOs

[Anonymous Coward]

While on a practical sense you may be right, the idea that they'll have the same velocity is completely false.

No, it's close enough to being correct. Orbital velocities are of order 10+ km/s. A nuclear bomb has enough energy to give a decent-sized asteroid a velocity of a few m/s. So the original velocity will be changed by <<1%.

That is sufficient, however, if you use the nuclear bomb to give the asteroid a little nudge sideways, by a few m/s, a year or so before it impacts. That's enough to make it miss the Earth. The GP was pointing out that this is the correct solution, rather than ham-handedly blowing the asteroid up (and being hit by the debris, which may be worse than the original asteroid).

Re:Effect of nukes on NEOs

[rseuhs]

In fact nukes could be used to send huge amounts of material into space (see project Orion) which could be neccessary to stop an asteroid, even if the actual method of using it is a gravity-tractor, mirror or something else.

Re:Effect of nukes on NEOs

[Stuarticus]

Nah, steer it into the moon, free fireworks!

Re:Effect of nukes on NEOs

[Anonymous Coward]

The odds of such an object (large enough to see from far far away, and headed right dead center for Earth) showing up in the next 250 or so years that we could conceivably still be bickering about nuclear weapons is amazingly small. Like smaller than the odds of a hooker showing up in the next 30 minutes to give you a free blowjob. Come back in 30 minutes if this didn't happen. OK great you're back. The kinds of objects they are proposing to disrupt are small, hard to see until they are almost here, capable of causing moderate damage (think: the first part of Armageddon, not the rest of it) and well worth shattering into 10,000 smaller pieces that will mostly burn up or cause inconsequential damage.

Re:Effect of nukes on NEOs

[tnk1]

If we managed to get it down to pieces below a certain size, yes, but we're unlikely to atomize something over a certain size. We avoid a huge single or clustered impact, but you will be left with multiple megaton-yield impacts in the wider area of effect. And that's effectively the equivalent of a nuclear war of some scale, the intensity of the bombardment obviously related to how much material there was to hit the planet.

Re:Effect of nukes on NEOs

[kellymcdonald78]

Lets take a 1km object, assuming a standard density carbon chondrite meteorite, it weighs in at 1.6E13 kg. Assuming we manage to blow it up into 20m chunks (about the same as the Chelyabinsk meteor). That's just shy of 2 million separate pieces, each dumping about 500kt of energy into the atmosphere or or about 3.5E15J of energy. This is enough to raise 5 billion cubic meters of air by a 1000C, or enough to lite the continental US on fire. This is just based on the pure conversion of energy released into heating of air. No radiative thermal effects have been taken into account. Note this for a smaller object. Chixulub was 10 times bigger

Re:Effect of nukes on NEOs

[kellymcdonald78]

It's not just the energy of things landing on your head. All that energy still goes somewhere, it doesn't just magically dissipate just because you've blown it into little pieces. Sure you don't get one big crater that puts enough dust into the atmosphere to cause global winter. You lite the hemisphere on fire which generates enough soot to cause a global winter. Note the fireball for Chixulub was in the hundreds of kms in diameter

Re:Effect of nukes on NEOs

[Maury Markowitz]

> I'm pretty confident that absorbing half of the energy output of a significantly sized fusion explosive

How do you propose to do that?

In space, the primary effect of the bomb over any sort of range, like a kilometer, is x-rays. These rapidly heat nearby objects and cause shock waves. The energy transfer is not particularly efficient.

They work great against RV's because the shock wave can cause the heat shield to detach from the underlying aerostructure. Against something like an asteroid I suspect it would damp out rather rapidly.

So that leaves offgassing from the outermost layer of the asteroid. That might be what, 0.1% efficient?

Take a liquid sodium reactor, connect it to an electrical heater that scoops up and melts the asteroid material. Allow that to radiatively cool (and even regenerate the heat) and then fire that out of a mass driver. The total delta-v-per-pound-of-fissile is going to be at least one order of magnitude better.

Re:Effect of nukes on NEOs

[kellymcdonald78]

Can you show your math? I just did the same with a 1km impactor blown into 2million chunks (one thousandth the mass chixulub), resulting in enough energy to light the continental US on fire. Chuxulb weighing in at 1E15 kg (low estimate), smashed into 20m pieces (the same as Chelyabinsk) would result in 1E8 pieces (Chelyabinsk weighing in at 10000 tonnes) , each dumping 500kt of energy into the atmosphere, or 2.09E23J. That's enough to raise the temperature of the ENTIRE atmosphere of the planet by 40 degrees (2.09E23J / 1005 specific heat of air / 5E18kg mass of atmosphere)

Re:Effect of nukes on NEOs

[Anonymous Coward]

Actually we are monitoring near-earth objects and would know that one is coming way in advance. The easiest way to avoid a collision by a larger object that would not just burn up in the atmosphere is to send a space probe to intercept attach to it and just adjust its orbit a little bit, so it misses.

Using nukes to blow up incoming asteroid is a silly idea that only works in Hollywood movies.

Re:Effect of nukes on NEOs

[Anonymous Coward]

There is no way to predict how big the pieces will get and they will still hit Earth. This is definitely high-risk, low gain proposition.
On other hand you can use orbital mechanics in your favor and just boost the rock so instead of lithobreaking the object does gravity assist. Voila.

Re: Effect of nukes on NEOs

[Anonymous Coward]

I highly doubt that the specific impulse/delta v of a nuclear explosion would be enough to change the orbit of a giant rock in any meaningful way. Also there is zero predictability of how the rock will breakup, if it is actually done it would be purely from political pressure to be seen as "doing something".

Re: Effect of nukes on NEOs

[KGIII]

Thank you. I watch too many documentaries. Those who would use a nuke for this are not going to blow the object up - they are going to blow up near it so that they change the orbit. At least that is how I understand it.

Re:Effect of nukes on NEOs

[Anonymous Coward]

Bomb set distance away from NEO; is a little nudge.

Re:Effect of nukes on NEOs

[tsotha]

Thing is... we already have lots of nukes, so we don't have to build them to stop NEOs. We just have to put existing warheads on more powerful boosters. That's why he's asking if we should "retain" nukes, because his assumption is arms control will eventually eliminate them. Too me it seems like a moot point, since I doubt we'll ever get rid of nuclear weapons for a whole host of practical reasons.

Re:Effect of nukes on NEOs

[tsotha]

No way. The danger someone could seize space based nukes and actually employ them is so close to zero it's academic.

How are you going to use them?

[pj2541]

And what delivery mechanism do you propose we have ready for those devices? Its not like we have superorbital spacecraft just lying around.

Re:How are you going to use them?

[SensitiveMale]

Why the two top secret X-71 space shuttles, Freedom and Independence of course.

Re:How are you going to use them?

[AK Marc]

The most sense is to build a nuclear launch facility on the dark side of the moon, with rockets that are designed to be accurate in space, but unable to target the Earth, so there's no chance for it to be used against us. Though, not sure if that's possible. You want them in a stable orbit (the moon is moving away, not closer) and you want them as far out of the gravity well as possible. Aside from a firing station in a lagrange point, which is less stable than the moon, the moon seems the most logical place for anti NEO nukes.

Re:How are you going to use them?

[TWX]

If one puts nuclear devices into orbit, I expect that would would place solid-fuel rockets into orbit attached to the nukes. So long as they're not segmented with O-rings like the ones on the Space Shuttle they can probably remain up there service-free for decades and still function as intended.

Re:How are you going to use them?

[CrimsonAvenger]

The most sense is to build a nuclear launch facility on the dark side of the moon, with rockets that are designed to be accurate in space, but unable to target the Earth,

I'm interested in the notion of a rocket on the moon that can reach a NEO but NOT the Earth.

Alas, ain't going to happen. If a rocket can do lunar escape speed, it can hit the Earth. And lunar escape speed is pretty much mandatory for hitting an NEO (unless the NEO passes within about one lunar diameter of the moon)....

Re:How are you going to use them?

[rubycodez]

Of course the earth can be targeted from dark side of moon, and vice versa.

Re:How are you going to use them?

[Anonymous Coward]

The most sense is to build a nuclear launch facility on the far side of the moon...

FTFY. Don't make the pink floyd mistake...

However, it will be very difficult to monitor and trigger such an installation from earth seeing that we don't have a good satellite constellation coverage around the moon. Although perhaps there can be a compromise to take advantage of libration...

-slew

Re:How are you going to use them?

[Anonymous Coward]

If one puts nuclear devices into orbit, I expect that would would place solid-fuel rockets into orbit attached to the nukes. So long as they're not segmented with O-rings like the ones on the Space Shuttle they can probably remain up there service-free for decades and still function as intended.

Sadly solid rocket fuel does not have an indefinite shelf life (years, not decades). The consequence of this in the western united states is that there are many communities that have massive groundwater pollution from Ammonium perchlorate refueling operations.

-slew

Re:How are you going to use them?

[AK Marc]

So your answer is the typical "If I can't think of a solution in 10 seconds, that's proof it's impossible" Slashdot answer.

I can think of multiple ways to solve the answer. But now, it'll be a personal issue where you'll assert I'm wrong, rather than thinking about the issue, so there's no point to try to describe how to "solve" the issue.

Re:How are you going to use them?

[AK Marc]

I'm interested in the notion of a rocket on the moon that can reach a NEO but NOT the Earth.

Yet, you assume it impossible and don't try to solve the problem.

Alas, ain't going to happen. If a rocket can do lunar escape speed, it can hit the Earth.

You are assuming "rocket", when I put no such constraint on the "launch facility". Your failure was one of imagination. A facility on the dark side with a railgun launch and insufficient fuel to turn to hit Earth, but enough to steer to hit a NEO would meet the requirements.

It always amazes me the people on slashdot who think that if they can't solve something in 10 seconds, it's impossible.

Note, I never said "practical", and I'd assume that a complete physical compromise of the base would allow the new owners to reduce the launch speed to a sub-escape velocity such that the launch will result in a Earth or Moon impact, and the steering would be used to pick the location on Earth hit. But that level of compromise would be quite substantial, unless there are multiple bases on the moon, which is a different design constraint. And the level of sophistication to launch an moon invasion of a guarded facility would be enough to just make a railgun on the near side and launch rocks at the earth to a similar result, so there'd be no reason for anyone to consider a physical penetration of the facility to be a consideration. When someone is close to the ability on the moon, they could build nukes on the Earth, or you just launch all the nukes into the sun.

Re:How are you going to use them?

[AK Marc]

No, the "dark" side of the moon is the name for the "far" side of the moon. It doesn't imply it's "dark" as in shadow from the sun, but dark as in we can't see it. It was named before people understood it, so yes, it was named poorly, but that's how it's named.

However, it will be very difficult to monitor and trigger such an installation from earth seeing that we don't have a good satellite constellation coverage around the moon.

If we were wanting to build a station, we'd launch a satellite into L4/L5. Or a long ring around the moon. Have you seen the proposal to ring the moon in solar panels? Make that ring, and have the launch station powered and communicated with through the ring around the moon.

Re:How are you going to use them?

[Sardaukar86]

FTFY. Don't make the pink floyd mistake...

Maybe you weren't listening hard enough:

"There is no dark side of the moon, really. Matter of fact it's all dark."

Re:How are you going to use them?

[Anonymous Coward]

We have standardised upper stages to take satellites up to geostationary orbit. That actually takes more delta-v than putting them into an Earth escape trajectory. We can make a nuclear bomb lighter than a communications satellite, which expands the range further.

So, I guess we probably do have superorbital-capable spacecraft just lying around (or coming off a production line, anyway). What we don't have, though, is a standardised communications system for spacecraft in deep space (i.e. outside the Earth's orbit).

Re:How are you going to use them?

[slew]

FTFY. Don't make the pink floyd mistake...

Maybe you weren't listening hard enough:

"There is no dark side of the moon, really. Matter of fact it's all dark."

AFAIK, that comes from a set of interviews recorded by Roger Waters to create background voice ambiance for the album (and was enshrined in the final mastering) was actually made by Jerry Driscoll.

The full quote was apparently, "There is no dark side in the moon, really. Matter of fact, it's all dark. The only thing that makes it look light is the sun." I'm guessing Jerry made that statement to illustrate the mistake that Pink Floyd made, but I could be wrong...

Re:How are you going to use them?

[slew]

Oh yeah and sadly I *did* listen to it quite a bit. When the Darkside of the moon album dropped from Billboard's list of top albums back in 1988, the person in the dorm room next to me played a 24 hour/day, 7 day/week vigil on his stereo system until the housing department finally had him shut it down for keeping people up at night (esp time and money)...

Although I still have the album myself, I haven't listened to it since '88 because of this incident (and I freely admit to destroying several cassette tapes of Darkside during that 7 day/week vigil/torture)...

Re:How are you going to use them?

[Sardaukar86]

Sounds like a great way to ensure you never want to listen to the album again! :)

You are clearly an enlightened chap, it's always interesting to read a little history. If you enjoyed Jerry's interview, look for the full interview with the doorman, Roger the Hat. As you're no doubt aware, he contributed the "Short, sharp shock, dig it?" amongst other gems like the nutty laughter in Brain Damage.

Re:How are you going to use them?

[Sardaukar86]

Crap, I just realised I conflated Roger the Hat with Jerry Driscoll; Roger was a *roadie*, Jerry was the doorman, apologies.

Re:How are you going to use them?

[david_thornley]

If it's got the ability to hit lunar escape velocity, and has any ability to aim, it can hit Earth. If it isn't aimable, it's not going to be in the exact right orientation. If it can't reach lunar escape velocity, it's limited to hitting things close to the Moon. Not only is there no guarantee the NEO will be considerate enough to do a close pass on the Moon while incoming, but nudging something big roughly around Lunar orbit is going to do absolutely no good, since it needs to be nudge when there are weeks, at least, before the impact.

It's not that I'm assuming anything is impossible, it's that you're putting incompatible constraints on the problem. If it can be used effectively against a NEO, it can hit Earth.

Re:How are you going to use them?

[AK Marc]

If it's got the ability to hit lunar escape velocity, and has any ability to aim, it can hit Earth. If it isn't aimable, it's not going to be in the exact right orientation.

Something with a high launch velocity and weaker maneuvering thrusters wouldn't be able to hit the Earth, but could hit any other object in the Solar System. Like the "aimable bullets" people are coming out with will let you hit something that's in your field of fire, but not outside it. It would be impossible to hit yourself with one. So use something similar fired from the moon (pointed away from the Earth).

Though yes, you should be able to hit the Earth firing around the Sun or other gravity well as a slingshot. But the idea is to make it impossible for a direct, well aimed shot at the Earth from the moon.

Re:How are you going to use them?

[tsotha]

Duhh! Space Nazis do it all the time.

Re:How are you going to use them?

[david_thornley]

We're trying to explode the nuke a precise distance away from the NEO over a precise point. If we can do that for a target 10km across, we can almost certainly hit Los Angeles. So, although you could theoretically set the thing up to fire greater than Earth's escape velocity, and use some sort of unobtainium lock to prevent it from firing more slowly, the ability to hit anything in the near solar system precisely includes the ability to hit a large Earth city.

Re:How are you going to use them?

[AK Marc]

and use some sort of unobtainium lock to prevent it from firing more slowly

Yes, like a railgun launch, or solid rocket stage, both theoretical and without any precedent.

what the fuck.

[rogoshen1]

"keeping 10 or 20 nuclear devices available might be a good idea..."
"insignificant compared to the thousands now held in military arsenals."

Okay, so a solved problem? Got it.

Re:what the fuck.

[Calydor]

How did that movie quote go?

I don't fear the man who has a thousand nukes. I fear the man who only has one.

Something like that, anyway.

Re:what the fuck.

[Anonymous Coward]

It's worse than that. The proposition implies that some agency like NASA ought to make, or acquire, the nukes. Why would we do that? Why would they do that?

NASA isn't set up to keep safe custody of nuclear wea-, er, NEO diverting tools. The military has that infrastructure. So we divert nukes to a civilian agency who doesn't have the people or procedures required to keep them safely. Just so that we can say "this box of nukes is for use on NEOs only"?

We might need to set up a mutual assistance agreement between the military and the civilian space agencies. That would be a good idea. It's a bad idea to give nukes to the space agencies, "just in case we need them for that purpose." And unless I miss my guess, the civilian space agencies won't want the responsibility to maintain the nukes anyway.

Huh

[Anonymous Coward]

i thought nukes were useless for this purpose

Re:Huh

[Anonymous Coward]

They are pretty much useless. Nukes would be only useful in the case of an NEO that just happened to 1)be detected in plenty of time, 2)be traveling at a very slow velocity, 3) be of a relatively small mass.

Re:Huh

[blue9steel]

ICBM are useless for this purpose as they don't have the range and power to get the explosive into the proper position for a deflection shot. Developing a useful launcher and associated hardware/software is well within our capabilities if we decided it was important.

Delivery system?

[Anonymous Coward]

Is there some delivery system that is planned to be kept on hand as well, or is this just so we can form a suicide pack and blow ourselves up before a hypothetical event?

you don't see the one that hits you

[ihtoit]

in fact, we didn't see ANY of the more recent impacts coming until the dust had settled. So what fucking use is a nuke again?

Re:you don't see the one that hits you

[Anonymous Coward]

The ones we can see coming are the ones that will destroy civilization; the small ones aren't a big deal.

Re:you don't see the one that hits you

[TWX]

The recent impacts also weren't large enough to cause more than regional damage. Didn't even reach regional surface devastation like Tunguska or regional geologic devastation like Barringer Crater.

I'm assuming that we'll never be able to reliably detect impactors as small as Tunguska, but we might be able to detect Barringer-sized objects if we make an effort to look for them.

I dunno....

[Anonymous Coward]

Should cultures of a deadly virus that was long ago eradicated be kept on hand, just in case a bit slipped through the cracks somewhere that could lead to a new epidemic?

Answer that, and you have the framework needed for an answer.

Or

[Anonymous Coward]

We could just keep the thousands we have, because that's what were going to do. I very much doubt we're giving them up any time soon.

Big Question:

[Anonymous Coward]

Who would have physical possession of said nuclear 'devices', and who would have the authority to use them?

Re:Big Question:

[rubycodez]

as always
1. armed forces of nuclear states
2. politicians

Don't worry, Israel has extras.

[Anonymous Coward]

Ask them.

Yeah well

[Anonymous Coward]

I'd still keep a couple around for the Russians anyway.

Too late, too little

[sverdlichenko]

How could 10 or 20 nuclear devices help against any significant near earth object?

Re:Too late, too little

[Sowelu]

Give it a tiny nudge when it's far away. Seems like you'd want very different kinds of missiles to do that though, designed to fine tune their course in space instead of air.

Re:Too late, too little

[sverdlichenko]

Look at the Orion project, they intended to use this bombs in thousands. With much weaker payload, but the mass of the ship is a few orders of magnitude less too. I seriously doubt 20 nukes would be enough for any really dangerous thing at the range we can be sure if it would hit the Earth or not.

Re:Too late, too little

[david_thornley]

We're very good at detecting and locating large objects in space, and getting better. If we don't have the necessary accuracy now, we'll develop it soon.

Re:Too late, too little

[tsotha]

It's not uncommon to detect near-misses an orbit or two before they get close. For something like that a single nuke would be just fine, since a tiny perturbation would make it miss by a lot.

Re:Too late, too little

[sverdlichenko]

It's all about precision. Knowing something will come near Earth, say inside Moon's orbit, and knowing something will hit Earth are two very different knowledge. Would be very disappointing to get a nuke to the object only to change near miss to direct hit.

No.

[dskoll]

A nuke is unlikely to have much effect on anything big, other than to break off additional chunks that are harder to stop and track.

Re:No.

[Anonymous Coward]

That in and of itself is probably a deflection method, not a preferable one but an option. Drill a few hundred feet into one side of a NEO, put a nuke down the hole and detonate it. The resulting thrust from ejecting large chunks of rock out one side of an asteroid would most definitely impart some serious delta V. Sure the planet may get hit by the ejected chunks but it may at least drop it from a Extinction Level Event to a terrible catastrophe.

Energy

[fkodama]

Guess it should be kept to generate energy in a future where this kind of tech could be controled, the danger is that if society can't be controled does such devices with control could possibly be controled? U.S. citizens think in peace by now and if in 1k years that tech still has no control, where the bombs will fall? devices are pratically imortal compared to a social setup.

Nuclear Interception of NEO's

[Anonymous Coward]

This is a silly idea. Not only would the interception have to be done using a space launch (something I'm sure we have the capabilities to do NOW, even if certain countries deny having nuclear capabilities in space) but we have a pretty GOOD idea that the effect would be marginal at best.

A better solution would be to detect the NEO well before it hits, intercept it, and drag it to a better orbit (either solar system escape, or better, an intercept orbit with the sun) using either gravity or an ion engine over a sufficient length of time.

Thinking you can blow up a NEO using nukes is just a BAD idea.

Re:Nuclear Interception of NEO's

[Anonymous Coward]

The best idea is to send a rag tag bunch of oil rig guys with just a montage of space training to land on an asteroid in an untested spacecraft, no doubt having to leave one of their own behind to manually detonate the nuke in a teary-eyed finale sequence that results in saving all of mankind so that we can go on killing each other and violating the environment and occasionally having sex outside our species.

Shitty risk analysis

[bluefoxlucid]

"The risk posed by NEOs is not zero, but it is small relative to the risk posed by nuclear weapons." Even so, Baum writes, since the consequences of an NEO hitting the earth would be catastrophic

Wrong. The risk posed by NEOs is small in probability and extremely high in magnitude; the risk posed by nuclear weapons is larger in probability and smaller in magnitude. Space rock impacts cause mass extinctions; nuclear weapons detonations cause international incidents and poorly-defined human responses.

We have a fantasy that one nation launching a nuke will result in all nations nuking each other until the earth is a ball of slag; a more rational mind recognizes MAD as suggesting one nation launching a nuke will result in all nations reducing that nation to a ginormous glass parking lot. In reality, we haven't seen that situation, and our assessment of human psychology suggests it's more likely that a single strike (rather than constant, ongoing bombing) would result in shock, hesitation, and a lot of talking; ongoing nuclear bombing of a single nation would probably result in all other nations shaking like water-laden chihuahuas while trying to talk down the offenders (see Germany. Twice. With all of Europe wetting itself both times).

Nuclear war has a low but significant probability, itself spanning a wide berth of probable outcomes with impacts ranging from nothing notable to devastation. The human race would survive even in the worst projections, just bombed back into the stone age. NEO impacts have an insignificant but real probability, when limiting our view to those objects which would destroy the earth. Limiting nukes to "slag the human race back into the stone age" produces a similarly insignificant but real probability, more attainable by joint intent of all world leaders but hardly more likely; expanding NEO impacts to "a range of possible outcomes from smashing buildings to vaporizing all life off the planet" and scaling each magnitude of impact against the various magnitudes of impact of nuclear war immediately demonstrates that we take meteor impacts pretty frequently, most hitting uninhabited areas or blowing up in the sky with no damage, so nuclear war seems vaguely more likely in all scenarios.

The absolute outcome of a planet-killer tells you it's easier to hide from nuclear war. A few nukes are an acceptable trade-off, since disarmament is impossible and creates its own risks (i.e. secret nuclear stockpiles--if you really disarm, how do you know the other guy isn't lying, and ready to nuke you when it's clear you really have no nukes?)

Re:Shitty risk analysis

[phantomfive]

see Germany. Twice. With all of Europe wetting itself both times

I see you're talking about Hitler......what is the second time?

Re:Shitty risk analysis

[Anonymous Coward]

MechaHitler!

Re:Shitty risk analysis

[Anonymous Coward]

WW1

Re:Shitty risk analysis

[bluefoxlucid]

In both World Wars, the Europeans resisted entering a war on the hope that Germany would subjugate a few neighboring countries and then settle down. This is why Mao killed 170 million Chinese and nobody cares--he was taking over China--but Hitler killed 8 million Jews and everyone cries genocide--he was marching across Europe trying to take away the power of powerful people, so they made him a vicious demon in history. They hardly mention the repeated chastising of Germany, telling them they've gone far enough and should now cease expanding, rather than forcing them back into the German state and returning conquered Poland and Austria to their rightful peoples; nobody wants to admit we'd all have been just fine with Hitler microwaving all the Jews and Gypsies, so long as he kept to borders well outside our comfort zones.

Re:Shitty risk analysis

[Anonymous Coward]

see Germany. Twice. With all of Europe wetting itself both times

I see you're talking about Hitler......what is the second time?

Obama.

Re:Shitty risk analysis

[phantomfive]

WW1 was more a lesson in "balance of powers" than of anything else. Each side was maneuvering to get more and more power. Each side went zealously into the war.

Sober minds realized that war would be bad, but generally the populace sang dulce et decorum est pro patria mori.

Re:Shitty risk analysis

[Anonymous Coward]

In both World Wars, the Europeans resisted entering a war on the hope that Germany would subjugate a few neighboring countries and then settle down. This is why Mao killed 170 million Chinese and nobody cares--he was taking over China--but Hitler killed 8 million Jews and everyone cries genocide--he was marching across Europe trying to take away the power of powerful people, so they made him a vicious demon in history.

Because killing 8 million Jews wasn't enough to make a vicious demon?

Re:Shitty risk analysis

[Anonymous Coward]

I'm willing to bet both you guys are the ones that get stuck generating "root cause analysis" far, far away from the nearest hedgerow.
Or you could be a post Schwarzkopf general. I'm not saying that to knock you, I'm just letting you know that based on the "those that fail to learn from history" adage, WWIII is in your future.

Re:Shitty risk analysis

[phantomfive]

Hedgerows were more of a WW2 thing, mate.

Re:Shitty risk analysis

[david_thornley]

Another issue was that there were two sides. The balance of power in Europe had required somewhat fluid alliances. That they proved more fluid in practice (Italy was allied with Germany and Austria-Hungary but wound up on the Allied side) had no influence on starting the war.

Re:Shitty risk analysis

[phantomfive]

That they proved more fluid in practice had no influence on starting the war.

I'm not sure what you're saying here

Re:Shitty risk analysis

[david_thornley]

Italy was allied to Germany and Austria-Hungary, and all the decisions leading up to starting the war had to take that into account. Once the war was started, Italy stayed neutral for a time and then joined the Allies. The Central Powers alliance was more fluid than anticipated, but since this wasn't apparent until after the start of the war, it didn't affect the war starting.

don't need a nuke, just Newtons Law

[k6mfw]

David Morrison of SETI has said only need to nudge it by impacting it with a spacecraft, that will change it's trajectory [of course need to do it way ahead before impact, and careful calculations]. Other than that, sounds like excuse to keep some A or H bombs lying around. And of course using them on a NEO is very dramatic, add Bruce Willis and you have a classic (there was another asteroid movie that came out same time, it has been forgotten). Plus ever since the movie "Marooned," a common movie plot of problem solved are secret USAF spaceships (as illustrated by SensitiveMale).

Re:don't need a nuke, just Newtons Law

[Anonymous Coward]

close, but not quite.

You don't change the trajectory by impacting it with a spacecraft (At least in the classic sense ), you change it by changing its angular momentum thereby changing it's orbit.

I expect that's what he meant, but most people don't get the difference.

Re:don't need a nuke, just Newtons Law

[bobstreo]

I think robot controlled solar sails would even work to adjust trajectories, given sufficient time and warning.

Nukes? If there is a suddenly detected chunk of rock/ice/metallic whatever that big, that close, probably wouldn't help
much.

I prefer nudging even with nukes, not trying to blow up the object.

Re:don't need a nuke, just Newtons Law

[DroolTwist]

(there was another asteroid movie that came out same time, it has been forgotten)

Are you talking about the movie Deep Impact?

deck chairs on the Titanic

[Pseudonymous Powers]

The article linked in the summary talks about international negotiations to decide to use the nukes. If it's a clear existential threat that we can see coming from far enough away to achieve that kind of international consensus, I think the relative expenditure of time and will that it would take to build a few nukes would be negligible. And as others have noted, the real limiting factor will more likely be that we don't have any delivery mechanism in place to get the nukes to the asteroid, and that's not something you can bang together in a weekend. As a rough approximation, compare the Manhattan Project to the Apollo Program.

Put large ships in orbit for NEO issues

[Anonymous Coward]

We just need to be willing to put 2-3 of these in orbit.

https://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29

If designed correctly they are big enough to push NEO's, and also solve the trip to mars problem.

Irrelevant

[sycodon]

We have no delivery system, no fire control system, probably no software to guide it to the object, no information on a nuke's impact on the object, etc.

It's like trying to decide if you should keep that 105 howitzer shell around when you have no gun, no one trained to use it, and no way to target anything with it.

Re:Irrelevant

[NEDHead]

We have no delivery system, no fire control system, probably no software to guide it to the object, no information on a nuke's impact on the object, etc.

Speak for yourself

Re:Irrelevant

[aaron4801]

But we DO have Bruce Willis and Ben Affleck.

Re:Irrelevant

[TWX]

Just about all of the pre-Apollo American launches of humans into space was done with ICBM rockets. Lots and lots of satellites were also launched with ex-ICBM Titans/Titan IIs, and Atlas rockets through the eighties were based on the ICBM version of the Atlas.

Admittedly, these rockets were meant for orbital insertion or suborbital spaceflight, but that they have been adapted for nonhostile or less-hostile space applications implies that it would be possible to continue to do that, and that there is software/firecontrol that could be modified to do the job.

Re: Irrelevant

[ArmoredDragon]

Ben Affleck will be too busy getting taco flavored kisses.

Re:Irrelevant

[Type44Q]

I suppose if they were given enough velocity... but it'd have to be a lot.

Re:Irrelevant

[khallow]

Nuclear weapons tend to be more forgiving of the delivery system than a howitzer shell. And we do have the rocketry thing working pretty well. I think delivery system, fire control, software, etc will just not be that hard.

And one can always blow up a few asteroids to see if nukes work.

Re:Irrelevant

[Anonymous Coward]

Actually we (the US) have a build spec for the very long standing Centaur space vehicle to accomplish this. The Russians likewise could potentially use their Fregat. However to my knowledge we do not have any vehicles just waiting around for use, and it would take a month or so to build them or divert the lines, and then get the launch vehicles ready. Although supposedly the USAF has some old freefall nuke weapons actually already tasked for this!

Re:Irrelevant

[strikethree]

We have no delivery system, no fire control system, probably no software to guide it to the object, no information on a nuke's impact on the object, etc.

Eh? We have the technology to fire a missile from a ship floating in the ocean and hit a relatively small satellite orbiting the planet. I do not think it would be THAT much different to fire a missile from land to somewhere just past orbit and hit a relatively large object.

Are they the exact same problem with the exact same missiles, targets, and locations? No. Regardless, the problem of sending stuff accurately past planetary orbit is a solved one. The only question is how quickly can they do it within the new set of requirements.

It's like trying to decide if you should keep that 105 howitzer shell around when you have no gun, no one trained to use it, and no way to target anything with it.

It is not like that at all.

We don't have a launch system

[tekrat]

We have nothing that will take a nuke far out enough to use it against a NEO. I am assuming that this is one of those scenarios where we discover the object too late to do anything but attempt blowing it up. Therefore it's what, between the earth and the moon?

All our launch systems are LEO, and then use gravity assist slingshots to get themselves into the outer solar system. We have NOTHING that can go directly to the target. Therefore we are essentially screwed, because by the time we got the nuke to the target (read as days of orbits), it's already 15 minutes away from impact, in which case, the nuke isn't going to do much except shut down the electrical grid from the EMP, before we are wiped out.

Radioactive Fallout

[Roger W Moore]

You forgot:

3) Scatter radioactive fallout with

Still cancer takes longer to kill you that a massive asteroid impact followed by a decade of winter so I suppose it's a win?

Re:Radioactive Fallout

[g0tai]

Heh, that's actually a good one that I had completely missed! I haven't a clue about how much fallout there would be, or if it was spread over a wide enough area (hopefully due to pieces burning up) if the residual would be enough to worry about!

Re:Radioactive Fallout

[Anonymous Coward]

That's a long, long way from being a significant concern. We're talking about the fallout from one nuclear bomb, compared to the hundreds that have already been tested here on Earth - and those hundreds of bombs have added something like 0.1% to the natural background radioactivity. You may as well worry about lung cancer from the exhaust of the rocket that launches the bomb, or global warming from sunlight reflected from the bomb's casing.

Re:Radioactive Fallout

[Roger W Moore]

It depends on how spread out the fallout is. Spread over a hemisphere it is not a problem but if small meteorite fragments streak over a city leaving a contrail of highly radioactive fallout it may be a big problem for certain locations even if nothing significant makes it to the ground. It is also worth pointing out that the size of a nuclear device capable of shattering an asteroid worth worrying about will be extremely large and multiple such devices might be required.

Small reactors and ion thrusters

[presidenteloco]

I think you want to land nuclear reactors with ion thusters on the surface of the NEO, a long time back from possible impact.
Ideally with some technology that can convert material on the object to the right kind of ionized gas.

Energy = mv^2 /2 so you accelerate the ions in a beam at extremely high velocity, electrically.

You need a control system to only send out the ion beam each time a tumbling object is facing the correct way.

You run the ion thrusters for months or years, and hope for the best.

Nuke

[BeemanIT]

The question I have is; will a Nuke work in space? We have atmosphere and a reaction which takes place here on earth but I'm curious as to how it will be possible to nuke something in a vacuum of space.

Re:Nuke

[presidenteloco]

Let me see, will a hydrogen fusion reaction work in space?

If I could only get the Sunlight out of my eyes, I could google that on my smartphone for you.

Re:Nuke

[Anonymous Coward]

I'm at a desk with no sun in my eyes, but didn't need google to tell me that nukes use fission not fusion....

Re:Nuke

[Anonymous Coward]

It's always good to ask questions about things you don't know about. Nuclear weapons do not require atmosphere to work, and will work just as well in space, except the shockwave would be greatly reduced. Reactions that burn (oxidize) materials require an atmosphere, or to have oxygen added from an external source. Nuclear explosions are not the result of burning materials. The explosives surrounding the fissionable material may require oxygen, but if so it would be provided in the bomb casing (not something I really want to go look up).

Re:Nuke

[presidenteloco]

thermonuclear warheads on ICBMs are hydrogen fusion bombs. I believe they are initially triggered with a smaller fission reaction.

Re:Nuke

[CrimsonAvenger]

I'm at a desk with no sun in my eyes, but didn't need google to tell me that nukes use fission not fusion....

Castle Bravo was in 1954. It wasn't the first fusion bomb (1952), nor was it the biggest (Tsar Bomba - 1961), but it exceeded expectations of blast (2-4 times expected) enough that it was the major source of radioactive fallout for the US till Tsar Bomba....

About the only people using fission bombs at this point are the North Koreans.

Re:Nuke

[BeemanIT]

Found the response to my question in this: http://www.scienceforums.net/t...

Re:Nuke

[david_thornley]

As I understand it, there's really nothing powerful enough to create a fusion explosion except fission bombs. Both of these work just fine in space. In fact, we've got a gravity-contained fusion reactor in space about 1 AU away.

Youll never get rid of them all

[Anonymous Coward]

Officially or unofficially, barring the complete collapse of society, as long as there is a humanity there will be nuclear weapons or worse. I don't care how many treaties, agreements, promises are made the major powers will always keep a few of them on hand for some reason or another. Suggesting that all of the nuclear powers are going to give up their nukes is like suggesting that all of the billionaires are going to give up most of their fortunes to the poor. So that makes the discussion kind of moot.

Re:Youll never get rid of them all

[Anonymous Coward]

Agreed.

Also, I'm not sure we should want to. The death toll due to wars has dropped by significantly since they were developed.

Solution in search of a problem

[damn_registrars]

This sounds like someone just trying to justify not getting rid of all of our nukes.

Re:Solution in search of a problem

[blue9steel]

Getting rid of all of our nukes would be about the dumbest thing imaginable. They're pretty much the only reason we didn't have WWIII and maybe WWIV.

Re:Solution in search of a problem

[damn_registrars]

Getting rid of all of our nukes would be about the dumbest thing imaginable. They're pretty much the only reason we didn't have WWIII and maybe WWIV.

Mutual Assured Destruction was just ... mad.

That said, what have our nukes done to prevent the war on terror? What have they done to prevent all the other wars we have fought in since WWII? You can make a (dubious) claim that the nukes on their own prevented other nations from attacking the US directly if you want, but conflict doesn't occur in vacuo on this planet. There are other factors that are arguably more critical to preventing war.

Re:Solution in search of a problem

[blue9steel]

Mutual Assured Destruction was just ... mad.

And very scary, but it did work.

That said, what have our nukes done to prevent the war on terror?

An anti-insurgency campaign in a couple of minor nations is not in the same weight class as a global conflict between 1st world powers. Allow me to demonstrate:

WWI Casualties: 17 Million
WWII Casualties: 60 Million
War on Terror Casualties: Debatable but likely less than 250k.

As you can see the other conflicts are roughly two orders of magnitude larger.

What have they done to prevent all the other wars we have fought in since WWII?

Congress hasn't declared war since 1941. If you want to count authorizations of military force then no, of course nukes haven't impacted that much since it's mostly the US taking on much smaller countries. (often with good reason, but we were hardly in danger of invasion)

You can make a (dubious) claim that the nukes on their own prevented other nations from attacking the US directly if you want, but conflict doesn't occur in vacuo on this planet.

I never claimed they prevent conflict, just major wars between nuclear armed states.

NO, NO, NO, NO, this is a BAD idea

[bobbied]

1. Nuclear devices are ineffective in space. This means you will have to use BIG ones, or you will have to use them early to nudge the object onto a different path. Bigger devices are harder to throw into space and detection and targeting of dangerous objects makes the problem all that harder.

2. Nuclear weapons in space is in itself insane and banned by multiple international agreements due to the danger they pose.

3. Nuclear material in orbit is dangerous because what goes up, must come down. We don't put nuclear power generators in space for a reason and putting a fission device in space would present the same kind of difficulty.

4. Nuclear devices are pretty fragile devices. Believe it or not, but there are issues with a high radiation environment for any kind of electronics and nuclear fuses are no exception. High explosives also are kind of fickle things, when you start talking about temperature changes between extremes commonly experienced in space. Nuclear devices make use of shaped charges and special detonation timing, all which can be very temperature sensitive.

5. Nuclear fission devices require regular maintenance - It's not much maintenance, but it's enough to be a problem if you have to go into orbit to service the thing that I'd suggest you not consider it.

6. An accidental malfunction would be a SERIOUS problem for the near by earth. If you accidentally triggered one of these things, say a radiation induced trigger, or cosmic ray induced malfunction, a lot of things could get broken on earth.

So for the above reasons, I say NO, this is NOT a good idea.

Re:NO, NO, NO, NO, this is a BAD idea

[Anonymous Coward]

Items 1 and 2 would be irrelevant in the face of the imminent end of humanity. Don't necessarily need big ones, more small ones could work just as well.

Items 4 and 5 are engineering problems. Difficult to be sure, but not insurmountable. Since nuclear weapons are currently designed to be mounted on intercontinental missiles I would think that there has already been much progress made here.

Items 3 and 6 imply not that we shouldn't put them in space, just that we shouldn't keep them near the Earth. Stick them on or in orbit around the Moon, or at L4/5.

Re:NO, NO, NO, NO, this is a BAD idea

[rubycodez]

Wow, you really spew a lot of things without knowledge of the subject:

1. Wrong, effective thrust producers in space when used as surface or subsurface boost.
2. nuclear weapons in space have already existed. insanity not a valid point to raise as the weapons themselves sufficient to destroy civilization many times over exist (though not enough to kill all humans, contrary to popular belief) and are under the control of POLITICIANS. Logic and sanity are left at the door.
3 nuclear weapons launched by rocket can withstand falling and impact into ground without detonation or material leak, already solved problem
4 - no, they are quite robust and many models designed to withstand thousands of g-force. bunker busting ones over 100,000 g's. Rad hardened electronics for space is a long solved problem.
5. - long solved problem, nuclear weapons have been stored in space in the past
#6 we face each and every day. Ground bursts of existing nuclear devices would be a huge problem.

Re:NO, NO, NO, NO, this is a BAD idea

[brambus]

1. Nuclear devices are ineffective in space.

Not the case. See Project Orion.

will have to use them early to nudge the object onto a different path

This would be the case for any asteroid defense and we're already capable of detecting and track most objects large enough to cause serious concern. With more investment, we'll only be getting better and be able to detect smaller and smaller objects.

banned by multiple international agreements

Banned due to potential for a space arms race over a potential war. Doesn't apply in case of joint global asteroid defense.

We don't put nuclear power generators in space for a reason

We can and regularly do send nuclear power generators into space, including fully-featured nuclear reactors. In related the news, we haven't all died yet.

4. Nuclear devices are pretty fragile devices & 5. Nuclear fission devices require regular maintenance

Just send many smaller ones. Even if some don't work, all you want to achieve is deflection. Pro tip: when not required, don't park the things in space. Keep them on the ground and launch them should the need arise. Any asteroid early-detection program gives notice years in advance (e.g. we learned about the close pass of 99942 Apophis a good 2 decades in advance).

6. An accidental malfunction would be a SERIOUS problem for the near by earth

Same problem applies for weapons stored on Earth. Fix is simple: keep the device disarmed and design in fail-safes. This has already been done. I 7 decades of nuclear weaponry, number of inadvertent nuclear detonations, even in case of accidental weapons drops: zero.

Re:NO, NO, NO, NO, this is a BAD idea

[bobbied]

Yes, we put nuclear powered spacecraft into space, I misspoke on that.. But what we DON'T do is put them in orbit. Nuclear powered craft are ONLY used for spacecraft which will be leaving earth orbit and not returning.

I'll try and explain why you don't want a nuclear device going off in space near the earth and rather have it in a bunker... First, you can physically render a nuclear device inert by removing parts of it. I believe they call it a "pill" and without it, it doesn't matter what you do to the device, it cannot become critical and cause a nuclear explosion. You store the "pill" separately from the device for a number of security reasons, and they don't come together until you want a device that can go critical when triggered.... Second, as odd as it may seem, having a device in a bunker is actually safer if it really did decide to go off on it's own. Being close to the ground, better yet UNDER ground helps to contain the blast and the adverse affects it creates. HEMP pulses are a serious problem as are X-Ray generation and a whole host of things which are bad from a nuclear device, but if the device is close to the ground, the area these things can affect is lower. So keep your nuclear devices UNDER ground, keep them disabled by storing that last bit of fissionable material in a totally different area...

Setting a device off in LEO is going to be a mess and it's going to affect a huge area.

Re:NO, NO, NO, NO, this is a BAD idea

[bobbied]

Wow, you really spew a lot of things without knowledge of the subject:

You too apparently..

1. For producing thrust impulses, any old explosion will do, but to actually impart enough energy there might be more effective ways than blowing something up next to it.... Hollywood movies aside..

2. Parking nuclear weapons in space is NOT accepted practice, slinging them on rockets and sending them though a ballistic arc to their targets is not the same thing as being in orbit. Sure, they can survive the rigors of being launched and doing a re-entry, but they are NOT built to stay in space very long. What's the average length of time from launch to target? 25 min? An hour?

3. Doing a ballistic trip and staying in orbit are two very different things. Case in point, Mercury missions verses Gemini missions from the 60's. With all due respect to John Glenn, It's a whole new level of complexity to be in orbit.

4. Sustaining G's is great, but that's not the problem in orbit or in space. The issues in space quickly become temperature management and power. Which is followed by navigation and fuel management once you start trying to stay in orbit. Being mechanically strong and able to handle high G-Loads is pointless. You just need to be strong enough to launch and handle the vibration of the assent phase, and after that? Nobody will care if you can do 2 G's or 2,000 G's.

5. I am not aware of any nuclear weapons being stored in space now or in the past. Any such storage would be in violation of standing international treaties, so if you have evidence of this I suggest you share it because we have a serious world wide problem if this is true. Plus, I would argue that ground storage of nuclear weapons would be MUCH safer, given that it's really easy to make them inert by physically removing some of the fissionable material. In fact, this is EXACTLY how they render nuclear weapons "safe", by removing what they call the "pill" from the device and storing them separately. So keep these babies on the ground where we have physical access and can keep them inert until needed.

6. Surface detonation of a nuclear device is FAR safer than one in LEO. The lower the altitude, the better... In fact underground would be good... The ground acts as a shield and although it would be a mess at ground zero, the blast radius would be smaller. I'm not saying a surface detonation would be a good thing, but that it is much preferred to a high altitude blast where the effects will go for thousands of miles.

Re:NO, NO, NO, NO, this is a BAD idea

[brambus]

Nuclear powered craft are ONLY used for spacecraft which will be leaving earth orbit and not returning.

Those nuclear reactor powered probes I mentioned (SNAP-10A and TOPAZ reactor series) are in orbit. But I see what you mean and in Earth orbit, solar power seems to be good enough for most use cases.

First, you can physically render a nuclear device inert by removing parts of it.

Of course you can. All you need to do is distort any part of its ignition mechanism. You could do that on orbit even.

I believe they call it a "pill"

Precisely. It's usually a central part of the first stage. Without it in, upon ignitor detonation, the nuclear material won't compress correctly and will instead tend to be flung out of the pit, rather than achieve criticality.

So keep your nuclear devices UNDER ground, keep them disabled by storing that last bit of fissionable material in a totally different area.

And this is precisely what we already do and what even this asteroid defense plan would do.

Setting a device off in LEO is going to be a mess and it's going to affect a huge area.

The points on EMP blasts and radiation damage on detonation in LEO is quite correct. In no case would asteroid defense, however, entail doing that. By the time the object got close enough for LEO detonation to be a factor, we're toast anyway. A few seconds to minutes to impact - no amount of nuking is going to turn an asteroid around or stop it dead in its tracks. Asteroid defense always talks about deflection when the object is very far away, way past the orbit of Mars even. I think you got the wrong impression from some shitty Bruce Willis movie :)

Re:NO, NO, NO, NO, this is a BAD idea

[rubycodez]

Vaporizing a part of asteroid with surface detonation or below surface penetrator would produce thrust

Orbiting objects is a solved problem. So is orbiting objects for long period of time.

Soviets did design nuclear weapons that could stay in orbit indefinitely as part of their FOBS system

We have thousands of nuclear weapons in this world on standby, your so-called pit intact and read for arming and launch in minutes.

Surface detonations on earth produce massive amounts of fallout. Those in atmosphere do not. There is a particular range of altitude where EMP is a concern.

Proof of Concept

[lionchild]

Why don't we consider this question after we've gone to Mars and tried it there..or Jupiter perhaps. We should figure out if the idea actually works before we consider deploying it at home, what say? Humans are terribly at risk assessment. We didn't really have a clue what we were unleashing when we set off our first nuclear tests. We did learn quickly...sorta. However, using a nuke against an NEO is something we've only theorized about. We should do some testing. In a place that's not actually remotely near Earth.

bitch, I am wayyyyy ahead of you

[Thud457]

I've got a secret stockpile of rocks and pointy sticks!
You'll keep your thieving pseudopods out of my territory if you know what's good fer ya!

Likely will not happen.

[redwraith94]

So you are going to force China, and Russia to give up the arsenals that they aren't getting rid of? There is really only one way to do that, which would be to destroy them. Nukes are here for the foreseeable future. Let the idea of forcing other people to get rid of something they own out of your mind. The more people that do that, the less likely they will be used.

My favorite idea for getting rid of NEOs is a super powerful laser, that would ablate the surface, and gently nudge the thing off course.

I am sure there are certain scenarios where you could detonate a nuke nearby it, and let the resulting shockwave do the same thing. However the modeling that we have for atmospheric shockwaves is inaccurate, and large object surface will be anything but smooth. Also most celestial objects will be moving much faster than our missiles, so we may not actually have time to intercept them.

I mean no offense to you, OP, however what you purpose isn't possible, that is trimming down the arsenals to only a dozen or so.

A perfect example of this; does Russia still have 152mm nuclear artillery shells? I realize that the were 'destroyed' because of the Start treaty, but I find it very interesting that that is the larger caliber available for the Armata T-14 platform. Which shows another dilemma; can you trust any of the nations that have them to honestly tell you what they have, when first strike capability is so very, very important? They are going to a hell of a-lot of trouble to be able to air-lift 400 tanks to 'anywhere' in the globe (or about 7,000 km) to drop just 400 tanks, which in the scheme of a war with Nato, would be overall fairly useless. Along with having only 80 transports for the entire country is fairly risky. If I were them, that is how I would play it.

As another example, who attempted to 'steal' the nukes via the Minot-Barksdale air base incident? Very few people have the authority to order nukes flown in launch position over the US, in a time of 'peace' (such as that is). Everyone was quietly 'transferred', and no one was court martialed, Which means, that the officers involved in the actual transfer had valid signatures, and they were protecting someone higher up. That's our own country, do you really believe a foreign power is going to be more honest? They won't be, as it isn't the interest of any Government that needs power to enforce its will (i.e., all of them).

Government's are just extensions of the people, and they will behave just like people (i.e. lie to you).

Re:Likely will not happen.

[Anonymous Coward]

Shockwaves aren't going to be very effective in space where the atomic density is so low. For the most part, an explosion next to the NEO will just spraying it with the materials from the bomb and whatever elements in the solar wind happen to be passing by. It'd be more effective to toss up nuclear, depleted-uranium "grenades"

Risk

[Anonymous Coward]

You need to balance the damage caused by an extinction level hit by an asteroid against the higher probability of misuse of a nuke

Re:Risk

[Tuidjy]

An asteroid that can cause an extinction level event will not be stopped by a nuke. It will not even be deflected to any useful amount, even if we had a way to deliver it far enough from Earth, and somehow detonate it exactly where it would do the most damage.

This is as if someone insisted on wearing his 9mm in a bar because it would come in handy when an alien fleet decides to take over Earth.

Re:Risk

[Anonymous Coward]

That depends on how far away it is when the nuke goes off. If we could detect it far enough in advance, then even the little bit of deflection that one or more nukes would give us for an extinction-level asteroid might be enough. Of course, we still don't have a way to detect them soon enough, or get the nukes there, or any other number of technical problems.

Of ALL places, I learned this on /. ... apk

[Anonymous Coward]

A nuke won't work vs. "neo"s in vacuum: No shockwave destructive force results due to no atmosphere.

(Thus, nukes heading towards "neo"s would only "warm them up", NOT destroy them).

* See subject - it made a LOT of sense (think about it).

APK

P.S.=> "It's a wasted day if you don't learn a new thing"... apk

No?

[Anonymous Coward]

If history taught us anything... Is that by the time we detect any near earth object, it's already too late to do anything about it. Until we have a proper planetary defense system that can be activated within 30 seconds, it's too late.

Way Premature - And Probably Unnecessary

[crunchygranola]

There are wide variety of possible cosmic collision threats - with only rare once-a-century (or less frequent) size events being candidates for any sort of deflection scheme. More frequent ones we can absorb with minimal damage. The 2013 Chelyabinsk event was a 20 meter class asteroid, and we get hit with a few of these a year. Even a repeat of the Chelyabinsk over a much larger city would not be catastrophic, as a natural catastrophe it might rank as a "major storm" in terms of damage potential.

It is larger asteroids, above the 20 meter size, that are destructive enough to consider an international interception mission.

Barringer Crater in Arizona is an example of a 50 meter object (a once in a millennium event), such an impact would be highly destructive in a populated area. Current collision threat programs have identified 96% of the "civilization ender" 1+ km class objects (once in a million year event), and are moving toward identifying 90% of the 140 meter class (once in 10,000 years).

The ideal method dog dealing with any collision threat is to detect it long in advance, accurately measure its trajectory, and then modify it just enough to avoid a predicted collision years later (perhaps many decades later, even centuries later for really big ones). Smaller objects need smaller nudges and can be diverted at later dates than big ones. An aggressive monitoring system is the first line of defense, without detection there can be no defense, and the better your detection the easier deflection becomes, and the cost of monitoring is much less than a single interception mission.

A variety of nudging techniques have been proposed: kinetic collision diversion, gravity attractor tugs, and nuclear deflection schemes primarily, but all of them are in early stages of development and have some promise. Different deflection schemes might be needed based on the nature of the threat object (size, physical nature, etc.).

Until we have candidate defection systems to evaluate, and actually test, it is way premature to discuss storing nuclear devices for this purpose. Probably storing a ready made device would be of no value. When we detect a threat requiring deflection we would first need to organize the whole launch and space probe project, which would likely take a few years (assuming warning times on the order of decade) during which time a nuclear device customized to the mission could be manufactured as needed. If the world decides (after suitable development and testing) that a ready-to-launch-on-short notice vehicle is a good idea to deal with small threats detected months in advance, and it is determined that a nuclear device is the proper technique, then we would only need one such system to be built and kept ready - with a grand total of one special purpose nuclear device.

Re:Way Premature - And Probably Unnecessary

[CrimsonAvenger]

and it is determined that a nuclear device is the proper technique, then we would only need one such system to be built and kept ready - with a grand total of one special purpose nuclear device.

I like the way you assume nothing could possibly go wrong with your single launch. Be a shame to have one special purpose nuclear device fall onto the moon because the launch vehicle screwed up....

Trust me. Don't build special purpose devices (which require testing in any case), and don't just keep one around. Keep enough that you can recover from a launch pad error and an Apollo 13-style error and a brand new kind of screw up ....

Re:Way Premature - And Probably Unnecessary

[crunchygranola]

Actually I should have simply said that only "one system be kept ready", not that only one should be built. So make it two, even three for back-up. Well established launch systems have reliability rates of 95%, so high levels of redundancy are not really called for. Still not 10-20. And it still only is needed for one corner case of relatively small threat magnitude. More serious threat call for special missions and have threat timelines long enough to organize them.

Actually testing the interception system was stipulated, but having tested it, you know how to build more.

Shouldn't we first...

[Dcnjoe60]

Shouldn't we first determine if nuclear weapons would even be effective against a NEO before asking if we should keep them on hand?

two schools of thought rear their ugly heads

[nimbius]

There are two approaches the article betrays through its conjecture...neither are feasible entirely
destruction/annihilation: although our arsenal is massive, it is dwarfed by shear size and velocity alone of the objects most are considering hazardous. firing a pyrric volley would fragment the NEO, resulting in a clusterbomb effect of partially radioactive high velocity material, and highly radioactive fallout in most cases. the shockwave from the blasts would be felt in all directions and all objects, including our cities. the EMP would also be a sizeable consideration. fun science fact: this was our solution to russian ICBM's in the cold war. that our missiles would blanket major cities in moderate fallout, but prevent an ICBM from landing. it was purile at best.

Deflection:possibly, but into what or where? with no guarantee the object would become less dangerous in numerous quantities or into how many masses it would fissure into, this is just a hail mary. Very small objects could be obliterated using conventional ballistics but, again, its a technology we employ to eradicate old satellites as a show of military force...not a nuclear option.

TL;DR: nuclear retalliation is a powerful, but awful idea that would result in debilitating destruction of satellites, hazardous fallout, and a loosely based plotline to the next bethesda video game.

Re:two schools of thought rear their ugly heads

[crunchygranola]

Deflection:possibly, but into what or where?

Easy: away from Earth. It is only the fact that at one point in its multi-billion year orbital history that it happens to come within 4000 miles of the Earth's center of mass that we care about. If we make it miss, by even a small distance, it will continue (typically) for billions of years more.

Asteroid deflections is really just a process of cosmic sheepherding - keeping the orbits of the big rocks from becoming (and remaining) Earth intercepting ones.

Re:Of ALL places, I learned this on /. ... apk

[Anonymous Coward]

Too bad what you learned was wrong.

Assumptions?

[nitehawk214]

Is this guy assuming we will eventually eliminate all of the thousands of nuclear weapons we currently have? What in the world does the poster mean by "on hand"?

The article's title is "Should nuclear devices be used to stop asteroids?". Makes me wonder if the submitter read TFA.

The article itself is kind of dumb. It talks about rethinking the Outer Space Treaty that bans nuclear weapons in space. If there was a global threat on the way, the time it would take to arm and configure a rocket to send the weapon to the asteroid would be insignificant. If the asteroid is close enough that something sitting in, say, geostationary orbit could touch it, we would all be dead. In fact, if the threat was any closer than a year from impact, no amount of nuclear weapons is going to help us, and we have no rockets capable of reaching an asteroid that far away.

The article writer is naive when it comes to orbital mechanics, the staggering kinetic energy of a significant asteroid, and that these guys actually have a chance at getting all nuclear weapons banned.

Re:Assumptions?

[david_thornley]

Seems to me that, if we have time to design and build a rocket to deliver a heavy payload to exactly the right place, we have time to put together a few nukes. We've known how to build these things for a long time.

Interesting.

[stoned_ritual]

What about flying a swarm of drone-like propulsion engines that can attach to an NEO and push it in a direction with thrusters?

Burying the lede

[PopeRatzo]

The first question regarding what to do if a giant meteorite is heading for collision with Earth should be, "Is humanity worth saving?"

Let's start by making a list of reasons why it's important to save humanity. And I'm sorry, "Because it's us!" is not persuasive. Who wants to go first?

Nuke it from orbit...

[Irate Engineer]

..it's the only way to be...wait, oh damn, that won't work.

Never mind.

I keep one in my glove box

[Anonymous Coward]

traffic jams are a bitch.

10 or 20 nuclear devices?

[friesofdoom]

Is he implying that there aren't already (and will probably always be) at least 10 or 20 nuclear devices laying around that would do this job perfectly?

I'll take a read, & am willing to listen

[Anonymous Coward]

What was said made sense (no compressed atmosphere = no destructive shockwave) though - BUT, see subject...

Just *might* be I was right suggesting using our nuclear arsenals for CONSTRUCTIVE DESTRUCTIVE purposes vs. asteroids that threaten us... we'll see. I'll "drink it in & digest it"...

APK

P.S.=> Thank you... apk

Just call Bruce!

[kimgkimg]

Certainly Bruce Willis should always be on-call...

What about the EMP?

[DMJC]

Has anyone studied what a nuke detonated against an NEO would do with the EMP? Sure we might stop the object but the EMP could be almost as bad in its effects on life on the ground.

Re:What about the EMP?

[david_thornley]

If the detonation is anywhere near close enough for the EMP to be detected, it's too late to deflect the NEO and we're screwed anyway. The idea is to detect the impending collision with months or years to spare, and nuke the NEO in deep space.

But what about The Donald?

[Anonymous Coward]

When the Whack Jobs elect Donald Trump I pretty sure don't want for there to be ANY nukes left!!!

Orion is the best counter for large incoming mass.

[dweller_below]

If you actually want to effectively counter the "Dinosaur Killer" scenario, the best answer is early detection and a large "Orion" ship. See: https://en.wikipedia.org/wiki/...

We could have build a large Orion propulsion ship anytime in the last 40 years. It would probably cost less than an aircraft carrier. A large Orion propulsion ship could get almost anywhere in the inner solar system in a few weeks. And the propulsion system will work just fine to redirect another large mass. Yes, there will be a bunch of fallout damage from the initial take-off, but we can decide where to place it. and the fallout damage from Orion's propulsion is tiny compared to the damage from an asteroid strike.

I have always hoped that there was a secret plan to convert our offensive arsenal into Orion propulsion if the need occurred.

In other news....

[Dutchmaan]

... major league baseball is pondering on whether or not to use advanced bottle rockets to deflect incoming baseballs from colliding with batters!

Efforts exist for dealing with this issue

[CyclistOne]

See http://sentinelmission.org/ for info on an organization already addressing the issue of NEOs. Also, former astronaut, Rusty Schweickart, gave an excellent talk on this at the Long Now Foundation. I believe an .mp3 file of the talk can be downloaded for free from the Long Now website.

It depends.

[Trax3001BBS]

I've worked in the nuclear field producing Plutonium and what would be used in the war heads.

No.

But as a disclaimer, a lot of variables would need to be considered first, it's not really a yes or no answer.

Should we make saddles for dinosaurs?

[Anonymous Coward]

It's a similarly stupid question that presumes a situation that will never exist - President Obama is currently making sure the world will have hundreds of thousands of nuclear weapons on hand. The fantasy that nukes could ever be eliminated was abandoned long ago by serious people, but now even the post-cold war levels of severely reduced nuclear weapons are going to be a distant memory.

President Obama's biggest legacy will be the permanent elimination of nuclear arms control.

By actually enabling the Iranian nuke program (rather than actively stopping it as he pledged to do) and by doing NOTHING to reign-in the Pakistani and North Korean programs, and by backing-down in the face of every single Russian and Chinese military intimidation (including Putin's new pledge to violate the current ICBM arms limits and his current violation of the IRBM limits) Obama is destroying the credibility of the idea that the US or NATO will enforce ANY nuclear weapons treaties or the Non Proliferation Treaty. If he cravenly signs-onto the Iranian deal, which reports say abandons all the strict monitoring he originally said he had to have, there will be a mideast nuclear arms race and all the nations on Earth will be on-notice that no arms proliferation treaties are dead.

The upside of this insanity is that we will have plenty of nukes to deal with any asteroids, assuming we do not use them all in a nuclear war triggered by a mad mullah who believes he can summon his God with a global massacre (a popular belief among the twelvers in Iran).

Re:Orion is the best counter for large incoming ma

[heteromonomer]

Oh for mod points.

Yes, they train "those guys" in that.

[tlambert]

Now you're down to trusting the rational decision-making of a low-level grunt who's been stuck below-ground in a silo, watching every day for the launch order to come down. You think they train those guys to be skeptical of the orders they're given?

Yes, they train "those guys" in that.

The specific class at the United States Air Force Academy in which the train them in this is Law 220, and the unit within this course is called "Military Dissent and Junior Officers", and they are taught how to properly respond to illegal orders. Without a declaration of war, which requires the approval of congress, and without it being a retaliatory strike for an exiting strike in progress, the order would be illegal.

In case you were wondering, Law 220 is a Core Course, and passing it is a requirement for graduation from the USAF academy, which is itself a requirement for becoming a commissioned officer qualified to act as a "missile jockey".

But I think if the president were to issue such an order without a clear and present threat, it's more likely that it would not come down to the missile jockey; instead, he'd be wrestled to the floor by his senior cabinet, followed by anything ranging from a "The president is gravely ill" to a "The president tripped and fell on his letter opener" announcement, to explain why he was no longer presidenting.

I'm pretty sure the same would apply in Russia, China, and North Korea.

Re:Yes, they train "those guys" in that.

[PopeRatzo]

The specific class at the United States Air Force Academy in which the train them in this is Law 220

Is that class before or after the required fundamentalist Christian dominionist prayer meeting?

http://www.truth-out.org/opini...

But I think if the president were to issue such an order without a clear and present threat, it's more likely that it would not come down to the missile jockey; instead, he'd be wrestled to the floor by his senior cabinet

Do you remember any of the people in the Bush Senior cabinet? The Reagan senior cabinet? You're really prepared to trust that all these people and all future cabinet members are always going to be rational?

Re:Yes, they train "those guys" in that.

[tlambert]

Do you remember any of the people in the Bush Senior cabinet? The Reagan senior cabinet? You're really prepared to trust that all these people and all future cabinet members are always going to be rational?

Nope. But I don't have to. Just like I don't trust all countries to be rational actors, all it takes is enough of them to stomp on the ones that aren't. And yes, I trust the bulk of them to be rational actors, and that's really all it takes. Even were that not the case, we always have anyone in the SAC-NORAD chain of command down to the Lt. playing cards with the other Lt. in the MCC for the duration of their 24 hour tour.

Ha ha ha ha.....

[argStyopa]

The question posed by the OP presupposes that nuclear weapons might otherwise be 'going away' which is such an intrinsically naive and unrealistic proposition that I immediately comprehend whatever subsequently comes from the author's mouth as laughably insane and worthly of little regard.

We already are

[borknado]

The U.S. most certainly already has a store of nuclear tipped rockets meant for leaving Earth orbit precisely for this threat. Most people don't understand that this is what fundamentally differentiates us from all other living organisms in history and all our previous generations - we are are aware of and are able to defend ourselves against asteroids and comets, which are able to end entire biospheres and everything in it.

Because...

[DarthVain]

I'M BATMAN!

When will the idiocy stop??!?

[Anonymous Coward]

Real life physics DOES NOT work like the movies. The movies are epic fail for learning physics.

In general, nuclear weapons will not help deal with "asteroids and comets" if they happen to be on an intercept course with the earth.

Get this through you stupid thick head!!

Question: How's it taste "eating your words"?

[Anonymous Coward]

See subject & answer it vs. you doing it here http://tech.slashdot.org/comme... so keep "puffing that pot" fool!

* :)

Gotta love it - seeing you give me guff (yet being a "ne'er-do-well" pothead with nothing better to show for yourself vs. what I've done that gives others more speed, security, reliability, & anonymity), knowing you CRIPPLE your OWN thought processes with pot is priceless, since it makes it (& I've just GOTTA say it, you're making me do it) "too, Too, TOO EASY - just '2ez'" to utterly crush you by making you "eat your words", spiced with the bitter taste of SELF-defeat, + your foot in your mouth RAMMING THEM DOWN, rinsing down the puke you spewed on /. that I smacked you down with easily!

APK

P.S.=> Gotta LOVE pot smoking dolts - they're stupid enough to do what "stoned_ritual" did, & smash themselves into the ground everytime vs. myself, lol... apk