Slashdot Mirror
Assessing Asteroid Threat
Makarand writes "According to a proposal submitted to
the European Space Agency a fleet of
five mini-probes
should be sent each targeting an asteroid
considered potentially dangerous.
The mission objective will be to learn more about dangerous near earth objects so that we can plan how best to respond when under threat.
Once in space, the probes would use ion propulsion engines that provide thrust by shooting out a stream of electrically
charged particles. Power for the ion engines would be provided by ultra-lightweight solar arrays.
Each probe will carry instrumentation to learn about the physical and chemical make-up of the target. The mission would cost around $150 mil
which is quite low according to space mission standards."
After watching the news or reading a paper, I find myself rooting for the asteroids.
--- Ban humanity.
I am not worried, Bruce Willis will save us.
However, it is more like $160m.. not $150m in USD. 159,972,995.78 USD to be exact, as stated by http://www.xe.com/ucc.
I thought I fixed this problem years ago with my Atari!
"I only speak the truth"
Karma: null(Mostly affected by an unassigned variable)
Only an optimist wuld believe that the U.N would commit to a path of aggression, until all diplomatic options had been exhausted. The asteroids must be convinced to disarm themselves.
It's supposed to be completely automatic, but actually you have to press this button.
Some VC has a Neat Idea, which nobody wants. Is that his fault, no! Who will buy it - Governments, they can print as much money as they need. Of course this was done in Europe, their monopoly-money machines work better than in the US (Russia has no money, monopoly or otherwise).
Here's how you really get rid of an asteroid:
Insert used ICBM into Space Shuttle (or equivalent)
Place ICBM and suitable launch device into LOE.
Aim ICBM at the place where the asteroid will be when it gets there.
Press the button that we've wanted to push for so long. Sell tickets, I'm sure the Russians would want to attend - maybe a joint "button pushing" ceremony? Heck, bring the Chinese and N.Koreans in too.
Watch as ICBM blows up asteroid.
Profit!
(Part where it ushers in a new sense of global peace and brotherhood is optional)
I want to delete my account but Slashdot doesn't allow it.
if they spot one heading for us the space elevator idea will suddenly seem extremely plausible
Do not try to read the dupe, thats impossible. Instead, only try to realize the truth
What truth?
There is no dupe
Here in the UK there was a TV documentary (probably BBC2 Horizon, not sure) about asteroid impacts, how to deal with them and so on. I for one thought it was much like Arthur C Clarke's Hammer of God - find it early, deliver an impulse, deflect it a teeny weeny bit, and it misses by a few miles. Nope. The asteroid could be very porous, it just absorbs the blast, or requires an impossibly big bang to be sure it deflects. So sending probes to gather facts about asteroid composition is a good and useful practical thing over and above the scientific justification.
That's no asteroid. It's a giant Space Potato!
Read any good sonnets lately?
Like the one seen here. :)
...NASA proposes a $300 million project to build a gigantic "Welcome to Earth! We value our children, please abduct safely!" sign on the moon. This is to remind alien vacationers (who come speedin' down that local group highway like nobody's business) to slow down a spell, and think carefully before they start carrying off our kids and probing them.
Seriously, does anyone else think this is a waste of resources? Give that $150 million to Highlift for Pete's sake...
Seriously, when did you first hear about dirty bombs and Asteroids that would kill us all?
Shortly after the 'end?' of the cold war.
All that got swept under the carpet when the axis of evil decended upon the earth(though the dirty bomb's popped it's head up again).
thank God the internet isn't a human right.
That is the raw translation of a hungarian novel written in the early 80's.
It takes place in the near future when the Earth population is 10 billion. An asteroid threatens Earth, but so big nothing can be done just one thing. By calculating the trajectory of the asteriod the engineers notice that it nearly collide another, but smaller asteroid.
So, they send up a spaceship with full of explosives and ram it into the small asteroid in order to give it a push which is sufficient to make it collide with the big one.
Billiard on the cosmic scale. And it was written well before the public became aware of the asteriod threat.
Government cannot make man richer, but it can make him poorer. - Ludwig von Mises
Each Simone spacecraft will have instruments designed to examine the physical and chemical make-up of its target asteroid. It is hoped the missions will help scientists predict the risk posed by asteroids and develop effective strategies for dealing with different types of object.
What properties, other than mass and trajectory, are of interest? It's not like they're going to find harmless ones made out of rubber or whatever.
Pretty smart using Simon to stop the asteroid... "Simon says jump on one foot. Simon says don't hit the Earth..."
Next on /. how to save Earth from an Alien attack using the Hockey-Pockey
"There is no teacher but the enemy."-Mazer Rackham
IMO, is that an asteroid that's on a collision course for Earth has been detected and they're leaking it in various ways to news reporters.
not from the heavens, but from the human beings on the planet.
Why do we worry about these thing when the population of this planet can't even figure out how to deal with the threats on this planet that we have control over?
"Oh, you hate your job? There's a support group for that, it's called everyone, they meet at the bar."
Deep Space 1 (DS1) was the first probe to use ion propulsion. There were 12 other advanced technology used on that probe. You can find more here.
Government cannot make man richer, but it can make him poorer. - Ludwig von Mises
This years scientific focus is eliminating bad jokes on late night TV.
You may think me a tired, old, cynic. I'd have to disagree about the tired bit.
We really shouldn't worry about things like this until we have to.
By the time we have to worry about it, we are all already dead. Not just those of us with cancer or AIDS. That's like saying you shouldn't worry about a computer virus until you get one. You shouldn't worry about security until your server is rooted. You shouldn't worry about your car until the engine seizes up.
Random is the New Order.
Now, one might argue that if we knew things like chemical make up or density or the like we might know how to destroy the object or perhaps could change it's trajectory with engines or a tractor beam or something. However, this implies that we know the object exists with enough advance notice to do something. To plan a research encounter, that might be a year. To plan a destructive encounter, I think that might be a month. I seem to remember that the in the last near miss, we did not detect the object until after it had passed.
Which is to say that we need better detection technology coupled with serious research of how to change trajectory. I do not believe converting a single projectile into hundred of projectiles is a reasonable solution. And of course, if we don't know the object is coming, there is nothing we can do
"She's a scientist and a lesbian. She's not going to let it slide." Orphan Black
"Why Jupiter, who's size compared to Earth is immense, has not had a large asteroid annihalate it yet? (ok, maybe it has, i don't know)"
It has been hit, very spectacularly, had it been Earth that was hit I doubt we would be discussing this.
See:
Comet Shoemaker-Levy Collision with Jupiter
That sounds an awful lot like what the Global Warming folks do.
_ _ _ Go for the eyes Boo! GO FOR THE EYES!
Instead of changing the orbit of the asteroid, why not simply change the orbit of the earth. All that is needed is the entire Chinese population jumping. Once we have safely avoided the asteroid, someone on the other side of the earth can nudge it back in place with some additional jumping, we might even improve the orbit a tad while we're at it. Obviously this is cheaper, more enviroment friendly and whole lot more "down to earth" than the proposed ICBM plans.
Rest in peace Malin "looxn" Kristiansen. We miss you...
So everyone is making jokes about the topic, but wasn't there this story about this asteroid that would get close to earth somewhere in 2016 or so (can't remember the year), and that would raise the temperature of the earth to 50 degrees celsius at the moment it passes by? Or was that story declared invalid later on?
"We can confirm that Debian does *not* ship the version with the trojan horse. Our version predates it." [CA-2002-28]
How many of these fucking articles are we going to have to endure before everyone realizes A) there is no threat, and B) even if there was one, we are absolutely powerless to do anything about it as a species that would make a damn bit of difference?
How do you know unless you've assessed the threat? Are you willing to bet possibly the entire earth's population on it? $150 million is nothing compared to the money spent on making cars safer.
I doubt that there will be anything significant that we will be able to do except predict the end of the world, and you bet that I'll be quitting my job then! :)
If the earth was going to be wiped out it might be a good idea to try an set humanity up somewhere else. There are of course 2 problems w/ this; 1)this would cause a reverse natural selection effect as inbred Texans would be first to safety, and 2)right now our solution to living in space consist of shipping things from the surface, not recycling what we already have up there
If we could start a stable biosphere in orbit we could have set up a colony to last an indefanent amount of time on the moon or other body
Don't save your orgasms for Heaven; Heaven knows we need them here.
Trouble is, they come back down again, negating the effect. Better to get some large population to all face the same way, then fart. Muslims would be ideal. Issue them with cigarette lighters for a larger deflection.
... the asteroid is a cylinder ? are we gonna blast it too ?
*has read too much A.C.Clarke and / or Greg Bear*
Tsuyoikoto ha taisetsu da ne, dakedo namida mo hitsuyousa (Strength is an important thing, but tears too are necessary)
Principally, how physically strong is the object.
If it's strong enough, perhaps like a nickel-iron object, perhaps the best way to deflect it is with explosives.
If it's weak enough, perhaps explosives could blast it to smithereens, all small enough to burn up in the atmosphere. This would also indicate that it's time to get together and work up an exception to the "no nukes in space" treaty.
If it's somewhere in between, then it's time to ship some sort of rocket engine up there to move it. In that case we have to question just how much thrust it can structurally take before it breaks into pieces, leaving our engine shooting off into nowhere.
The living have better things to do than to continue hating the dead.
$150 million to explore the REAL dangers of space is cheap at twice the price.
"Learning is not compulsory... neither is survival."
--Dr.W.Edwards Deming
While this research may well give us some miscellaneous bonus research regarding asteroids and such, it seems slightly fruitless.
Yes, there is a chance an asteroid will hit us. There's also a chance black hole will spring up next to us and suck us in. There's even a tiny chance that the sun will extinguish itself leaving us with the task of trying to reignite it.
Why waste money on such research which will, inevitably, be pretty useless when (and if) an asteroid the size of Britain comes along our way.
I think these guys have finally got around to renting Armaggedon and got a little paranoid.
We really shouldn't worry about things like this until we have to.
You are assuming that WARNING_TIME > DEVELOPMENT_TIME. That's a very dangerous gamble. Sure, cancer kills a lot of people, but it isn't going to kill everyone.
to make fuel and infrastructure from materials already in space
I hope to see that happen in my lifetime - even if permanent.com is too optimistic. That's why I like these probes, not because of the (negligible) impact danger.
Any sufficiently advanced libertarian utopia is indistinguishable from government.
There must be some range of size that is too big to ignore and small enough to do something about. So why not?
in such case we need a mass drivers, something like a robotic mine installed on the surface of asteroid, which throws digged ore through electromagnetic linear accelerator. unfortunately, this option was found by The Hollywood as unworthy and too boring to make a movie with superhero, so we will be doomed
(transmissions from the end of the world will be prime-time for advertisement :))
Once in space, the probes would use ion propulsion engines that provide thrust by shooting out a stream of electrically charged particles. Power for the ion engines would be provided by ultra-lightweight solar arrays.
Hmmmm....so, a pair of flat, lightweight solar arrays. I betcha you'd have to mount the ion engines in parallel, to keep the thing from spinning uncontrollably. And a center sensor/instrumentation package...
Why does this sound familiar?
El riesgo vive siempre!
You are joking, right?
To borrow your own analogy - "So we have proof that the server has been rooted in the past, but no solid proof that it can, or will, happen again. Until we find that proof, let's not waste money on a firewall".
-- And when Justice is gone, there is always... Force. --Laurie Anderson, "Oh Superman"
Considering the amount of money spent on practising for war every year - "defense", the proposal to the EU is peanuts. It is a proposal to start investigating the possibilities of a very real threat. I seem to recall the Siberian meteor impact as estimated as equivalent to about a 30MT H-bomb, and we were very lucky it hit where it did. It also seems that satellite photography is identifying more and more impact sites on the Earth. When I was a kid very few of these were recognised, and it seems reasonable to me that if we are learning that the frequency of such hits is much higher than expected, we should start to do something.
It's also worth remembering that the big impact on Jupiter occurred only a few years ago, and that very visible impact may well have concentrated people's minds. As telescopes get better, astronomers are realising there is far more debris out there than anybody knew- the old idea of 9 tidy planets and an asteroid belt has turned into a solar system full of all kinds of junk, moonlets, comet formation belts- the Solar System seems to be more like Mexico City than Singapore, if you see what I mean.
A billion dollars sound like a lot, but how much is the ABM system going to cost?
Dealing with a hard rock or a dirty snowball could need very different approaches (gentle push versus big bang?). Just because a multi-mile wide asteroid could be undeflectable and fatal, doesn;t mean that the real threat might come from a thing 100M across - obviously deflectable with the right technology, but nuking it could result in thousands of destructive small impacts.
To sum up this ramble:
- Destructive meteor impacts do occur on Earth
- Some of them are potentially preventable
- The cost of research is probably going to be far less than the US is going to spend developing nuclear warheads this year
- The cost of stopping a small asteroid could be a lot less than the estimated budget for stopping Saddam Hussein
- All in all, it looks far from a waste of EU money.
Thank you for reading this far.Panurge has posted for the last time. Thanks for the positive moderations.
Its not pointless at all.
/. article about that idea bout 6 monthes ago.
:-) However they are that fragile that they will be realy hard to get rid of them. A steam rocket might be suitable but also it might just not stick on the body because of the fragility.
... to attach solar sails or steam rockets on it.
...
There are plenty of ways to alter the course of an asteroid.
E.g. if there are gases, or frozen liquids on such a thing you could try to use a steam rocket.
Solar power heats the stuff up and uses the gases like in a rocket engine.
You could try to alter the albedo/colour by painting the surface. There was a
Far more interesting is the attempt to put solar sails on it, to drag it away, however such a asteroid will be rotating somehow. Rotation would be needed to stop, or a way needs to be found to tackle a rotating asteroid.
Lasers could be used, not like in Star Wars but as constant pressure, instead of solar sails, to push it away(of course we would need a laser on the moon for that or in space).
I could imagine there are hundrets of concepts thinkable but ony a few will suit a specific asteroid.
Also: not only asteroids are a problem, comets as well. But those are more rare and more easy to spot
So a giant net, wrapped around the asteroid might be usefull
How to manufactor them, probably with resources on the body itself
Pleanty of questions. Plenty of reason to go and look.
angel'o'sphere
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
We have proof that asteroids have hit the Earth in the past, but no solid proof that it can, or will, happen again. Until we can find that proof, let's stop wasting time on projects like this.
Well, why don't you read more
The last near miss was only 3 times farer away than moon. It also was only less than 6 monthes ago.
Yes it was a near miss, not a near hit
Near not in the sense of "nearly" but in the sense of "close by".
Unfortunatly with our current way of handling this issue we will get the information of a impact only some monthes before it will happen.
Probbly you conclude from that that there is no proof.
angel'o'sphere
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
But, I think that research with world-spanning possibilities (cancer or AIDS cures, prevention of a "killer asteroid", etc.) should be funded by everyone, and the scientists should work for only a reasonable fee, and shouldn't use money as their primary motivating factor.
So, your position is that only those who market trivial consumer products should be able to make a lot of money?
I am reading this book (or well... listening to the audiobook version) right now.. combined with these slasdot news it is alarming! do we really have ANY possibility to escape extinction if we get it??
Doesn't it make sense to cover as many different threats as possible?
Imagine: we finally solve all or most of the earth's problems that we have control over. But then an asteroid hits and it's all for naught.
What's wrong with concurrent develpment of solutions to possible threats?
Well, we know that asteroid impacts are unsafe at any speed. I think that Congress should mandate airbags on asteroids. Just think of it, when the next Siberian asteroid hits, you'll just hear an explosive "THWUP!", and large sections of remote forest will be gently flattened by a big inflated cushion.
Next, we'll have NBC panic-mongering about the federal asteroid impact research scene by rigging tests with Saturn V rocket boosters hidden on the things. "See how it explodes on impact?"
Maybe, when we have warm fuzzies about the North Koreans again, we can get one of the things classified as a replacement 'axis of evil' member.
In any case all this running around yelling about the asteroid threat is pretty misplaced, thanks to the helpful tips from the department of homeland security (duck tape all your windows! Stock up on gummi bears!)
As an American citizen, I feel pretty safe from the things, anyway--it doesn't at all fit into my way of life (nobody to sue if one hits, really.)
On the other hand, if we ever catch wind that one's going to hit L.A., we can convince some of the locals that they're aliens on a mission of peace, so they'll go stand directly under it, waving signs that read "welcome to earth!". Should cushion the impact a bit. Or maybe we'll just issue Powerbooks to every wild-eyed scientists out there--that'll let them completely scramble the asteroid's central computer and cause it to self-destruct.
In any case, even if it takes out half the planet, it won't be that serious. After all, the internet is designed to route around the occasional localized outage; as long as I can still get my morning comics online, all's well in my world.
Cole's Law: Thinly sliced cabbage
... they want to send inspectors first to make certain the asteroids are *really* a threat.
Get off my virtual lawn, you damned virtual kids!
What happend to the Dinosaurs on your planet, Bowie?
-- And when Justice is gone, there is always... Force. --Laurie Anderson, "Oh Superman"
We already know that there are a lot of objects in space which are powerful enough to cause a 10 megaton explosion but which we will not be able to see until they enter the atmosphere. Now, back in 1908 when one hit us, it hit us in a remote area so not many people in the world knew about (except, of course, those unfortunate people who where within a couple tens of miles of it when it struck.) But nowadays, EVERYONE would IMMEDIATELY know that an explosion as powerful as a nuclear weapon had just gone off in their back yard, and there's a good chance that they would immediately retaliate against whoever they thought launched it.
Wouldn't it be ironic if we helped an incoming asteroid finish us off, rather than hindering it?
Snarkiness is inversely proportional to wisdom because it emphasizes feeling right rather than being right.
Well, that's what we'll tell him. ;)
-- And when Justice is gone, there is always... Force. --Laurie Anderson, "Oh Superman"
I found a website here which has specifications for a space vehicle with dual ion engines and solar arrays to power them. This one is manned, too.
RTFM; please, I beg you.
That's right. We already know asteroids are deadly...even small ones. Look at the meteor that hit Arizona. Or, how about the supposed comet, yea just ice, that hit Tunguska in 1908.
Asteroids aren't very likely to be made of "sponge" matter. There is a good bit of variation in their makeup, but on the whole, anything a few thousand feet wide or more will have a devastating impact.
Also, it is very unlikely that we can get an acceptable "makeup" of the asteroid just by landing in one spot. That's like taking a pole in Florida about whether Floridian's like Bush. You really need to drill...deep.
Frankly, I'd rather give my money to SETI. But the smart thing to do is to go ahead and put that money into the investment of what we WILL do when we find a killer asteroid.
So what if we find out exactly what the asteroids are made of that we send the probes to. Chance would have it that the one that hits us will be made of solid iron. If you are going to spend any money at all, spend it on preparations for the worst case. Anything else is just a waste.
+2 cents contributed.
ESA was talking about this project (and five other) in September of last year.
See this link for a little information on them all, and some background gumf.
Actually it is rocket science...
"The mission objective will be to learn more about dangerous near earth objects so that we can plan how best to respond when under threat." ...can a near earth object really do harm to us? I mean really? Shouldn't it be quite obvious that they're going to smash into earth, boiling seas, causing tremendous tsunamis, earthquakes the likes of which have never been seen and never again will be seen by humans? Let me guess, the French proposed this "diplomatic" solution to try to talk the asteroids out of smashing into Earth. I'd rather see that $150 million invested into ways to destroy an asteroid before it becomes a serious threat.
We have proof that asteroids have hit the Earth in the past, but no solid proof that it can, or will, happen again. Until we can find that proof, let's stop wasting time on projects like this.
Gosh, you're so right... After all, Slammer nailed a bunch of computers, but that was in the past, and there's no solid proof that any virus or worm ever will occur again! Until we can find that proof, let's stop wasting time on firewalls and security.
Thing is, if we detect an asteroid with current technology, we might have only a few months warning - as it currently takes a minimum of about 6 weeks of preparation to launch a _single_ shuttle, what do you think we're going to be able to do to deflect an asteroid?
By the time we find out about one, it's probably going to be too late to start thinking about plans to stop it.
-T
For several reasons. The primary, of course, is so we know what methods will work best for moving the asteroid's orbit enough so it doesn't hit. Secondly, knowing it's composition will allow us to better estimate it's effect. A mostly silicon (sand-ball) asteroid will have different impact characteristics than a lead/iron 'bullet'.
I don't read AC A human right
--sex
Very popular slashdot journal for adul
Ummm... no. Over time Jupiter and Saturn's gravity knock asteroids which are happily orbiting in the asteroid belt into earth-crossing orbits.
So because we haven't had a planet killer asteroid impact in 300,000 years means that we're in the clear? I'll have to take that logic to the craps table next time I'm in Vegas. "Well, haven't seen a 7 in 5 rolls, they must not exist!".
And besides "earth killer" impacts, we are susceptable to impacts which can cause "serious regional damage" about once per century. I for one am glad that some rational people are "obsessing" over it.
According the the site, there's been 5 major asteroid extinction events since 'primitive fish'. A quick eyeball says that one of these happens ~50 million years. We're at 65 million right now, and we've entered the period for stuff captured when we passed through the thick part of our spiral arm to be coming in.
And don't forget June 30, 1908, where an asteroid,
I think I'd rather not suffer an 'asteroid winter' if we could have prevented it by knocking some of these smaller asteroids out. And I'd also like to prevent an impact similar to Siberia's.
I don't read AC A human right
Not quite. Several nuclear-strength detonations occur each year in our upper atmosphere from meteors. NORAD is quite good at telling the difference.
You can tell a great deal about the character of a man by observing those who hate him.
Control is an illusion. The only thing that you can control is yourself. And even that is quite difficult.
It seems to me that an asteroid, lacking free will, is easier to control than any group of people.
It's not really based on hard evidence except what I've seen of meteorites in museums. Basically I think that when these probes are sent they'll find that asteroids are in fact made of rock.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
Seriously, how long before Taco Bell puts that sign out in the ocean again, so everyone gets free tacos if the asteroid or Planet X hits it?
Netjak.com independent reviews of domestic & import video ga
Maybe it needs to be demolished to make way for a hyperspace bypass.
Think For Yourself, Question Authority - Timothy Leary
Good point.
Also worth noting is that "al" is the Arabic equivalent to the English word "the". So a sentence that includes the phrase "the al Queda cells" is redundant.
Algorithm, altitude, alcohol are words English has borrowed from Arabic.
There was a recent article about a similar sized probe, designed solely to inspect satellites for external damage. It will cost $60 millkion a pop. So I am highly skeptical that these probes, which will include a brand new ion engine, will cost just $30 million.
You can't deflect a meteor much by crashing NASA probes into it. I suppose that's why they're looking at it in Europe.
Not that this wasn't entirely predictable.
Is it not possible, if you can make an explosion powerful enough to generate enough heat, to actually vaporize an asteroid? If so, a 'large blast' may be the answer, but only when we have developed weapons several orders more powerful than the most powerful ones we have today. The asteroid could be melted and dispersed in all directions if we could generate a powerful (and hot) enough blast, ya know one similar to what would happen if the thing went into the sun.
== Jez ==
Do you miss Firefox? Try Pale Moon.
Just for the record, Texas is 266,807 sq miles . Does it make sense to compare a two dimensional item like a state to a three dimensional object like an asteroid? How? Compare the surface area of the asteroid to Texas? 4 pi r^2 is the formula for the area of a sphere.
Maybe one should use the largest cross section? This site says Vesta , the third largest asteroid, is the size of the state of Arizona. This site and this site list some of the larger asteroids.
Let me suggest that the chance of Ceres sneaking up on us is not one in a billion, or one in a trillion. Let me suggest it is zero.
Are there any asteroids the size of US states that haven't been discovered yet? None with Earth crossing orbits.
Are Kuiper Belt Objects asteroids? If so Ceres is no longer the largest asteroid. . But it is even more unlikely that something would divert a Ceres size KBO from past the orbit of Pluto to Earth orbit.
How long would it take to divert an asteroid from an Earth impact? Decades? Centuries? Millenia? Anyhow, Deep Impact had the incoming object be a comet. Even with a project to find deadly NEOs, we could still be snuck up on by a long period or extra-solar comet.
a rogue asteroid if indeed one is headed our way. It's not a matter of IF but WHEN. That's why I've always been adamant about space exploration and development. If such a thing were to happen, granted statistically doubtful, but if it did, we at least, as a species, need to be established elsewhere than earth for any chance at ultimate survival. I say do it.
There is gold in them there asteroids Maby we could strap-on a few ion drives and stear the thing close to the moon and harvest the minerals? lots of problems to overcome but it would be nice to have more rare earth minerals at our disposal.
I don't know, I wasen't here when that happened, It was like that when I got here, Second shift musta done that.
I've heard it proposed (on some Discovery Science program, I believe) that Jupiter, due to it's insane gravitational pull and size, tends to attract quite a lot of the space 'junk' making it's way into the Solar System; absorbing well above it's fair share of impacts.
The point being that we're pretty lucky to have Jupiter out there; protecting us from what could be significantly more hazards making their way into the Earth's orbital path.
The scale of energy released from the previously-mentioned recent collisions with Jupiter just boggles my mind.
Thanks, Jupiter!
Once a threat is identified, it makes no sense to blow it up into pieces because the pieces still would have nearly as devastating effect on the earth as the original monolithic object. That leaves what is probably the best solution: change it's orbit by moving it. How to do that? Build nuclear blast proof parabolic dishes or excavate a parabolic shape on the menacing asteroid's surface and place a nuclear device at the focus and detonate it. The thrust from the blast will deflect the object from hitting Earth. Experimentation, research and computer modeling will need to be done before the efficacy of such an approach can be assessed, and as always, the more lead-time you have in identifying the threat, the better!
BTM
That was the turning point of my life--I went from negative zero to positive zero.
Because it's something we can do something about it, and sooner or later there will be a real threat.
Tech Public Policy stuff
There are several treaties that would proscribe a single nation from militarizing space with nuclear weapons. One is the 1972 Anti-ballistic missile treaty. George W. Bush has already announced that the USA will no longer abide by this treaty.
But I don't believe any one of those treaties would proscribe a truly international effort.
>What is with the obsession of finding solutions to earth/asteroid collisions? ...as time goes by our odds of not getting hit only get better, as Jupiter and the Sun keep sucking up more
You actually answered your own question in a way. Jupiter and the Sun, and to a lesser extent Saturn and Mars, perturb small bodies into a Solar System Pachinko. Some bodies crash into Jupiter/etc., or approach close enough to be thrown effectively into the Sun, or out of the Solar system entirely.
But the vast majority of such encounters are just that, encounters, and the small body continues on a slightly different orbit. We know this because we can trace asteroid families by their geology- "chips off the old block," literally. By mapping the distributions of asteroids by family and current orbit, we can get a handle on orbital dynamics and thus, our odds in this crapshoot.
Unfortunately, asteroid classification needs good spectral data, which aren't that easy to take millions of miles away. And a probe can also check morphology, to see for example if Asteroid X is a single fragment, a pile of related or random fragments, or a parent body itself.
In other words, this project seeks slightly more "basic" science, "why" as opposed to "what's in it for me." Like the difference between watching a sporting event, and getting a blurb of the final score.
>My understanding is that the two most important characteristics that threaten us is that the object has mass and will likely collide with earth. Both of these can be estimated quite well
First, we can't estimate those characteristics that well:
-Mass is derived from brightness, a notoriously unreliable figure. Ice is bright and lightweight, rock is dense and dull, and carbon compounds are dim and soft. We can derive volumes from asteroid occulations of background stars, but this is the cosmic equivalent of Morse code: very slow, very labor-intensive, and only available with significant infrastructure.
We can take a spectrum of the reflected light, but this only tells us what's on the surface, and nothing about porosity. Even so, spectra are difficult to take from dim, fast-moving bodies.
-Orbital parameters are estimates. It takes weeks of optical observations to nail the orbit of one dot on a dotted background. Asteroids are often "lost" when they aren't seen again before the orbit was determined. As the search expands, we're looking for more, dimmer bodies. The central clearinghouse of asteroid data (Smithsonian Astrophysical Observatory) is begging for computers and volunteers for the bookkeeping alone, not even the parameter calculations.
We can add planetary radar to get a firm range, and pin the orbit instantly. Unfortunately, there are very few planetary radars, whose time is extremely limited and valuable. And physically, even the gigawatt-class radar at Goldstone can only reach so far, because photons are now dispersing on both legs of the trip.
Second, the history of a body can be backtracked to thousands of other bodies. Asteroids (and to a lesser extent, comets) are classifiable by orbit and geologic type- we can literally trace chips shattered off parent asteroids. But this requires even finer measurements of spectra and orbit.
A mission to asteroids chosen for "family potential," especially a mission to several such asteroids, tells us how chips have drifted from their parents, and weathered in time. Which tells us which asteroids are likely to be dangerous, and where they might come from.
Think of it this way: you can get sports scores live and for free, but people still pay for tickets. There's an understanding (interactions, behaviors, future potential) that only comes from study, and preferably study over time.
>there's a good chance that they would immediately retaliate
Which is why multinational infrasound networks are being established- the pressure waves of a meteor, nuclear detonation, and conventional detonation are not only discernable, but detectable on other continents.
Oh, and an infrasound network recorded the shuttle breakup.
Strategically, there has been talk of the U.S. sharing sensor data with India, Pakistan, even Russia, to prevent accidental launches.
Aside from a bigger database of meteor recordings, researchers would like declassified infrared images from Air Force launch-warning satellites. These satellites have been seeing meteors for decades.
On-topic: missions to asteroids are the best way to determine their structural properties, and thus calibrate infrasound/IR databases.
to settle a long standing argument. When we are sure an asteroid is going to hit us we will attempt to stop it using only means that are not the result of weapons developement. That way we'll know for sure if all the hippies were right about war not doing anyone any good.
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Woops. Consider that the Saturn V could deliver just 49 tons to the Moon's orbit.
The Tunguska object, would have massed more than 500,000 tons -- maybe 5,000,000 tons. The asteroid Apollo, 1.6km in diameter, masses 20 billion tons -- 20,000,000,000 tons . How much power do we need to divert it?
The bottom stage of the Saturn V generates something like 160,000 horsepower, for something like 160 seconds. That is, if my arithmetic is right, something like 10^12 joules. Of course we couldn't get an intact Saturn V delivered to an approaching asteroid -- not with chemical rockets. The Saturn V could only deposit 50 tons to the Moon's orbit. But suppose we could? If the asteroid Apollo was going to impact right in the centre of Earth how far in advance would we have to light the candle of this theoretical Saturn V to divert the asteroid enough to miss us?
Kinetic energy == mass * velocity squared / 2
10^12 joules transmitted to 2*10^13 kilograms? If my Physics is not too rusty, will impart a velocity of one twentieth of a meter per second. Five centimetres a second? That is 0.18 km / hour.
At that rate you would have to light the candle on that theoretical Saturn V at least four years before impact to prevent the collision.
To be really safe, because tidal forces would rip the asteroid apart prior to impact. Tidal forces ripped Shoemaker-Levy 9 into fragments. So you would be better served lighting the candle decades in advance.
Now, consider how big a payload could we deliver to a comet or asteroid years or decades in advance? Miniscule.
So, what about using atomic charges? Asteroids might be as fragile as piles of rubble. A single charge might shatter the asteroid, leaving an uncontrollable cloud, still aimed at us like buckshot from a giant shotgun.
Would it matter if the asteroid shattered, if we didn't use one charge, but rather dozens, or hundreds, designed to explode more or less simultaneously? In the sixties there was lipservice paid to using atomic charges for peaceful demolition work here on Earth. The best known plan was to blast a 2nd, sea-level, Panama canal. One of the odd things you learned if you read about this was that if the charges all exploded at once you would get a trench with remarkably straight, even walls.
Or, consider how a shaped charge anti-tank warhead works. The charge is turned into a kind of lense of explosive. The business end has a conical hole carved in it. That cone is coated by a thin layer of copper. When the warhead explodes, the explosion travels through the explosive. When it gets to the apex of the conical hole it begins to focus the metal into a jet. I came across some really cool slow motion pictures of this process -- can't find them now though.
So, what if we landed a network of charges over one hemisphere of the asteroid, and had them go off in a rapid sequence? Could the expanding concussions redirect rubble away from the Earth, leaving a small amount of very rapidly moving small particles going east, and the rest of the asteroid going west, with essentially none coming right at us? If the asteroid shatters, would the overlapping concussions focus the bulk of the rubble in a single direction? Would charges spread all over the surface of one hemisphere help preserve the structural integrity of asteroid in a way a single charge wouldn't?
Ugh. If it's one thing I can't stand about slashdot is that all you people are CS majors or some such... Why I bother at all boggles the mind!
Okay, so here's the WHY of it. Asteroid composition is a very interesting subject because it seriously affects whatever technique you decide to use to divert a threatening asteroid. What you are looking for when studying asteroids is their porosity. Asteroids are not like they are portrayed on TV or in the movies, i.e. they are not solid chunks of rock. Instead, they can range from solid pieces of stainless steel (frigthening!) to loose aggregations of rubble (flying gravel piles) which are very porous. Porous materials are very good at absorbing energy and hence are much more difficult to deflect.
So, if one were to use a nuke on an asteroid that was porous, it would do a lot less to the porous asteroid than one that was solid through and through. So the purpose of these missions would be to scout out and start to get a better idea of what the distirbution (statistically speaking) of the porosity of the asteroids that are floating around out there. Their idea is to do this cheaply with ion propulsion. If you've got a lot of time to spend, ion propulsion is ideal to get around the inner solar system without spending a lot of mass on fuel.
If you have any more questions, I suggest you look at some papers by Ahrens or Holsapple. Also check out http://neo.jpl.nasa.gov.
-banjo
What's the point spending that much money on protecting the Earth, when George W. Bush has already dictated the way this planet is going to be destroyed.
It's about time that this matter is studied. But is it enough? No! There are many more asteroids that merit to be watched. And not only that, but we should put in place, at least talk about it, which should make our politicians happy, a system to defend ourself against such an event.
An open mind is as vast as the universe