Another Asteroid Close Call

james was one of a number of people that submitted the news that the earth has had another near miss, this time with an asteroid. This particular one is thought to be about 300 meters in length, meaning that if it had struck the earth, it would have destroyed an area of say...South Africa. Not to mention the fall out. But we don't need a better system for watching the stars. Nope. Obviously not.

Comments

Simple survival system

[richie2000]

DUCK!

Re:Simple survival system

[Sobrique]

The emergency procedure when being faced with being hit by an awfully large rock is to lower your pants bend down and kiss your arse goodbye.

A reason for funding?

[-douggy]

No ammount of near misses is going to make our political system fund observations into this when they are happy as pie spending billions on missile defence or giant tents if you are from the UK.

I am sorry to say it but, I beleive that a direct hit it what is needed to force our governments to take action. Hopefully it will be not too big and in an unpopulated area, but statistically we are bound to get wacked at somepoint.

Re:A reason for funding?

[brassman]

I am sorry to say it but, I beleive that a direct hit it what is needed to force our governments to take action.

But then they'll say "Oh, gee, something like that only happens once every 5,000 years, so we have lots of time before the next one now that it's finally happened."

I'd script it this way:
Bruce Willis: "On average? What does that mean?"
Jeff Goldblum: "It means we're about due for three of these."
Bruce Willis: "Oh."

This Just In

[Rope_a_Dope]

Taco Bell has announced that if an asteroid strikes a platform floating off the coast of South Africa, free chalupas to any living survivors.

More Information

[Goody]

Here's a list of PHAs (Potentially Hazardous Asteroids) and a simulation of the orbit of this particular asteriod.

Only thing a better monitoring system would do...

[maroberts]

..is tell us when we're all going to die.

We only get about a months notice of such close passes anyway and there is no way we're going to be able to get a 'Bruce Willis and mates' crew up into orbit in 30 days. A proper asteroid defence system is likely to be at least a decade away, as it is likely to require a number of hefty nukes to persuade an oncoming 300m+ asteroid that it doesn't have right of way.

Besides, I'd feel distinctly nervous about having a space based system loaded with a several very big nukes right above our heads; just imagine what could happen if a very small object hit the system and destroyed it, knocking the bits back into earths gravity......whilst I know you wouldn't get a nuclear explosion, what chances fallout in a similar manner to a "dirty" sub-nuclear weapon ?

Re:can anyone calculate the damage

[Sobrique]

Easy. E=mv^2 IIRC. So take the mass of something that size, multiply by the square of the impact velocity, and that's the 'energy' released by the impact.
It's not _quite_ the same as a nuclear explosion, but if you get the energy level high enough, then the effects are similar enough that it doesnt matter.
A kiloton is define as 10^12 calories which is about 4 x 10 ^ 12 joules.
A 1000 tons of rock would have to hit the earth at about 1 kilometer per second to have a similar effect - which is quite a small speed if you are talking about relative speeds in space... (escape velocity is 7km/sec IIRC)
Don't know what the mass of that rock would have been, but a 300 metre sphere of rock is going to be _fairly_ heavy. Take some averages, and count a few fingers, and you start realising that several megatonnes of energy are comparatively easy to come by if you're hit by a big chunk of rock travelling at significant speeds.
(This is, assuming I can count of course.)

Re:Only thing a better monitoring system would do.

[seanadams.com]

I always understood that nuking an asteroid was a little pointless. I mean, instead of one big chunk of rock coming towards you really fast, you instead have several.

Find a tile floor. Drop 500 marbles, all at once. Now try dropping a bowling ball.

Obviously, you're not a golfer. :)

But what to do?

[Chris Canfield]

The reason earth asteroid collision defense is not a huge priority is, as far as I can tell, there aren't any viable solutions. There are many positive monitoring projects in development stages, but no real solutions. According to that last project, we would have had to have intercepted our little 300 meter friend a full earth's orbit away with a 1 megaton warhead detonated on the surface to alter its course enough to not squish us. Considering how long before interception a missile would have to be launched, and the requisite amount of fuel, this is not practicle for, say, defense against a 1 km asteroid.

Nasa knows about 47 1km asteroids in near-earth orbits, any of which could make bickering about the RIAA rather short-lived. Their website claims that the best reason to study NEO's, as we don't have an active defense, is to "allow us to store food and supplies and to evacuate regions near ground zero." This is not the sort of confidence that inspires politicians to open their wallet, nor should it.

India and Pakistan are on the brink of bringing the world into a nuclear holocost. Our supplies of oil are depleting while our energy usage goes up. Ebola has broken out in another african village, and Aids rates worldwide are up to 1 in 100 with some areas reaching 1 in 3. Until such a time as there is something realistic we can do about near earth asteroids, that money is better focused on more pressing forms of armageddon.

�ber Bitchslap

[Knunov]

Any meteor, asteroid or comet that sets its cold, icy eyes on our beloved Earth needs to be pimpsmacked by one of these.

Russia's 100-Megaton nukes; the most powerful ever built.

One was detonated half-yield at Novaya Zemlya on October 30th 1961.

It was hypothesized that if one placed enough of these nukes in one spot, and detonated them simultaneously, one could knock the Earth of its axis.

It should make short work of a measely asteroid.

Knunov

Re:can anyone calculate the damage

[at_18]

Actually, the formula is E = (1/2)*mv^2

Now you have: a 300 m sphere rock at about 3 grams/cm3, which is about 42.000.000 tons. Speeds are in the 10-70 km/sec range, let's take 30km/s, or 30.000 m/s

The total energy is (1/2)* 4,2*10^12 (grams) * 30.000^2 (m/s)

or 1,2* 10^22 joules (!)

if a kiloton is 4*10^12 joules, we have that this asteroid impact has an energy of about 3*10^9 kilotons, or 3 MILLION MEGATONS, all of them released on a single point.

I hope that my calculations are not too way off...

Re:Only thing a better monitoring system would do.

[Phanatic1a]

Nice theory.

Problem is that all the kinetic energy still ends up in our system. One big piece is bad. Split that one big piece into several smaller pieces, and it's even worse. But take things to an arbitrary limit, where you pulverize the entire asteroid down to dust.

Now all that dust impacts the atmosphere, heats to incandescence, and vaporizes. Do *you* want to be in the hemisphere where *that* happens? Imagine New York City under the glare of 70 trillion E-Z-Bake Ovens.

If the asteroid's big enough to have a significant negative impact on human civilization, breaking it up/pulverizing it will not help us. It must be diverted so that it doesn't intersect Earth at all.

near miss is a relative term

[Eivind]

By all means, I agree that spending more money for space-research in general would be a good thing to do, including charting the orbits of anyything close to earth.

But it's sort of in the nature of these things that "near misses" will be very common compared to actual hits. Let's look at the numbers:

• The earth has a radius of about 6300 km.
• This gives a volume of about 10^12 km^3
• This asteroid was at the closest about 830000 km from earth
• A sphere with a radius of 830000 has a volume of about 2.5*10^18

If we divide these numbers, we find that an object will be this close to earth on the average something a bit more than 2 million times as often as it actually hits the earth.

So, if an asteroid this size hits earth on the average once every 500000 years, then we should expect that one comes this close to earth on the average 4 times a year.

Offcourse I'm simplifying a lot here, and offcourse this is statistics, we migth just as well be hit one month from now. All I'm saying is that it's not very surprising that something comes "this close" fairly often.