Close call!

[Jobar]

I subscribe to Spaceweather.com, and this morning I got this message:
There's no danger of a collision, but newly-discovered asteroid 2009 DD45 will come close enough today when it flies by our planet 72,000 km (0.00048 AU) away. That's only twice the height of a geostationary communications satellite. The asteroid measures 30 to 40 meters across, similar in size to the Tunguska impactor of 1908. Closest approach occurs at approximately 1340 UT (5:40 am PST) on March 2nd.

I've always heard that a miss is as good as a mile, but when you're talking impact energies in the megaton range, I'd be much more comfortable with a LOT more than a mile- more than 50,000 miles, in fact.

I know this is an old topic, but what do you think we could do if we found that an asteroid like this- not a Dinosaur Killer, but the sort of thing that could level a city if it hit in exactly the wrong place- was going to strike the Earth, in, say, three years? Could we get to it and change its orbit- undoubtedly with a nuclear device- in time? Would we be able to get our shit together, spend the hundreds of millions or billions of dollars needed, and prevent an impact of this sort?

[BWE]

I think people could get it together to give it a try.

[Ray Moscow]

We'd have a hard time stopping it, even if we knew about it. The latter is the bigger problem.

[Christina]

Is the scenario that they always use in cheesy megadisaster movies at all potentially realistic? They all shoot nuclear weapons into it to try to push it off it's path or break it into smaller pieces that end up hitting us anyway.

[Jobar]

I read somewhere that right now we have maybe a 50/50 chance of spotting a rock big enough to penetrate the atmosphere, on an intercepting orbit, at least a year before it strikes. And that figure is constantly improving as we put up satellites and improve detection technology.

I think that if we spotted something like that, it would depend largely on *where* it was predicted to strike. If it was anywhere in North America or Europe, there would be a huge effort expended to shift it. But if it was going to hit somewhere in equatorial Africa... well, color me cynical, but unless it was big enough to cause worldwide effects, I expect that it would hit. Oh, I suppose there'd be a large effort to move people out of the expected impact area, but maybe not even that, depending on the political situation there.

[Jobar]

For an asteroid below a certain size, breaking it up and scattering it widely would be an adequate solution; even if the fragments hit they'd burn up in the atmosphere.

For a really big one- a Dinosaur Killer- we'd want to try to leave it in one body, and plant nuclear weapons on the surface so that they'd act as rockets to push the whole thing out of its intercepting orbit. Given enough lead time- ten years or more- that wouldn't be all that terribly hard (unless it was truly huge- five miles or more across.) All we'd have to do is give it a few pushes in the proper place and time, and let gravity slingshot it away from the Earth.

It's the close ones- in space and in time- that are the most difficult to move, even if we had dedicated systems designed for it.

[Brother Daniel]

In the unlikely scenario where we successfully divert a disaster-by-asteroid, we'd be inundated with conspiracy theories about what our governments were "really" up to. "They put nukes in space! There must have been a far more nefarious reason!"

[Uthgar the Brazen]

Why on earth would we want to do that? I've been beseeching assorted angels, demons and gods for years to let one finally clobber us!

[Jobar]

Why on earth would we want to do that? I've been beseeching assorted angels, demons and gods for years to let one finally clobber us!

Well, if ever it appears that one is going to strike somewhere in Antartica, or maybe in the Sahara, I'll be sure to let you know, and will even contribute towards your transportation expenses so that you can go there to greet the meteoroid people. Hey, I'll even try to get some major network to hire you as a cameraman.

At least temporarily. :D

[Uthgar the Brazen]

Meh. Species-culler or bust! By which I mean more than just me!