An asteroid came within 70,000 miles of earth last week--the closest known approach in several years. That's just a few earth radii away.

It was big enough to destroy a major city. As Jay Manifold has pointed out, if it hit a major city on the Indian subcontinent (or anywhere in the region), it might have touched off a nuclear war, given the hair-trigger situation over there.

We really need to get more serious about these things.

I am sure that you have addressed this before, but other than increasing out abilities to spot one earlier, what are our options?

We really need to develop a true spacefaring capability, so that we can go out and rendezvous with them, and divert them far enough away that it's affordable to do so.

Follow up question. What are the requirements to move an asteroid of significant mass? Are we even close to having that kind of technology today? Could the space shuttle successfully rendezvous with an asteroid?

I apologize if you have already answered these question, just point me to the archive or article.

Thanks.

No, a Shuttle would not be practical for anything beyond low earth orbit. The answer to your questions depends on what you mean by "technology." Certainly we'd have to develop of lot of hardware that doesn't exist, but it's just an engineering problem. We certainly know more about how to do this now, than we knew about going to the Moon in 1960.

We did manage to land a probe on an asteroid last year, didn't we? Seems like we could put that experience to fruitful use.
Would it be a better idea to try to blow the things up, or just try to deflect their orbits?

Deflection is better. The technology needed to deflect is the same as that needed to mine the resources, and blowing them up may not have the desired effect. It could result in lots of smaller pieces hitting us in lots of places, rather than a single large one.

Heh, I was thinking about that (bad) movie "Armageddon"... the government figures out what to do, and sends a Space Shuttle out to blow up the asteroid. This sounds, from what Simberg says, to be unlikely.

Maybe the movie should have had Bruce Willis and his friends be a part of a non-governmental private enterprise that's trying to build spacecraft, and while the government idiots desperately try to fiddle with the space shuttle, Willis and his bros just get their stuff together, zip up into space like a new breed of cowboys, and deflect the asteroid. The government tearfully acknowledges their stupidity, and lets rugged individualism begin to conquer space. Roll credits!

I would think that (depending on size and velocity) it wouldn't take much to vector a rock away if we could rendezvous in time. Of course, I never was much at billiards... ;-)

Which implies that first we identify it in time. Have we become a race that sits and waits for it to hit? (whether terrorists or asteroids?)

Seems like a sad lack of imagination to me.

Science and science fiction has explored this a good deal. (You can bet it'll be a hot topic if Larry Niven comes to Solley's tonight as usual.)

Within the range you can exert any influence, starting the deflection far away is best in terms of the energy that must be applied.

Far away = minor course adjustment

Nearby = major course adjustment

Thus access to deep space vastly improves our chances of not just taking the hit. Step one is to get more virtual eyeballs out and about for detection. Step two is being able to intercept the object with something that can change its course.

This might come down to a stellar scale paintball attack. Coat one side of the object with highly reflective material to make it into an extremely clunky solar sail. It only has change its course a wee little bit.

It seems to me that the first thing to do is FIND the asteroids that could be a threat to us (say, 50 meters or larger), whether they are presently nearby or in the outer solar system. While I'm happy that NASA missions like Kepler, which will detect earth-sized planets around other stars, are going through, I can't help but think that we should be using that same technology to spot asteroids within our own solar system. This should be done either before or concurrently with the Kepler mission, and could probably be done on the cheap as much of the technology and hardware needed would be similar if not identical for both missions.

As an engineer in training, I am not entirely certain if this approach is valid. From the standpoint of technology requirements, does anyone know if asteroid hunting is similar to looking for other earths?

No, it's a different problem. Looking for extrasolar planets is an indirect process (or at least it was until recently), involving looking for wobbly stars, where the wobble is caused by the gravity of an unseen planet.

Asteroids aren't big enough, as a rule, to noticeably perturb other bodies--they have to be sought directly. But with prices coming down on computer-driven amateur scopes, and digitized images that can be analyzed by PCs, this could become a massively-parallel search, by setting up a central site to coordinate the search, similar to SETI@home.

We need to get the Australian and South African and South American public interested in this--their politicians, at least Down Under, are too dim to understand the importance.

Thanks for the reply. I heard something about astronomers in Australia requesting funding for asteroid hunting (maybe Spaceguard?) and being laughed at by the politicians in charge. Here's hoping that the first asteroid to hit us this century comes down somewhere unihabited.