Depends on the size of the fragments. If they are small enough, they should burn up before impact.

Bingo- simple, easy, and it works. Apparently half of NASA and the USAF haven't, or ignored Newtonian physics in high school. :P

I like the "should".

Oh, and where does the particulate debris go when it "burns up"? To Earth. Ok, you've made a rock the size of Denali into a swarm of pea stone. At best, someone is getting a silicon snowfall. :P

Yes, there was a pretty good science show on that went over the options pretty well, concluding that just trying to blow the thing up or off path probably wouldn't work, and would tend to make the situation worse. The general consensus is to try and steer the projectile out of collision path using a propulsion system that wasn't too abrupt so as not to create acute stress levels that might cause structural failure and fragment the object. That of course assumes we detect in with sufficient time to deploy such a system and the thrust applied long enough to clear the object out of path.

Nukes might disintegrate the smaller objects capable of surviving the atmosphere, but then you would have nuclear fallout raining down with the debris stream. The planet killer sized asteroids cannot be destroyed by nuclear munitions currently developed and capable of being deployed in such a manner. Regardless, we don't have anything that could deliver a nuke payload effectively as an interceptor, though the technology is there to build one if we wanted to. My guess is it will be another hundred or so years before we could begin deploying an effective global defense system that would fairly eliminate the possibility of a strike.

What's interesting is that only in the last 40 years have we had sufficient technological development to be able to even contemplate such a task. It is a race; to see whether we can develop quick enough to prevent our own demise, while also avoiding being the cause of it. At no other point in time has there been a species capable of changing their own fate so. It is amazing that we might actually pull it off in the span of one lifetime.

Sometimes I think we may actually learn how to live forever. Imagine how far science has come in the last 200 years, and how far it will advance in the next 1,000. Most Science fiction really only deals with future in the near term, but what about a millenium from now, assuming nothing disastrous were to happen in that span. If our technology were allowed to continue developing contiguously for that long, what limits that we know of today can be overcome? In time, I believe anything and everything is possible.

Completely agree with you on this. If identified early enough in the process, a small nudge when it's halfway across the solar system will deflect it away from the earth. Unless Bruce Willis and his rocket team isn't available to destroy it just before it hits the earth's atmosphere (I know, bad movie, but strangely entertaining. )

Honestly, if this event would happen in the next decade, I think we'd be better off making peace with the respective deity of our choice rather than planning to survive the impact. This type of event falls into my "Very Low Probability, Devastating effects, worldwide change, little that I can do about it" category.

Someone is working on planetary defense. And its not by using nukes. This article is a little dated, but I do see news items from time to time that indicate the group is still around and doing work.

http://www.voanews.com/english/archive/2...FTOKEN=61465346

According to a Discovery Channel program I saw 2+ years ago, as of 2001 the estimates were that we had only discovered a small percentage of the NEOs (near earth objects), and that current programs would take several decades to find and map them all. The upshot of that program was that without a lot more telescopes directed skyward searching for these things, we might only get a few days' warning - certainly not enough time to develop the technology to deflect or stop something.

The impact of Shoemaker-Levy on Jupiter proved it can and almost certainly will happen. The open question is when.


Frank2135

The general concensus seems to be that the President has the authority but that he would still need to turn to Congress for the funding. (I seem to recall a treaty that prohibits nukes in space. I doubt it would provide much of a constraint given the situation, but it might make testing problematic.) I don't believe for a minute a "black ops" account exists that is large enough to fund a project as huge as this.

The unsuitability of ballistic missiles to deliver the warheads is a good point. Am I wrong in assuming that NASA has and would use another type of rocket?

Some of the responses seem to suggest that trying to deflect an object with a nuclear weapon would be futile. But wouldn't that really depend on the size of the rock, the size and/or number of the nukes (after all, we've got thousands of 'em), the composition, and, maybe most importantly, the distance to intercept?

I think it makes sense to be prepared to do what we can do. It would be a shame if we were not ready to give a nuclear nudge to a 1/4 km wide comet that comes along because we got hung up trying to figure out the best way to shove a 5 km wide iron-core asteroid that isn't. By all means we should develop other methods but until then we should think about how best to use the tools we have.

And we definately need to get an early-warning system in place.

The big issue is not stopping the asteroid, its seeing in time to intercept it.
OK, a few facts:

1) TEOTWAWKI dinosaur killers (T-object) are not the main threat. They are easy to spot and deal with.
2) The real threat is nickle iron asteroids of 50 to 100m diameter. They are too small to see at any real distance and big enough to survive entry into the Earth's atmosphere. If one of them landed on a city it's goodbye London, Washington, New York etc.
3) The most powerful earth based radar has a maximum range of about 1 million miles (about 6 light seconds). It can only see asteroids of the size given above at about 1 1/2 light seconds.
1.5 L/sec is about the distance of the moon.

That means that you have less than a day at the sort of velocity's normally associated with interplanetary objects to spot it, calculate it's trajectory, launch and intercept it. You also have to "kill" it far enough away so as to prevent the E.M.P. pulse (Electromagnetic Pulse) for destroying ground based electronics. You also have the problem of fusing the Nuclear Demolition Device (sorry, sounds better than warhead)so as to ensure that the fireball reaches it's optimum diameter just as the asteroid reaches the same point. Too early and the fireball may be too diffuse. Too late and the asteriod may impact the N.D.D. before it can fuse. The differance may be as little (depending on the size of the yield)as a couple of milliseconds.

Also, contrary to received wisdom a T-object will cause far more harm intact than the same object would as fragments. If it has been shattered, a lot of it's mass will burn up on entry into the atmosphere. Despite Hollywood's love of drama, you would not launch only one device. You would launch as many as you possibly can. Sequence would be: Shoot, Look, Shoot. As needed. You also have the option of using the follow up shots to vapourise the remaining fragments.

We already have the means to deal with T-objects that are detected at interplanetary distances. All you need is accurate information with regards to it's trajectory and a fairly simple interceptor vehicle of the type used recently in NASA's asteriod impact mission. That would consist of a high impulse ion engine. As much fuel as possible and a depleted uranium rod, ball or bar on the front end. Idea is to hit the T-object at as high a velocity as possible. Mass x Velocity = Apparent Mass. In other words the faster it hit's, the harder it hits. Slows the T-object down by a few mm/sec. That is more than sufficent to generate a miss.

Agreed.



I'm not sure there is consensus on this.


Frank2135