Can Apophis be Stopped?

Assuming Apophis enters the "keyhole" and is deemed a real threat, what can be done to stop it? It seems nuking it would be easiest, yet scientists repeatedly say that would be worse because the damage would be spread over a wider area. Intuitively, that has never made sense to me.

Consider, if you threw a one lb. rock at a sheet of glass, it would shatter. But if you threw one lb. of sand at it with the same force, it probably wouldn't because the energy is dispersed over a wider area. Now considering that Apophis is only 400 meters or so in diameter, it seems a nuke would vaporize a large portion of it, or at the very least reduce it to considerably less destructive bite-sized bits. I'd much rather take my chances with that scenario than having the motherlode going ka-thump. Thoughts?

yes, my first thought is whats apophis.

wikipedia(99942) Apophis (previously known by its provisional designation 2004 MN4) is a near-Earth asteroid that caused a brief period of concern in December 2004 because initial observations indicated a relatively large probability that it would strike the Earth in 2029. Additional observations provided improved predictions that eliminated the possibility of an impact on Earth or the Moon in 2029. However there remained a possibility that during the 2029 close encounter with Earth, Apophis would pass through a "gravitational keyhole", a precise region in space no more than about 400 meters across, that would set up a future impact on April 13, 2036. This possibility kept the asteroid at Level 1 on the Torino impact hazard scale until August 2006.

Additional observations of the trajectory of Apophis revealed the "keyhole" would likely be missed and on August 5, 2006, Apophis was lowered to a Level 0 on the Torino Scale. As of October 19, 2006 the impact probability for April 13, 2036 is estimated at 1 in 45,000. An additional impact date in 2037 has been identified, however the impact probability for that encounter is 1 in 12.3 million.

Despite the fact that there is no longer any significant probability of an Earth impact, the Planetary Society is offering a $50,000 prize for the best plan to put a tracking device on or near the asteroid.

if wiki is accurate then it is an 880 mega tonne impact compaired to the Tunguska event which was only 20 mega tonnes max, so basically, blowing it up would only cause a lot of huge impacts rather than one mega huge impact, so making evacuation more difficult than it clearly would be, but with only one impact and a few years it might be possible.

either way i'm glad it now looks unlikely.

[edit on 21-3-2007 by pieman]

Originally posted by yuefo
Consider, if you threw a one lb. rock at a sheet of glass.........

I think the deal here is that with one rock you'll possibly miss the target, but with bits of gravel or sand, something will more than likely hit.

Let's say Apophis was on a collision course. If it could be nudged when it's far from Earth, it would need less of a nudge to send it off course, so it could probably be done with less likelyhood of it splintering and bits heading in our direction. I think.

It´ll probably hit the moon first, thats what the moons for vacuuming solar missiles up. Should be an interesting sight.

Apart from that these things cannot be stopped, they are moving VERY fast for a start so any nuclear explosion would be like a fart in the wind.

i think one scientist said we can use gravity to move it. but the project needs to be started now so the technology is ready by the time it makes it's next pass.

They actually don't want to blow it up, because research indicates that this will just cause a rain of different sized pieces headed into the atmosphere. Instead, the current thinking is to divert its course, either by having an unmanned spacecraft fly next to it (tweaking it out of the way with gravity) or trying a "billiard shot" with a missle to push it away.

The safest way may be to just change the albedo of the NEO in question, or is it too late for that?

Deer slug vs. buck shot is a more appropriate analogy. Penetration isn't as great a concern as surface damage is, as most of us are on the surface.

Originally posted by apc
Deer slug vs. buck shot is a more appropriate analogy. Penetration isn't as great a concern as surface damage is, as most of us are on the surface.

That's a good point. But the most devastating effect expected from such an impact is the huge amount of super-heated material that will be ejected from the impact site. Smaller projectiles would put a few more holes in roofs, but they're not going to have the same atomic effect of the intact object. Keep in mind Apophis is only about 300 meters long. Blasted apart, the pieces aren't going to be very large.

And another thing, the effects on populated areas using the buckshot/deer slug analogy is negated if Apophis hits the ocean, which statistically is more likely. In that scenario Apophis intact would likely cause a world-wide tsunami. Would thousands of smaller pieces dispersed over a larger area even cause a tsunami? or if it did, wouldn't it have to be much smaller? I'm no good at math, but there must be an equation for this that addresses the ratio of energy reduction in relation to its dispersal over a wider area.

With that in mind, again I ask why scientists insist that blasting a comet or asteroid is worse that letting it hit in one piece? I'm unconvinced.

Perhaps the solution is to intercept with it and attach a solar sail to carry it to a higher orbit. Seems to me whatever you do could also involve an unforseen consequence.