XKCD comic on asteroids.

^ A Bad Idea. (You will now have a whole bunch of little asteroid pieces headed for you).

Still, has any government or space program issued an official statement on what it would do if a large object were found to be on a collision course with Earth?

  • 4
    $\begingroup$ The official plan is to argue about it, claim it does not exist, say that maybe it does exist but it won't really be that bad, blame it on a scientific conspiracy to get more grant money, and in the end do nothing until it is too late. $\endgroup$
    – Mark Adler
    Nov 10, 2013 at 17:09
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    $\begingroup$ Having a whole bunch of little asteroid pieces headed for you is better than having one big piece; the trick is making sure the fragments are small enough to burn up in the atmosphere. $\endgroup$
    – Hobbes
    Nov 12, 2013 at 19:54
  • $\begingroup$ Look for "Space Defence", "Space surveillance", "Space Situation Awareness", "Space Weather" and for Russian papers around, they're working hardly on this topic... I know there are at least three different organizations (USA, EU and Japan) estabilished to work on this topic, but I don't remember their names. $\endgroup$
    – jumpjack
    Apr 9, 2014 at 14:10
  • $\begingroup$ The question title asks about comets. But then you mention asteroids. In my answer I'm assuming you're interested in any potential impactor whether asteroid or comet. A long period comet with our name on it would be harder. Coming from the distant, darker regions of our solar system it'd be harder to see. If we sighted it 10 A.U. out, we'd only have a few years. In contrast, a near earth asteroid with our name on it could be discovered well in advance so we'd have a better chance to deal with it. $\endgroup$
    – HopDavid
    Apr 9, 2014 at 16:30
  • $\begingroup$ @HopDavid Yeah, I'm concerned about any big space rock that might cause us trouble. Thanks for your answer! $\endgroup$
    – Undo
    Apr 9, 2014 at 16:31

1 Answer 1


There's a little funding to search for hazardous asteroids. JPL has a growing data base of known near earth asteroids. We're doing a good job of finding the Chicxulub sized rocks. Rocks big enough for extinction level events are easy to see.

While we may have a good inventory of dino killers, potential city killers are another matter. Tunguska sized rocks are much harder to see. The vast majority of these rocks are probably still undiscovered. And the Tunguska or Chelyabinsk sized rocks are probably a million times more common than the Chicxulub sized rocks. To find these smaller rocks we may need orbital telescopes devoted to the search.

I hope to see the Asteroid Redirect Mission ARM funded. This mission calls for parking a small asteroid (5 to 7 meters) in lunar orbit. The proposed retrieval vehicle would be SEP (solar election propulsion) as described in the Keck Report. Such a vehicle would be too small to deflect a Chicxulub sized rock. But it might be able to deflect a city killer.

The co-authors of the Keck report include John S. Lewis, Chris Lewicki, Don Yeomans, as well as other well known scientists and engineers who study asteroids. Many of the co-authors are now part of Planetary Resources or Deep Space Industries, two companies that hope to mine asteroids for profit.

Deflecting larger asteroids would require space infrastructure. Our elected representatives are too ignorant and short sighted to fund it. But if mining space resources could return a profit, infrastructure would naturally grow. That is why I see Planetary Resources or Deep Space Industries as the best bets for planetary defense.

  • $\begingroup$ The OP was asking about comets not asteroids (which have been answered before here). Development of the Asteroid Redirect Mission was halted in Dec 11 2017 $\endgroup$ Jun 13, 2020 at 19:01
  • $\begingroup$ @astrosnapper, reread the OP. Asteroids are mentioned in the XKCD cartoon as well as the text. Reading comprehension -- get some. And I know ARM has been defunded. I wrote the answer to this question in 2014. $\endgroup$
    – HopDavid
    Jun 16, 2020 at 0:28
  • $\begingroup$ My bad, I hadn't realized this was from such a time in the past, it popped in the New Questions part of SX last week... weird... $\endgroup$ Jun 17, 2020 at 17:11

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