What would happen if a very large commet or asteroid hit the moon? Are there any in the near future?

I just read Life As We Knew It by Susan Pfeffer. Very good book but it terrified me! I am wondering now if something like that were to happen, would these be the circumstances? Also is something like this supposed to happen in the near fututre? If you havent read the book it is a very easy read, eigth grad elevel.

6 Answers

  • 1 decade ago
    Favourite answer

    Nothing much.Only serious thing is that meteor sized pieces can hit earth but not in our lifetime

  • Yaybob
    Lv 7
    1 decade ago

    If a big enough object hit the moon, it would shatter it. The immediate effect would be to give earth a ring like Saturn. and to end tidal phenomena.

    The long term effect would be devastating to life on earth, and I think that this is what you're getting at. The moon stablizes the axial orientation of the earth. Without the moon, the axis of the earth, presently set at about 23%, would fluctuate widely and rapidly.

    The earth would periodically slip such that the north pole was pointed at or near the sun at times, and that would destroy many of earth's habitats and melt the polar ice and flood the shores.


    Here is an excerpt from an article at http://www.astrobio.net/news/article2507.html

    "The Moon’s tidal forcing causes significant heating and dissipation of energy to take place. Part of this energy is heating the Earth, and part of it is dissipated by forcing the Moon to recede from the Earth over time.

    "There are people who propose that the tidal effect of the Moon may have helped trigger the convection on the Earth that led to the multi-plate tectonics.

    "If you would take away the Moon suddenly, it would change the global altitude of the ocean. Right now there is a distortion which is elongated around the equator, so if we didn’t have this effect, suddenly a lot of water would be redistributed toward the polar regions.

    "The Moon has been a stabilizing factor for the axis of rotation of the Earth. If you look at Mars, for instance, that planet has wobbled quite dramatically on its axis over time due to the gravitational influence of all the other planets in the solar system. Because of this obliquity change, the ice that is now at the poles on Mars would sometimes drift to the equator. But the Earth’s moon has helped stabilize our planet so that its axis of rotation stays in the same direction. For this reason, we had much less climatic change than if the Earth had been alone. And this has changed the way life evolved on Earth, allowing for the emergence of more complex multi-cellular organisms compared to a planet where drastic climatic change would allow only small, robust organisms to survive."

  • 1 decade ago

    yep, depends on the size...

    most comets' nuclei are pretty small and would probably just result in a new crater on the moon's surface.

    there are some large asteroids which, if they hit the moon hard enough [meaning: fast enough] could probably destroy it. Ceres might be an example...

    on the other hand, most asteroids aren't that big and don't operate in orbits that bring them near the earth or the moon.

    however, as they orbit the sun, asteroids' orbits can be perturbed by the more massive planets or even gentle collisions with each other, and their orbits might be changed enough to bring them into the inner solar system and close to the earth and moon.

    current science shows that some very large objects have hit the earth and done some major damage. it's very likely that the results of the impact in mexico changed the earth's climate long enough to wipe out many plant and animal species, including virtually all of the dinosaurs. the evidence is pretty solid on that.

    if a big ENOUGH asteroid hit the moon, parts of the resulting debris might do the same to us, and at the very least, cause one amazingly intense meteor shower as the parts fell throught atmosphere and [hopefully] burned up before hitting the ground....

    scientists are currently running several sky-scanning programs to determine if any objects are likely to even get within a few diameters of earth.

    the good news is: space is VERY big and planets are relatively small in that vastness, so the odds of a big, bad hit to earth is slim. the moon, much smaller than the earth, is even less likely to be in the cross-hairs of a runaway asteroid.

    if we're lucky, humans might even develop some technology which could steer even the remotely dangerous objects onto paths that would preserve our safety. problem is: it takes one heck of a lot of energy to change an orbit like that, and a lot of energy to get the machine that'll do it close enough to the asteroid to give it a push!

    Source(s): Astronomy magazine recent issues have touched on this.
  • 1 decade ago

    the moon is a tough old bird... big, too.

    she can take a huge hit and survive. as was mentioned, fragments could enter earth orbit and eventually smack into us, but unlikely they would be big or do much damage.

    remember 'very large comet'... most comets are pretty small and low density. an iceball 10-20 km across wouldnt really be a test of old Luna. Just LOOK at her! she really has taken a beating!

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  • 1 decade ago

    Knowing my fellow man as much as I do, we would try to capture it and use it for a resource base in space, mining in space is not too far off in the future. I expect the moon base will be set up within 5 years. and that wil be a start of mankinds next great adventure.

    Source(s): the moon is a harsh mistress" Robert Heinlein among some of the works he has on space mining
  • Anonymous
    1 decade ago

    Depends on how big, but it might just split it into smaller chunks, and we'd have more than one moon. And it might screw up the tides and the weather.

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