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Space Science

Earth Under Threat From Dark Comets 149

An anonymous reader writes "Comets could be the most significant impact hazard to Earth, with sky surveys underestimating the number that are potentially devastating by a factor of between 10 and 100, UK astrophysicists say."
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Earth Under Threat From Dark Comets

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  • Re:Seriously? WTF? (Score:4, Interesting)

    by XxtraLarGe ( 551297 ) on Monday February 16, 2009 @12:13PM (#26873133) Journal

    Though any given comet won't pass near the Earth anywhere near so often, they exist in colossal numbers, and for all we know one could come barrelling out of the dark to kill us all next month.

    Sounds like there's not really any reason to worry about it then if there's nothing we can do. Isn't that the definition of FUD?

  • Extrasolar objects (Score:2, Interesting)

    by symbolset ( 646467 ) on Monday February 16, 2009 @03:24PM (#26875751) Journal

    Somebody else covered asteroids, so I'll touch on another risk: extrasolar objects. You see, a lot of discussion is made of object in our solar system because they are things we have to study for long periods of time; we can see them. However our solar system is orbiting the center of our galaxy in concert with a vast quantity of other material. Things can and do achieve escape velocity from our solar sytem, like the Voyager probes.

    Not all the mass in our galaxy belongs to a star. Some of it - the remnants of supernovae, agglomerations of interstellar dust, stray comets ripped away but not captured by close passing stars - wanders the dark realm between the stars. This stuff is hard frozen and the vast majority of it is fine dust. Unfortunately not all of it is. The Earth is struck by extrasolar meteors every day, and some of them have good size. Because of their different origin they can be moving much faster relative to the Earth than an object that's been circling our common star for billions of years.

    It would be unfortunate if we were struck by one of these objects that is a mile or more in diameter.

"I'm not afraid of dying, I just don't want to be there when it happens." -- Woody Allen