Pun intended, but still a serious question.

Would a neutron matter? (Pun also intended, but also serious)

  • TomMasz
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    221 day ago

    This is why Star Trek’s Enterprise has that forward-facing deflector dish. It wouldn’t last very long without something to prevent such collisions.

    • @Xaphanos
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      181 day ago

      By my back-of-the -envelope math it is 4,500,000,000 joules. The Hiroshima bomb is listed at approximately 10,000,000,000,000 joules. I bet xkcd is far more accurate, though.

      • @[email protected]
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        201 day ago

        How did you calculate that? The question didn’t even mention a specific speed, just “near the speed of light”.

        The kinetic energy for a grain of sand near the speed of light is somewhere between “quite a lot” and “literally infinity” (which is, in a sense, the reason you can’t actually reach light speed without a way to supply infinite energy).

        • @Xaphanos
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          181 day ago

          Ke=1/2 M V^2 Not relativistic. So wildly low. But certainly a low bound. My point being that nuclear bomb grade energy is certainly in the ballpark.

      • @Death_Equity
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        71 day ago

        Did you assume the sand as having no velocity relative to the object going C?

  • @cynar
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    231 day ago

    It’s actually a legit concern with any (hypothetical) interstellar mission. Even hydrogen atoms will hit with significant force. Dust hits like nukes, and an asteroid is just game over.

    The maxim used in a lot of sci-fi is an ablative armour plate. Often in the form of ice. Interstellar ships would likely aldo be needle like, to minimise their cross section. We could also use electric and/or magnetic fields to move smaller particles out of the way.

    As for densities, I believe it’s a couple of hydrogen ions per m^3 . Dust is rarer, but still present. It’s only bigger rocks that are rare enough to just hope to avoid.

    • @slickgoat
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      523 hours ago

      Didn’t one of the space shuttles almost holed by a fleck of paint?

      • @cynar
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        821 hours ago

        The ISS has been pinholed by debris a few times. Likely paint. The shuttle was damaged by foam breaking off, amongst other events.

        By comparison orbital velocity is around 7km/s, while a bullet is around 0.367km/s. Any mismatch will push debris up to bullet speeds easily.

        As for relativistic speeds. C is 300,000km/s assuming you get up to 1/3C (barely relativistic) you are moving at 100,000km/s or 14,000x faster than the ISS moves, or 39000x faster than a bullet. A 10g rock would hit with 10kilotons of energy. About 2/3 the energy of the first atom. bombs.