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Question: The article mentions that a 1kg projectile travelling at 99% of the speed of light would have such and such more explosive energy than the most powerf

by dougk16 12y ago

Question: The article mentions that a 1kg projectile travelling at 99% of the speed of light would have such and such more explosive energy than the most powerful nuclear bob ever detonated. I don't doubt the math, but would the destructive effects (e.g. to a city) of such a projectile weapon actually equal those of a nuclear bomb? I'm not talking about the radiation and such in the aftermath, just the explosion itself. Wouldn't the projectile basically go straight through a planet? Edit: I suppose the shockwave from entering the atmosphere would cause a bit of a rucus too...still interested in any responses.

blackstache 12y ago
This might give the beginnings of an idea of what would happen: https://what-if.xkcd.com/1/ https://what-if.xkcd.com/1/
- dougk16 12y ago
  Interesting, thanks for the link. Intuitively it still seems like much of the energy from the projectile would be absorbed deep in the Earth as it traveled through. For sure it would cause some damage, but it still seems like a nuclear bomb would have a higher effective energy, as far as the tactical goal of taking out a city or something.
  - TheLoneWolfling 12y ago
    You can adjust effective penetration depth by the "density" (read, mass per unit cross-sectional area) of the projectile. You could go anywhere from an osmium needle through to a Mylar disk. Another relevant XKCD: https://what-if.xkcd.com/20/ https://what-if.xkcd.com/20/
mikeash 12y ago
From the perspective of the RKV, the Earth will look like a cloud of fast-moving subatomic particles irradiating it with a power that substantially outshines the sun. The particles that make up the RKV will collide with and impart their energy to bits of the Earth (or its atmosphere) in pretty short order. Those will impart their energy to other bits of the Earth, and so forth, forming a normal (aside from scale) shockwave made up of bits of Earth (or its atmosphere) and bits of the vaporized RKV.

by dougk16 12y ago

blackstache 12y ago

This might give the beginnings of an idea of what would happen: https://what-if.xkcd.com/1/ https://what-if.xkcd.com/1/

dougk16 12y ago
Interesting, thanks for the link. Intuitively it still seems like much of the energy from the projectile would be absorbed deep in the Earth as it traveled through. For sure it would cause some damage, but it still seems like a nuclear bomb would have a higher effective energy, as far as the tactical goal of taking out a city or something.
- TheLoneWolfling 12y ago
  You can adjust effective penetration depth by the "density" (read, mass per unit cross-sectional area) of the projectile. You could go anywhere from an osmium needle through to a Mylar disk. Another relevant XKCD: https://what-if.xkcd.com/20/ https://what-if.xkcd.com/20/

mikeash 12y ago

From the perspective of the RKV, the Earth will look like a cloud of fast-moving subatomic particles irradiating it with a power that substantially outshines the sun. The particles that make up the RKV will collide with and impart their energy to bits of the Earth (or its atmosphere) in pretty short order. Those will impart their energy to other bits of the Earth, and so forth, forming a normal (aside from scale) shockwave made up of bits of Earth (or its atmosphere) and bits of the vaporized RKV.