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PhD Candidate Talks About the Physics of Space Battles
darthvader100 writes "Gizmodo has run an article with some predictions on what future space battles will be like. The author brings up several theories on propulsion (and orbits), weapons (explosives, kinetic and laser), and design. Sounds like the ideal shape for spaceships will be spherical, like the one in the Hitchhiker's Guide movie."
Do you mean Stephen Donaldson?
I'm reasonably familiar with Stephenson's work and do not recognize his 'Gap series'.
Nerd rage is the funniest rage.
Sounds like the premise of Heinlein's "The Moon Is a Harsh Mistress". Revolutionaries on the Moon take control of a mass driver and start flinging multi-ton barges at Earth, with just enough remote-control maneuvering that the shooters can call up Earth afterward and ask if they'd like to surrender.
Revive the Constitution.
Those gamma and X-rays are bad news when absorbed by stuff like a spacecraft hull. The photon flux is so high that even transparent substances like air absorb ghastly amounts of those. That's the source of the atmospheric shock from a nuke, and the source of the distinctive thermal double-flash: initial infrared pulse, occluded after a few nanoseconds by the atmosphere flashing into opaque plasma, and the resuming after the shockwave begins to dissipate the opacity. Any substance more opaque than air will just immediately flash to plasma and create its own shockwave in the rest of the target.
Yes, the inverse-square law applies to the photon burst from a nuke in space, so a nuke is not the large-area weapon it is in atmosphere. But to write off the huge pulse of ionizing radiation is mistaken. A contact or near-contact nuke would hurt bad.
A perfect x-ray laser would be immune to the inverse-square law, but a perfect laser doesn't exist. Every real-world laser will have a divergence angle; that would give the beam with an inverse-square behavior with a constant coefficient based on the ratio of the divergence angle as a solid angle and the solid angle of a unit sphere (4 pi).
Welcome to the Panopticon. Used to be a prison, now it's your home.
That is absolutely correct. The author seems to be unfamiliar with just how devastatingly destructive nuclear weapons are in space.
First, re. the airblast: the reason nuclear weapons have an airblast on earth is that the X-rays from the explosion are so intense that they superheat every piece of atmosphere (and ground, and ocean, and so forth) around the explosion, leading to rapid expansion. So if the detonation is near the ship, the ship itself will become just as superheated as the air that turns into the airblast on Earth. More, actually, because there's nothing to get in the way of the X-rays from the explosion.
Furthermore, the lethal range of the radiation from nuclear weapons in space is tremendously large -- many hundreds, if not thousands, of miles. While a kinetic kill vehicle has to actually hit you, a nuclear explosion doesn't have to be even close. And some of it may actually turn your kinetic shielding against you -- for example, bremsstrahlung.
Nobody pushes buttons like our bunny. Big red buttons with labels that say "IGNITION", apparently.