Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

What future space combat would really look like

forums.spacebattles.com

Post reply on HN
Print view View original

231–235 of 235 posts

Re: What future space combat would really look like

#231

Post by pdaviesa »

brazzy wrote: post #145
sliverstorm wrote: post #129

Earlier quoted context omitted.

You can argue this over in your head a lot, but it's really quite simple in my mind. If we assume space travel becomes relatively easy (that is to say it is used for more than initial colonization) there will be interstellar commerce. If there is unprotected commerce, there will be pirates. Any time there are pirates, protection will develop. Let us call these peace-keepers the Navy. If you engage in commerce and you…

Read TFA, it argues pretty convincingly that there will not be pirates because A) you can't hide in space and B) Any ship is a WMD, so governments will do anything to keep them out of the hands of criminals, and protection rackets would be a far more profitable use for them than raiding commerce.

The minute someone says "that's impossible, there is absolutely no way that will happen", someone else begins to devise a way to make the "impossible" scenario/product/achievement possible. Incedentally, the typical HN reader falls into the latter category - so carry on space pirates!

Re: What future space combat would really look like

#232

Post by Nick_C »

dalke wrote: post #147
cschneid wrote: post #69

Earlier quoted context omitted.

Asteroids don't pump out waste heat. Things get a lot more obvious when heat differentials are big.

I was commenting on Talmand's scenario; take "three of the world's largest ships, put them together to form one ship and then placed it in a random spot somewhere within the orbit of Pluto; how long would it take you to find it?" Using the formula in the "Refrigeration" section of the page linked to by Avshalom, the "maximum range a ship running silent with engines shut down" (assuming diameter = 500 m and temperatur…

You are using averages where the min and max are extremely wide apart. For example, the Moon is not actually at -25C, it is either +130C or -110C (or transiting between). We know the time when those temps occur, so we can look for other objects not at those temps at that time. Same goes for the other objects.

Re: What future space combat would really look like

#233

Post by dalke »

Nick_C wrote: post #232
dalke wrote: post #147

Earlier quoted context omitted.

I was commenting on Talmand's scenario; take "three of the world's largest ships, put them together to form one ship and then placed it in a random spot somewhere within the orbit of Pluto; how long would it take you to find it?" Using the formula in the "Refrigeration" section of the page linked to by Avshalom, the "maximum range a ship running silent with engines shut down" (assuming diameter = 500 m and temperatur…

You are using averages where the min and max are extremely wide apart. For example, the Moon is not actually at -25C, it is either +130C or -110C (or transiting between). We know the time when those temps occur, so we can look for other objects not at those temps at that time. Same goes for the other objects.

I am definitely using averages because if you have an ship which is 300+ meters across then you can leave the top few meters for insulation, so the surface of your ship has the expected extreme temperature ranges.

I should restate what I said: instead of "that's assuming the entire asteroid is at 290K", I mean, "except the insulation layer", which you need anyway to keep the near-surface area livable.

If you need 20 meters for that, then your living volume is 21 million cubic meters, or a reduction of about 20%.

That's not to say that there's no contribution. More that I believe the calculations from that linked-to page ignore the difficulties of differentiating between the internal heat (cooled through black-body radiation) from surface heat from the sun.

For example, from Stefan-Boltman, cooling goes as T * * 4, which means if you have a cooling radiator on the sun-side which is at 150C, or 20C above "normal", then it's about 6 times more effective than a -90C radiator on the cold side. I suspect it's easier to stop the 20C delta on the cold side than the warm side.

Re: What future space combat would really look like

#234

Post by dalke »

scarmig wrote: post #122
Locke1689 wrote: post #108

Earlier quoted context omitted.

If you can create wormholes at will, you don't need bombs. Put one end of the wormhole in the target and the other in the center of the sun.

Any guesstimates on how large the wormhole would need to be for it to be a doomsday device? Two estimates, one for a wormhole on the surface of our sun, and the other for its core. I'll try to post my results sometime later. What about a neutron star? It's probably too exotic to consider how a wormhole would interact with a black hole.

That makes little sense. Do I assume that use of a wormhole circumvents thermodynamics? After all, the sun is in the bottom of a rather large gravity well. It's about 900 MJ/kg from the sun to earth (I think that's measured from the core). A megaton explosion is 4.184 petajoules, so if you could move 5,000 kg from the sun to the earth then it's the same amount of energy you would need to set off a megaton explosion.

I don't know how much density is in a 5,000 kg chunk of the sun.

Re: What future space combat would really look like

#235

Post by schiffern »

lloeki wrote: post #227
schiffern wrote: post #158

Earlier quoted context omitted.

You should read The Killing Star: https://en.wikipedia.org/wiki/The_Killing_Star Spoiler Alert! In the late 21st century, Earth is at peace, sending fleets of Valerie spacecraft to the stars. Without warning, relativistic kill vehicle obliterate the surface of every planet, and a mop-up fleet of ships begins hunting down the humans that remain. The last two humans on Earth are kept as zoo specimens. They ask why thei…

Classic case of MAD. "The only winning move is not to play" .

The problem is that any development of interstellar vessels constitutes "playing".
Post reply on HN