Relativistic Spaceship

Post by a_gnostic » Tue, Feb 06, 2024, 9:57 AM UTC

MilStdJunkie wrote: post #26

AlexAndScripts wrote: post #15

Earlier quoted context omitted.

I suppose you would also have to worry about surviving the trip - every atom in the interstellar medium would damage your ship, likely penetrating the entire way through, and electromagnetic repulsion would only work with charged particles.

Every proton would have the energy of a baseball. It's bananas. Granted, space is really empty, but it's not that empty, somewhere around a hundred atoms per cubic meter. Your ship might look like a very, very long shooting star. Probably dialing the speed down a touch would be worth it for whatever your shielding material is, but who knows? We're talking miracle engines here. I think in the "Valkyrie" ship-on-a-stri…

Post by _factor » Tue, Feb 06, 2024, 10:00 AM UTC

sudhirj wrote: post #288

abhibeckert wrote: post #152

Earlier quoted context omitted.

> Every proton would have the energy of a baseball I wonder if you could capture that energy and use it to generate thrust. Most of the energy is coming from your thrust so it'd be a lossy process however if you're able to capture all of the energy then there won't be anything left to damage the ship.

There's two different kinds of energy here - the kinetic energy of a moving thing hitting you in opposition is a problem. No way to capture that as far as I know - it's like running into a wall and asking how it can help you go faster. But then there's e=mc^2, so if the stuff you're running into is the fuel source for your fusion engine (could be a fission engine, but unlikely you'll run into heavy atoms like Uranium…

Post by _factor » Tue, Feb 06, 2024, 10:02 AM UTC

sveolon wrote: post #302

amelius wrote: post #184

Earlier quoted context omitted.

This is a bit like driving into a brick wall, and then asking if you could use the released energy to go faster ...

Imagine you drive into a wall of tnt, break through it, and as you exit it explodes and gives you an extra boost. Yes, you’ve lost some speed at the beginning but you’ve gained much more

Post by soco » Tue, Feb 06, 2024, 10:09 AM UTC

heads wrote: post #313

MilStdJunkie wrote: post #26

Earlier quoted context omitted.

Every proton would have the energy of a baseball. It's bananas. Granted, space is really empty, but it's not that empty, somewhere around a hundred atoms per cubic meter. Your ship might look like a very, very long shooting star. Probably dialing the speed down a touch would be worth it for whatever your shielding material is, but who knows? We're talking miracle engines here. I think in the "Valkyrie" ship-on-a-stri…

If you’re doing 2e8 m/s, your ship is long and thin with a 1m3 nose cone, and space has 100 baseballs per m3 then you’re being hit by 2e10 baseballs a second. How do I get an idea for what 20 billion baseballs (2TJ) feels like? Apparently bullets are about an order of magnitude more energetic than baseballs (800J vs 80J) so I guess I could try to build my intuition based on being shot ~2 billion times a second instea…

Post by lstodd » Tue, Feb 06, 2024, 10:13 AM UTC

heads wrote: post #318

kaashif wrote: post #315

Earlier quoted context omitted.

> A kiloton of TNT is 4GJ, so it’s also like a 500 kiloton bomb going off every second. Funnily, my first reaction to this comparison is that it makes it seem more plausible to me that this is possible. After all, a Star Destroyer can take gigaton level hits! But the problem with that is Star Destroyers are fictional. I've been spending too much time on spacebattles.com.

The numbers are big but they don’t seem “big big” like Sagittarius A* is big or the distance to Andromeda is big.