Recent content by DET

There's something about this thread that I find disturbing... :rolleyes:

Thank you!

1. Homework Statement I want to calculate the rotational period and surface velocity of a Bishop Ring with a radius of 80 km and a surface 'gravity' of 0.86 G I should note that this isn't for homework. It's for personal interest. I'm looking for a sanity check on this. The homework forum...

Ah, but he didn't have physicsforums, did he?

So a bunch of O'neill cylinders connected in a ladder configuration would have the same issue? Even if the connector was just cable? (even though that's unlikely to be the case)

Background: Larry Niven's Ringworld was declared to be unstable because it rotates fast enough to create artificial gravity on the inner surface (never mind the structural material issues) and is therefore not technically in orbit around the central star. So I've been reading up on the...

Tell him you'll be happy to answer his objections as soon as he proves to you that he exists.

Hmm, I don't see any way to support the number of habitable planets in any of those systems without descending into science fantasy. Oh well.

The Firefly universe (as I understand it) is a large number of planets orbiting a very large star with a wide habitable zone. Of course, to make that work, the star would also have to be reasonably stable and not emit lethal levels of radiation. Is there a stellar class that could, even in...

Looking at the earlier suggestion to put a superconducting ring around Mars -- would that not gradually heat the core through hysteresis, for instance? Granted, the time scale would be ridiculous. But maybe multiple lines of attack? Superconductiong ring providing inductive heating, plus H-bombs...

Has anyone ever come up with an even semi-plausible method of restarting Mars' magnetic field?

Woo hoo! I get to blow up the sun! :woot: Er, um, I mean, thanks very much for your help. Ahem.

Even punching straight through would be devastating, I think. I keep coming back to the slo-mo of the apple getting shot. Every bit of solar mass that gets shoved aside by the bullet would contribute to a shock wave, and probably create increased fusion along the way. In fact, I wonder if...

The problem I'm having here is that reductio ad absurdum says different. Let's take a planet with half the rest mass of the sun, and accelerate it until it has a tau of 20, so that effectively the sun gets rammed by a small object with 10 times its mass. Are you really asserting that this would...

Planet. Not sun, not black hole. A larger one moving at low speed, or a smaller one moving at high speed. "High speed" can include velocities above .99 C where relativistic mass is a factor. My question is: (1) What kind of result might such a collision create, where the requirement is that it...