Recent content by Halc

It seems that any angular velocity will do so long as it's high enough to involve centripetal acceleration of at least g. The problem needs perhaps another bit of information to narrow this down.

Not sure if the billion-years ago thing matters too much. The superclusters aren't going to change much in a billion years, and you only see stars when you're far closer than a billion LY away, so as long as your star map is good, you might make it. Nice software. My only criticism is that you...

Sounds like Niven's stasis field. It stops time inside the enclosed space, not turning off until it's safe. The occupants notice only a discontinuity, possibly billions of years later if conditions remain hostile long enough. Sounds like Niven's universe General Products #3 hull, immune to...

Yea, it does, but in dark mode, it should show as dark text on light background, or any other color that doesn't match the dark background. My eyes burn enough without websites trying to imitate a piece of paper under a 400 watt light.

Didn't read this whole thread, so maybe this is a dup. I frequently hit What's-new -> New-Posts and get a list of all topics that have action since the last time I did that. It used to precede each post with an avatar of the OP, but far more usefully, it would drop a teeny avatar of me in the...

I had posted the same. I was wrong. One can for instance bolt the output to a wall, preventing any rotation. The input can still turn freely. Hence the device acts as a disconnect between in and out. Only by applying friction at the yellow side knobs can torque actually make it to the output...

From what I can see, the input and output are always identical. It seems to be an interesting alternative to a through-shaft. There is no variability at all to the thing. A video showing otherwise would put me in my place. Both large gears turn at identical rates, slower than the smaller ones...

Ghost flower, discovered on a walk. This is a plant without chlorophyll. It is a parasite on fungus (another parasite) that grows on roots of the nearby trees.

This is wrong. He may compute this, but it is not what he sees. Both observers see the other clock run slow when they see the clocks receding. They both see it run fast when they see it approaching (by the same factors). This is mostly due to Doppler effect. Both observers see this. It is...

It measures a proper rotation rate, which is observer invariant. The axis orientation is also proper, effectively 'thataway', which again is observer invariant. Sure, coordinate orientation differs from one to the next, but the device outputs proper orientation, not numbers, similar to how a...

One of the more precise methods is to use a ring laser gyroscope, which leverages the Sagnac effect to determine rotation rate and axis orientation, all without looking out the window. Now where the axis actually is (not just its orientation) cannot be determined easily from our lab on Earth...

Indeed. It takes more coordinates to define a rotating frame (in say Minkowskian spacetime) that it does to define an inertial one. For one, the velocity of the axis (relative to what?) needs to be defined, which makes it relative to one specific inertial frame more than any of the others...

Good example of why proper acceleration is absolute. As for rotation, I suppose it is because the physics of a rotating frame is different than that of an inertial frame (relative to which linear motion is defined). So for example, in a rotating frame, objects at rest tend not to stay at...

Yea, but the tariffs bring it back up to 5

Maybe because the OP offered only a line and a snip from that link, and no actual commentary from yourself. The pawn thing was interesting, but had little direct relevance to the OP. It has been generally shown (not proven) that no such strategy can exist. Chess is a game of mistakes. If both...