Re:James Webb Space Telescope Reveals That Most Galaxies Rot...
by jfengel on Monday March 31, 2025 @10:45PM
(#43542304)
Wouldn't it be biased towards nearby galaxies? A net rotation of the local cluster would be reasonable. But it would be very wrong to extrapolate that to the whole universe.
Re:James Webb Space Telescope Reveals That Most Galaxies Rot...
by EGreg on Tuesday April 01, 2025 @12:20AM
(#43542815)
Look, if the visible universe is expanding, as we think it is, that is already a direction. Viewing galaxies “from the other side” is not the same in an expanding bubble. It’s like being surprised that many things are redshifted no matter where you look. As for rotations — you could perhaps have some local coriolis force.
The visible universe is redshifted and galaxies are getting further and further away. So jumping straight to “we are in a black hole” is weird
It is far more plausible that there is some coriolis like spinning effect in a higher dimension, even if the universe is flat it could have similar effects to how the earth’s spin makes cyclones all spin in the same direction.
Problem solved. Next?
That said: I'd wait a bit here. This is a single-author paper by a non-astronomer (he's a CS professor). The sample size seems small (N=263), and the measurement coarse (he's just bucketing galaxies into "rotating in the same/different direction as the Milky Way"). And the technique may be too novel for its own good. The gold standard here would be to look at differential redshift, but all he's doing is applying a ML filter to detect the "twirl" direction in the image of the spiral galaxy. Which... might be amazingly effective or might fall on its face because of bugs in the filter.
But the signal seems strong, though (158 vs. 105 galaxies in each direction).
Basically, I'd wait a bit for someone to try to replicate with more data and more conventional measurements.