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Is our universe trapped inside a black hole? This JWS Telescope discovery

(www.space.com)
81 points janandonly | 2 comments | 15 Mar 25 13:03 UTC | HN request time: 0.405s | source
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fprog ◴[15 Mar 25 14:18 UTC] No.43372696[source]▶
An alternate hypothesis which seems equally interesting, albeit for different reasons, is at the end of the article:

> Another explanation for why the JWST may have seen an overrepresentation of galaxies rotating in one direction is that the Milky Way's own rotation could have caused it.

> Previously, scientists had considered the speed of our galaxy's rotation to be too slow to have a non-negligible impact on observations made by the JWST.

> “If that is indeed the case, we will need to re-calibrate our distance measurements for the deep universe," Shamir concluded. "The re-calibration of distance measurements can also explain several other unsolved questions in cosmology such as the differences in the expansion rates of the universe and the large galaxies that according to the existing distance measurements are expected to be older than the universe itself."

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perihelions ◴[15 Mar 25 14:44 UTC] No.43372859[source]▶
I'm utterly confused what's going on. They're measuring galaxies' rotations by looking at images of the subset that are spiral galaxies, and checking which direction the arms spiral. They describe their image processing algorithm in their paper [0]. (it's around figure 3)

How can local movement of stars within the Milky Way affect which way spiral galaxy arms are pointing?

[0] https://academic.oup.com/mnras/article/538/1/76/8019798.

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1. dvh ◴[15 Mar 25 18:32 UTC] No.43374338[source]▶
You cannot decide galaxy rotation by looking at it. Consider this gallaxy:

    _______   
    \   _ B\  
    /  /_\  \ 
    \  \_/   \
     \A____  /
           \/
Is A side closer to us, or is B side closer to us? You can't tell by just looking at it, if the B is closer that we are seeing bottom of the galaxy and it rotates CW. If A is closer than we are seing top of the gallaxy and it rotates CCW.
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2. AstralStorm ◴[16 Mar 25 01:57 UTC] No.43376441[source]▶
Yes you can, by gravitational lensing of another body. Works exactly by triangulation in Lorentz space. You can thank Einstein for this feature of special relativity.

(Tricky part is deciding it's another body from a picture. You would need a second JWST preferably far in the other Lagrange point. Stereoscopy solves it directly. You can )

The thing is, you need another galaxy in the way to be sure, or a black hole. Theoretically our Sun can serve. [] Or the supermassive black hole in the center of our galaxy, but the sensitivity might be a bit compromised.

And long observation time.

[] https://en.m.wikipedia.org/wiki/Solar_gravitational_lens It's a bit hard to put satellites in the right place.