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James Webb Space Telescope reveals that most galaxies rotate clockwise

smithsonianmag.com

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Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#41

Post by soulofmischief »

MichaelZuo wrote: post #32
andrewaylett wrote: post #22

Earlier quoted context omitted.

Clockwise relative to our viewpoint, while we would expect that we'd see an equal number rotating in either direction no matter which way we looked or where we were looking from.

How does that follow? I imagine there was already a preferred spin of gases immediately after the big bang, just due to random chance, so why wouldn’t that be preserved more or less?

It's still of great interest to understand why exactly symmetry broke, and how this news might affect the cosmological principle.

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#42

Post by worldsayshi »

andrewaylett wrote: post #22
worldsayshi wrote: post #15

Clockwise relative to what? Does the universe have an "upwards" direction? Or is it just relative to all the other galaxies?

Clockwise relative to our viewpoint, while we would expect that we'd see an equal number rotating in either direction no matter which way we looked or where we were looking from.

> relative to our viewpoint

That would seem way more surprising than relative to a arbitrarily selected common upwards direction and it would imply that we are somehow at the center/top of the universe.

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#43

Post by RotationPedant »

snitty wrote: post #6

If we were on the other side of those galaxies, wouldn't they look like they were spinning counter-clockwise? Or are they measuring spin some other way?

That is correct, "clockwise" only makes sense relative to a single observer: on Earth we set up out coordinate system so that the Milky Way's directed axis of rotation points one way, and most galaxies have it pointing the other way. "Clockwise / counterclockwise" makes sense for images coming from telescopes but it's not cosmologically meaningful.

Note that this is not that easy to determine:

  When done manually, the determination of the direction of rotation of a galaxy can be a subjective task, as different annotators might have different opinions regarding the direction towards a galaxy rotates. A simple example is the crowdsourcing annotation through Galaxy Zoo 1 (Land et al. 2008), where in the vast majority of the galaxies different annotators provided conflicting annotations. Therefore, the annotations shown in Fig. 1 were made by a computer analysis that followed a defined symmetric model (Shamir 2024e).
The point is that we would typically assume a 50-50 ratio regardless of where you are in the universe.

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#44

Post by albertzeyer »

over_bridge wrote: post #35

Seems like we've got a few of these imbalances now where you'd expect 50:50 but instead it's skewed to one side where nature had a different idea Matter-antimatter ratio Left vs right handed molecules Now galaxy spin directions Maybe there are others I missed too

For the matter-antimatter ratio, you would not expect 50:50, or would you? Because 50:50 would be a highly unstable system? In any case, you would expect that unstable states would be highly unlikely, and it would converge into a stable state.

I'm not sure about the other examples. But maybe it's a similar reason that it is not a 50:50 ratio?

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#45

Post by pandemic_region »

d--b wrote: post #4

> This preferred direction of spin might be due to one of two reasons: either our entire universe exists in a black hole, or astronomers have been measuring the universe’s expansion incorrectly This is the subtitle of the article. It’s such a great summary!

Of all the mind-boggling answers explaining this direction-of-spin thing, they picked the one saying "Hey actually you know what, our entire (mind-boggingly large) universe itself is located in a black hole. That'll explain things nicely."

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#46

Post by otikik »

over_bridge wrote: post #35

Seems like we've got a few of these imbalances now where you'd expect 50:50 but instead it's skewed to one side where nature had a different idea Matter-antimatter ratio Left vs right handed molecules Now galaxy spin directions Maybe there are others I missed too

The fact that we have found left-handed neutrinos but not right-handed ones seems like another one.

https://en.wikipedia.org/wiki/Sterile_neutrino

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#47

Post by [deleted] »

over_bridge wrote: post #35

Seems like we've got a few of these imbalances now where you'd expect 50:50 but instead it's skewed to one side where nature had a different idea Matter-antimatter ratio Left vs right handed molecules Now galaxy spin directions Maybe there are others I missed too

[deleted]

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#48

Post by z33k »

perihelions wrote: post #34
scythe wrote: post #30

Earlier quoted context omitted.

>Due to an effect called the Doppler shift, astronomers expect galaxies rotating opposite to the Milky Way’s motion to appear brighter, which could explain their overrepresentation in telescopic surveys. I found this a little surprising as well

- "Doppler shift, astronomers expect galaxies rotating opposite to the Milky Way’s motion to appear brighter" But how does that work?

I'm not an astronomer, but my intuition is this: When the source of the light is moving towards the observer, each successive photon emission happens from a position closer to the observer than the previous photon. Hence, from the observer's perspective, the time between photons is reduced, meaning more photons are observed in a given time, and the brightness is increased. When we observe a galaxy that is rotating opposite to us, not only is the source of the light moving closer to us, but we are also moving closer to it.

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#49

Post by hhjinks »

albertzeyer wrote: post #44
over_bridge wrote: post #35

Seems like we've got a few of these imbalances now where you'd expect 50:50 but instead it's skewed to one side where nature had a different idea Matter-antimatter ratio Left vs right handed molecules Now galaxy spin directions Maybe there are others I missed too

For the matter-antimatter ratio, you would not expect 50:50, or would you? Because 50:50 would be a highly unstable system? In any case, you would expect that unstable states would be highly unlikely, and it would converge into a stable state. I'm not sure about the other examples. But maybe it's a similar reason that it is not a 50:50 ratio?

A 50/50 matter/anti-matter system could still house stable local pockets of mostly matter or anti-matter. The problem is, from what I understand, that the universe seems to have sprung into existence with way more matter than anti-matter, and we don't know why.
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