Is our universe trapped inside a black hole? This JWS Telescope discovery
space.com
space.com
> 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."
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.
The author writes about the Doppler effect creating a systemic bias in brightness depending on which way the galaxies are rotating. I don't understand that argument either, but it's moot, because they state categorically that that effect would be too small to explain their results. ("This explanation is challenged by the fact that the effect of the rotational velocity have merely a mild impact on the brightness of galaxies, and therefore is not expected to lead to the dramatic difference of 50 per cent in the number of galaxies as observed through JADES.")
That's the only explanation I recognized as an explanation. Then I lost track of their argument following that. They refer to several speculative physics theories like MOND, but I don't understand them to be saying something that concretely predicts distant galaxies to appear to be rotating differently.
I'm appealing to anyone on HN who knows enough about this field to understand the meat of this argument.
This one of the author's other papers they cited in this one,
https://www.mdpi.com/2073-8994/15/6/1190
I'm completely lost how they're eliding between the rotation orientation of the Milky Way galaxy, and relative linear velocities with stars in other galaxies. In the special relativity argument, where does the rotation axis of the Milky Way enter?
So I’d suspect they’re saying time and distance would need to be factored in rather than just looking at static images relative to our position today since our own spin may have caused a particular galaxy to appear to have been spinning in a different direction at another point in space-time
I don't see how time-intermittent frame captures from our own position affect that interpretation. Or are we using an astonomy-specific definition of spin here?
If you are standing on the side of a road, and a bicycle goes by, then you may observe the wheels to rotate clockwise, while an observer on the other side of the road will observe the same wheels to rotate counter-clockwise.
The sun is said to rotate around the centre of the milky way galaxy once every 225 million years. Over that time frame, some of the galaxies we observe will flip between clockwise and counterclockwise rotation as our viewpoint changes.
But that isn't relevant here. The Space article is too vague and handwavy to make any conclusions about the research, and should be ignored. Only the original scientific paper is worth reading: https://academic.oup.com/mnras/article/538/1/76/8019798?logi...
Section 5.2 "Physics of Galaxy Rotation" seems particularly relevant.
> due to the Doppler shift effect galaxies that rotate in the opposite direction relative to the Milky Way are expected to be slightly brighter than galaxies that rotate in the same direction relative to the Milky Way. Therefore, more galaxies that rotate in the opposite direction relative to the Milky Way are expected to be observed from Earth, and the difference should peak at around the Galactic pole. That observation is conceptually aligned with the empirical data of Fig. 10, and the observation using JADES described in Section 3.
You should read the paper for the full argument.
Not entirely. The galaxy is bound by gravity and the stars rotate in the galaxy around its baricenter. We can compute how fast it must be rotating from the amount of visible matter. Enter dark matter and various complications, but still, you can tell that it's rotating and which way.
And for galaxies we see edge on we can use the difference if redshift on one end versus the other to tell which way it is turning.
_______
\ _ B\
/ /_\ \
\ \_/ \
\A____ /
\/
(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.
ELI5: Per "5.2 Physics of Galaxy Rotation", could the Milky Way's relative movement, in addition to its spin, also effect the observed assymetry? In Figure 10, is the Milky Way also moving toward the blue and away from the red?
Thanks for humouring my question. Everything about astronomy and JWST just blows my mind. Like how Figure 10 sorta resembles yinyang. What a time to be alive.
Also meaning that “our” blackhole (the one containing us) is unobservable from the parent universe for the same reason. So where is all this extra light/energy going in our universe? Should we not have detected an increase of energy in our universe?
Perhaps that's dark energy or vacuum energy? If mass and time truly switches places when crossing into a black hole, it would make sense that the spacetime size of this universe translates into observable mass outside it. Which might tie it to the expansion of the universe.
What do you mean by that?
By one or two seconds in the parent universe’s time scale, our universe will have settled down to its extremely long state of being a cold, dark void of slowly decomposing subatomic particles.
No good reason to think this, just feels right.
I recall reading about our universe as a black hole once -- one thing posited is that everything that is happening and what we think of as space is really information processing occurring just at the surface of the event horizon. There was some possible way of explaining non-local phenomena like entanglement that way, but I forget the details.
It's fascinating to think about how the actual universe might be something quite alien from our ordinary perception. It's not that our ordinary perception is wrong. What we're perceiving is just one perspective on something much larger and weirder. In this case our perspective would be from within this information substrate. It's almost universe-as-simulation, except that the simulation does not have a builder. It's a naturally occurring phenomenon. The Matrix has no architect, or if it does it's something fully outside the event horizon of this object and thus un-observable.
Of course at this point we're well into physicists smoking pot territory.
sadly, this is likely the real explanation, but that's not very exciting
Would matter falling into our black hole come shooting out of the white-hole we see?
Would time on either side of the event horizon even be related?
Something to consider is a possible time scale difference. Eg time could be dilated for us for being around so much density.
I think that's exactly the right question to ask. And ask it for space too. Perhaps the entire history of the interior universe unfolds between the black hole's formation and its final evaporation. Perhaps a heat death of the interior universe, where everything spreads out until nothing interesting is left, can fit inside this ever shrinking volume.
We would see that at the edge (if we could see it) there's new mass and energy, but that would be obscured by what appears as the CMB for us.
> Heck, Hawkins radiation means black holes can evaporate. Does that correspond to a universa collapsing?
No, it corresponds to stuff disappearing from our universe, until someday nothing is left.
> Would matter falling into our black hole come shooting out of the white-hole we see?
We'd see it as being part of the Big Bang, behind the CMB, so we wouldn't see it.
> Would time on either side of the event horizon even be related?
Er, not in any way that we could observe, so it's not a question we could answer. But we could receive information from the outside, except that the CMB would hide it from our prying eyes.
The idea that any mass that will ever fall into our black hole all simultaneously appeared at the big bang doesn't feel correct. That suggests a very specific relationship between time on the inside and outside. There are at least two moments that are distuinishable on both sides. The singularity appearing, and the singularity dissapearing. Compressing all time on the outside into the big bang means weird things for the timing of when the singularity dissapears.
Take a proton for example. From the proton’s perspective, its creation and destruction happen in the same instant. From our perspective, it may travel through space for some period of time between the two events.
We’re not completely sure about the nature of gravity, but given how gravity seems to interact with spacetime, it seems at least plausible that time outside the singularity compresses to a single instant from the perspective of someone inside the event horizon.
It has to be the case that black hole evaporation means that mass-energy inside the black hole "disappears" from inside the black hole. It doesn't disappear from the rest of the universe, but if we are inside a black hole then we would "see" (if we could) that Hawking radiation means stuff disappears from our inside-a-black-hole-universe.
It's got a lot of ads, traffic arbitrage, floating unrelated videos and even back jacking...
To cross her course
Are swallowed by
A fearsome force
Through the void
To be destroyed
Or is there something more?
Atomized — at the core
Or through the Astral Door —
To soar…"
Its an interesting theory but to be honest, given the conditions of the event horizon, I don’t see HOW it could be proven.. That said I do feel this will turn out to be a nuance of the measurement itself but maybe that’s just my mind not comprehending the scales of what’s being measured here.
Hope that helps!
The density in the singularity (centre) of the black hole is in theory infinite. But the event horizon (the part where light no longer escapes) is not the singularity, it's simply where the gravity becomes so strong that light can't escape.
Think of it as the sun vs the planets - we're not in the sun, but we still feel its effects. The density of the solar system isn't the same as the density of the sun. This is bad analogy because the same mathematics/physics doesn't apply, but it should help you get the general picture based on your original assumption.
In general, the heavier the black hole, the less dense it is when measured from the event horizon. So in theory, it's possible to have a black hole so heavy that the event horizon contains the entire universe. In fact, the known universe is heavy enough to be a black hole 3 times the known radius of the universe. But as we know from stars that turn into black holes, just because something is heavy enough to be a black hole, doesn't mean it is one yet.