[HN Gopher] James Webb Space Telescope reveals that most galaxie...
___________________________________________________________________
James Webb Space Telescope reveals that most galaxies rotate
clockwise
Author : instagraham
Score : 250 points
Date : 2025-03-31 10:31 UTC (12 hours ago)
(HTM) web link (www.smithsonianmag.com)
(TXT) w3m dump (www.smithsonianmag.com)
| perihelions wrote:
| Also
|
| https://news.ycombinator.com/item?id=43372271 ( _" Is our
| universe trapped inside a black hole? This JWS Telescope
| discovery (space.com)"_, 56 comments)
| alenrozac wrote:
| At this point I'm open to believing our Universe is in a black-
| hole-like structure.
| d--b wrote:
| > 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!
| 0xEF wrote:
| I'm not well versed in celestial mechanics, but I see a lot of
| "we're in a black hole" comments so far, and I'm super curious
| as to whether or not we know why black holes prefer a direction
| of spin. Can you (or anyone, really) shed light on that?
| exe34 wrote:
| I think it would be more that the entire universe is in a
| black hole spinning in a certain direction.
| kingsleyopara wrote:
| Exactly and anything new entering the spinning black hole
| is likely to inherit its spin.
| iainmerrick wrote:
| It's not that black holes prefer a direction, it's just that
| they _have_ a direction at all. It 's one of the very few
| observable properties of a black hole.
|
| If I'm following correctly, the "we're inside a black hole"
| idea is a major reach, connecting at least two unrelated
| concepts (black holes could contain baby universes; black
| holes have spin). But it's a really interesting idea and not
| obviously wrong.
| f1shy wrote:
| Is inside the article:
|
| "A preferred axis in our universe, inherited by the axis of
| rotation of its parent black hole, might have influenced the
| rotation dynamics of galaxies, creating the observed
| clockwise-counterclockwise asymmetry," Nikodem Poplawski
| pandemic_region wrote:
| 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."
| d--b wrote:
| The convenience of black-boxy things!
| pixl97 wrote:
| I mean the universe in a black hole is one of the more common
| ideas in physics, though we don't have any evidence for it.
| So it's not surprising people pick it up and run with it.
|
| With that said, when the universe was younger things were way
| way closer so would it be possible for things like very early
| massive quasars to inject powerful magnetic fields in the
| otherwise dark universe at this time and bias matter falling
| into galaxies to one direction or another?
| bustling-noose wrote:
| Now if only we could see inside a black hole.
| snitty wrote:
| 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?
| scribu wrote:
| The point is that you'd expect a roughly even distribution of
| clockwise and counterclockwise spins, not all of them to rotate
| in the same direction.
| throwawaymaths wrote:
| wouldn't it be the case that you would see almost exactly
| 50/50 _if_ all galaxies had parallel axes _and_ rotated in
| the same absolute direction?
| 1oooqooq wrote:
| why? if you subscribe to big bang then all matter got the
| same "initial kick". would be easier to assume same spin?
| aurareturn wrote:
| So what caused the "initial kick" to favor one side?
| Aardwolf wrote:
| What causes a perfectly symmetric ball on top of a
| perfectly symmetric hill to roll down via one side?
| (Probably quantum randomness if everything else is
| perfectly symmetric)
| pixl97 wrote:
| What caused this universe to favor matter over anti-
| matter?
|
| So many unanswered questions.
| mnky9800n wrote:
| From my understanding, the big bang requires that the
| proto-universe was in a completely homogenous state that
| was then pushed out of that equilibrium for some reason.
| But that reason doesn't require non-zero angular momentum.
| It only requires that a the proto-universe was homogenous
| and now the universe isn't. And that is what separates pre
| and post big bang. I could be wrong, I am not a
| cosmologist. Would be happy to hear from one though.
| iainmerrick wrote:
| I was wondering the same thing -- "direction of spin" is
| ambiguous on its own, you also need to pick which direction is
| up.
|
| But if objective spin directions are roughly evenly split
| because the universe is isotropic, the spins from our viewpoint
| ought to be evenly split as well.
|
| If they're not evenly split, the universe must have a preferred
| axis, which would be an amazing discovery. I guess if the
| preferred axis just happens to align with our own galaxy, that
| would support the alternative theory that it's due to an
| observation effect such as doppler shift.
|
| Either way, it's incredibly cool to have such a simple but
| totally unexpected observation pop up out of nowhere.
| RotationPedant wrote:
| 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.
| Patient0 wrote:
| The actual paper makes more sense: "the number of galaxies in
| that field that rotate in the opposite direction relative to
| the Milky Way galaxy is ~50 per cent higher than the number of
| galaxies that rotate in the same direction relative to the
| Milky Way."
| keyle wrote:
| Potentially a very dumb question, but seeing the difference
| between cyclones and hurricane on earth (clock-wise, anti-clock-
| wise)...
|
| Does it mean that we are, potentially, on one of two poles(?) of
| the observable universe, if we're observing most galaxies around
| us rotating a certain way?
| Gooblebrai wrote:
| Regardless of if this is the case, the idea certainly blew my
| mind
| alfiedotwtf wrote:
| lol, I'm glad it wasn't just me that thought "woah wait. wtf
| did you just say??!"
| blackhaj7 wrote:
| Wow, interesting thought
| xtiansimon wrote:
| Universe of left-handed people.
| fennecfoxy wrote:
| That would be super cool to find out! And then it also begs the
| question, is there something at the center that unites the two
| poles? If so then what is it!
|
| It would also imply that our whole universe is rotating - the
| only reason this happens on Earth is because of our planets
| rotation and the Coriolis effect.
| thunder-blue-3 wrote:
| I've been following this news for the past couple of weeks--
| in essence your statement is what they are hypothesizing, and
| that the "something at the center that unites the two poles"
| might be that we are within a black hole.
| https://en.wikipedia.org/wiki/Black_hole_cosmology for the
| curious.
| nashashmi wrote:
| "The universe is an orb and that orb is rotating causing
| all the other stuff to spiral." This was a long held theory
| of mine because I could not understand why a galaxy would
| spiral.
|
| I think there is a men in black scene, where an alien is
| rotating the universe globe like a toy they are playing.
| rdtsc wrote:
| > This was a long held theory of mine because I could not
| understand why a galaxy would spiral.
|
| I think in general it would be unusual if they didn't
| rotate. Any large non-uniform mass of gas or rocks when
| colliding will induce some rotation. What is odd though
| is that for galaxies we see more of them spinning one way
| than another.
| eightysixfour wrote:
| Doesn't it _have_ to spiral? Think of the gravity well,
| anything not orbiting is just falling. The only things
| not racing towards the black hole at the center of the
| galaxy are the ones that are orbiting.
| nashashmi wrote:
| It can be directly sucked into the center. A spiral
| implies a lateral movement plus a centripetal force
| eightysixfour wrote:
| Right, I guess what I am saying is if it didn't spiral,
| it wouldn't be a galaxy for "long." It would just be a
| super massive black hole.
| soulofmischief wrote:
| Ok but what is making the universe spin? This kind of
| theory is turtles all the way down.
| irrational wrote:
| Is this getting into questions like "Where did the
| singularity come from?" and "What came before the
| singularity?". We don't have a way to answer these kinds
| of questions.
| askonomm wrote:
| It was my understanding that if two black holes collide,
| they just form a bigger black hole, but we know there's a
| black hole in our universe, which then would mean that
| there's a black hole inside of a black hole that did not
| merge with the parent black hole, right? Is that something
| that is considered possible?
| blueflow wrote:
| The inner black hole did not come from the outside, it
| formed inside and if i had to guess, it is stuck in the
| inside together with all the other matter, unable to
| interact with the outside of the outer black hole.
| askonomm wrote:
| Just thinking about this infinite recursion gives me the
| mental equivalent of a stack overflow.
| blueflow wrote:
| I don't think it is infinite - each universe can only
| have that mass/energy that fell into the outer black hole
| in the parent universe. At some level you'll inevitably
| have black holes with universes that do not have enough
| mass to form another inner black hole.
| idiotsecant wrote:
| How much mass is required to form a black hole in a new
| universe with perhaps different physical constants? It
| could be that 'ability to make black holes' is a
| prerequisite for successful universes in the way way that
| good genes are a prerequisite for successful organisms.
| The universes that fail to spawn black holes are 'dead
| ends' so any life is statistically likely to find itself
| in a black hole spawning universe.
|
| Maybe there is an 'incentive' for universes to form with
| physical constants tuned to produce black holes with the
| available energy in that universe.
| IngoBlechschmid wrote:
| This circle of ideals seems to be known as: https://en.wi
| kipedia.org/wiki/Cosmological_natural_selection
| soulofmischief wrote:
| Unless, although there's no reason to currently believe
| this, the energy requirements for physics are relative
| within each black hole, sort of (but not strictly) like
| how the speed of light is relative for all observers. And
| we can get a little crazier, and imagine a meta universe
| that is sort of like a Klein bottle in that it doesn't
| just recurse all the way down but somehow folds back into
| itself. Again, no current reason to believe anything like
| this but it's a mind-boggling to visualize.
| jug wrote:
| Maybe generating a stack overflow was the true depiction
| of God!
| lupusreal wrote:
| I'm under the impression that we really have no clue
| what's going on inside of black holes, so the most we can
| really say with confidence is that when two black holes
| collide they appear from the outside to now be a single
| black hole.
| colejohnson66 wrote:
| It's a reasonable assumption. If two solar masses
| collide, their masses tend to combine[^]. Just "look" at
| planets that smash into each other. Ergo, a more massive
| black hole.
|
| [^]: Ignoring ejections. But black holes also don't
| "eject" mass. Or maybe they do? Hawking Radiation is
| weird.
| soulofmischief wrote:
| Actually, they can shoot out relativistic jets at the
| poles. https://www.nustar.caltech.edu/page/relativistic-
| jets
| colejohnson66 wrote:
| But there, the black hole is ejecting _other_ mass near
| it, not its own.
| soulofmischief wrote:
| Mm, I didn't correctly interpret their comment. You're
| absolutely correct.
| colejohnson66 wrote:
| Yeah. I could've worded it better. By "ejections" I meant
| how, when two planets/moon sized masses collide, rocks
| shoot out into space. But because black holes have so
| much gravitational pull, everything theoretically just
| falls in.
| whamlastxmas wrote:
| *raises the question
| wjSgoWPm5bWAhXB wrote:
| Potentially a very good question!
| tiffanyh wrote:
| My own dumb question ...
|
| How does cyclones/hurricanes relate to being "on one of two
| 'poles'"?
|
| Do you mean hemisphere?
| jeffdn wrote:
| If all of the galaxies we see rotate the same way, are we
| "looking down" from a pole and seeing only those with the
| same rotation we have, as opposed to a more equatorial view
| that would be evenly split.
| vlovich123 wrote:
| But the universe isn't spherical. I'm not sure I understand
| this hypothesis as explained.
| pests wrote:
| But the observable universe roughly is.
| vlovich123 wrote:
| The observable universe is an illusory artifact of being
| an observer traveling at less than the speed of light. A
| constant distance in every direction is a sphere. That
| tells us nothing about the actual structure of the
| universe.
|
| In other words, your observable universe is different
| than mine and that's both spheres we're in the middle of.
| That suggests the universe itself probably isn't a
| sphere.
| SkyBelow wrote:
| Is it an illusory artifact or is it all that exists? If
| it can't be observed, it can't be tested, it can't be
| verified in any way or ever interacted with, then isn't
| it just an instances of Russell's Teapot and thus does
| not exist? What does it mean for science if existence
| isn't a binary property or one that we set as a truth yet
| is entirely untestable?
| pixl97 wrote:
| From all we can tell at this point is the universe is
| flat.
|
| https://en.wikipedia.org/wiki/Shape_of_the_universe
| Contax wrote:
| This along blows my mind: I picture this bin bang and
| everything expanding from that point and... that
| everything is now a sphere. In my mind. But it isn't?
| Yes, I know next to nothing but love thinking about all
| of this.
| jon_richards wrote:
| Picture an infinitely long piece of elastic. Now stretch
| that elastic.
| bigmadshoe wrote:
| Isn't this a 1d or 2d simplification?
| jon_richards wrote:
| Yes, 1d. But it's easier to go from a strip to a sheet to
| a block than trying to imagine an infinite block from
| scratch.
|
| The important part is that at any given point on the
| elastic strip, both sides are getting further away.
| _Everything_ else is getting further away.
|
| You might think if A-B-C-D are points on the tape and A-B
| are expanding and C-D are expanding, then B and C must be
| squished together, but the distance between them is also
| expanding. You have infinite elastic, but you also have
| infinite room to stretch it (even along the direction it
| already occupies). You now have A--B--C--D.
|
| It's tempting to think about that stretch from the point
| of view of the floor/table beneath the elastic, in which
| case some parts of the elastic move faster than others as
| they stretch, but if you always think from a point on the
| elastic, then the speed of the rest of the elastic
| depends on how far away it is. Stuff twice as far away
| moves away twice as fast. Stuff infinitely far away moves
| away infinitely fast. That's true for every point on the
| elastic. No bunching up.
| kirubakaran wrote:
| I usually just imagine an n-dimensional space and then
| substitute n as needed
| stouset wrote:
| OOMkilled
| SkyBelow wrote:
| It is often presented this way because models generally
| mix up the observable universe and the universe. One key
| notion is that we are at the center of the universe. Not
| the Milky Way, not the Sun, Earth is. Yet we know that
| Earth isn't at the center, so what is that? Because it is
| defined as our ability to travel from where we are at.
| Each of us could be considered at the center of our own
| observable universes, but this is a distinction we don't
| make because they overlap so closely that we don't have
| tools with the precision to tell them apart. I would
| guess that even aliens on the other side of Milky Way
| have an observable universe that overlaps so closely with
| our that they are equal to whatever level of precisions
| our tools allow for. Once you get to someone in a
| different galaxy, especially one that is moving away from
| us and not closer, then they have a different observable
| universe.
|
| But then, what is the universe? One way to think of it is
| to imagine that every galaxy has at least one intelligent
| species with their own observable universe. The universe
| is the sum of all observable universes. The very nature
| of how to sum them together, what it means to combine
| multiple sets of thing which include items that don't
| exist relative to other items in the set, is a question
| we can't really answer yet. Because of this, even a
| question like the size of the universe is unknown, and
| even the question of if more of the universe exists
| outside of the observable universe isn't simple to answer
| and gets into the nature of what it means to exist. If
| someone exists in the universe, but not in the observable
| universe, it becomes an instance of Russell's Teapot.
| x3n0ph3n3 wrote:
| How do you know?
| permo-w wrote:
| maybe _this_ is a stupid question, but is it possible that the
| big bang simply had some kind of clockwise angular momentum to
| it? how different is that idea from the black hole cosmology
| concept? I don 't really understand how the two fit together
| Reubachi wrote:
| I don't believe the current consensus is that motion from big
| bang imparted a spin on objects. Rather, that dark matter
| (mass) was "dropped" all over as a result of the bang, making
| gravitational hot spots. Millions of years of dark energy
| progression affects those hotspots, making a sort of ever
| expanding (yet perceptively slowing down) sink drain with
| water pouring into it.
| ziofill wrote:
| It's different because it's simpler to assume that the total
| angular momentum of the universe is zero. If one black hole
| is rotating one way there must be other stuff rotating the
| other way to counterbalance. If you assume instead that the
| whole universe has angular momentum, well, where did that
| come from?
| rdtsc wrote:
| > If you assume instead that the whole universe has angular
| momentum, well, where did that come from
|
| Would that be same kind of question as "where did the Big
| Bang come from?". That's a lot of energy that came from
| somewhere as well seemingly for no good reason.
|
| I also wondered immediately about dark matter; could it be
| that's where the counter-balance of momentum went? Like
| most galaxies spin one way and most dark matter would then
| have to spin the opposite way.
|
| I am not a physicist so this is all random guessing of
| course.
| RandomBacon wrote:
| > That's a lot of energy that came from somewhere as well
| seemingly for no good reason.
|
| I never finished the book, but this reminds me of _God 's
| Debris_ by Scott Adams which explores a philosophy of
| pandeism (where God annihilated itself and became the
| universe).
| exe34 wrote:
| Some say god is light. maybe it was a high energy photon
| that met its antiphoton.
| permo-w wrote:
| I say that god is just the universe
| platz wrote:
| Where did the the values of the coupling constants between
| the various fields come from?
|
| There are many parameters that do not have a reason for
| their value.
| weberer wrote:
| >If you assume instead that the whole universe has angular
| momentum, well, where did that come from?
|
| You can say the exact same thing about mass. Obviously it
| came from somewhere. And it could have taken angular
| momentum with it.
| eagerpace wrote:
| https://mapoftheuniverse.net
|
| While we don't believe we're the center of the universe, I
| believe we're limited by instrumentation to determine its size.
| Best guess now is 100B LY in diameter.
| A_D_E_P_T wrote:
| 100B LY is a little bit larger than the observable universe.
|
| But the observable universe is a fraction of the whole thing.
| The "best guess" right now is that the total universe is flat
| and has no end.
|
| If it's bounded, 100B LY is orders of magnitude below the
| most conservative lower-bound estimates, which I believe
| start at around 300-500x that size. (With huge error bars on
| all sides.)
| cozyman wrote:
| that's the neat part, it is though
| analog31 wrote:
| We're equidistant from the edge of the observable universe in
| all directions. One would think that puts us at the center.
|
| (But the same is true for someone sitting on another planet).
| ajross wrote:
| Some of that is a semantic thing about how one defines
| "distant", but this is not really required by GR. In fact the
| insight behind the emerging "timescape" theories is that the
| universe isn't flat or homogenous on large scales and that
| different regions have expanded at different rates. Their
| "edges" are equally old, but may not be not equally
| "distant".
| adolph wrote:
| > equidistant from the edge of the observable universe in all
| directions
|
| That seems like an example of "streetlight effect." _The
| streetlight effect, or the drunkard 's search principle, is a
| type of observational bias that occurs when people only
| search for something where it is easiest to look._
|
| https://en.wikipedia.org/wiki/Streetlight_effect
| jordanb wrote:
| It's not. Rather it's that every observer in the universe
| is at the center of their own light cone.
|
| The fact that we can not observe anything outside our light
| cone is well understood.
| hnuser123456 wrote:
| There is a dipole/toroidal universe theory:
| https://evolvingsouls.com/blog/toroidal-universe/
|
| Pardon the cheesy domain name, the content is very relevant.
| JumpCrisscross wrote:
| Which also implies the universe, or our section of it, is
| rotating. Which raises the question: where did that angular
| momentum come from?
| twojacobtwo wrote:
| Non-expert here, but I think any imperfect mass distribution
| with any attractive force would lead to a rotation. Which
| would mean, essentially, as soon as any imbalance happened in
| the early universe, some rotation was inevitable.
| vonneumannstan wrote:
| The same place the rest of the universe came from. A slight
| imbalance in the Matter-Antimatter distribution in the early
| universe
| MichaelDickens wrote:
| IIRC the Virgo Supercluster is gravitationally bound. Pure
| speculation but my guess would be that galaxies are revolving
| around the center of the Virgo Supercluster and this creates
| the galaxy-level Coriolis effect.
| thebeardisred wrote:
| Thanks for asking my question 8 hours in advance and allowing
| me to revel in the answers! :tada:
| peterburkimsher wrote:
| We're in the centre of the observable universe.
|
| The observable universe is the only true sphere.
|
| The observable universe is expanding into the unobservable
| universe.
|
| What would be interesting is to run a diff on the cosmic
| microwave background and the pictures from the James Webb space
| telescope to figure out where the true centre of the universe
| is, and derive the poles from there.
| jenadine wrote:
| > The observable universe is expanding into the unobservable
| universe.
|
| Is that so? My understanding is that it doesn't expend into
| something. And that it expend so fast that the edge of it
| becomes unobservable.
| peterburkimsher wrote:
| Space and time are related, and expanding rapidly since the
| Big Bang (though there was a time in the early universe
| when the expansion rate was faster).
|
| https://cds.cern.ch/images/CERN-HOMEWEB-PHO-2022-023-1
|
| Observing the edge is effectively looking back in time, to
| see the conditions of the universe closer to the time of
| the Big Bang.
|
| New telescopes keep expanding that edge, and new particle
| colliders (such as those at CERN or Fermilab) keep "bashing
| 2 rocks together to make fire" - recreating the conditions
| of the Big Bang to see what comes off.
|
| What I'm not sure about is whether the speed of light
| (assumed to be constant) is correlated with the size of the
| observable universe. Perhaps a physicist could shed some
| light on that question. Relativity means that galaxies that
| are moving at the speed of light away from one another (one
| travelling at c, another travelling at -c) have a relative
| velocity of higher than the speed of light (|c| + |-c| =
| 2c).
|
| There's also the theory of the One Electron Universe, which
| I quite like (though that reveals my bias as an electronic
| systems engineer). Perhaps what we see is the One photon
| universe. https://en.wikipedia.org/wiki/One-
| electron_universe
|
| Hopefully this rambling makes sense to someone!
| ck2 wrote:
| Wait, I get space expanding and accelerating.
|
| I never considered time expanding (and accelerating?).
|
| Is that even possible? What does that imply?
| peterburkimsher wrote:
| Finding a way to reverse the expansion of the universe
| would imply time travel being possible. It hasn't
| happened yet, but perhaps that's just a technological
| limitation. And if you ask my Mac, then Time Machine is
| very much possible - that's just the name of the backup
| system.
|
| The question starts to become very philosophical if there
| is a backup system for this universe. Everything being
| saved, for eternity, in infinite time. It would require
| very advanced computational power and storage, but it
| would probably work in binary (but that's just the kind
| of thing a computer engineer would say).
|
| Maybe, though, the observable universe is rotating
| clockwise around a centre that is in the unobservable
| universe, and time is just a measure of how many
| rotations have been made since the Big Bang.
| holoduke wrote:
| I thought the expansion of space which is faster towards
| the event horizon has no impact on the Lorents factor.
| But I might be wrong.
| peterburkimsher wrote:
| I think you're right, except for the spelling of Lorentz
| factor.
|
| The equation is on Wikipedia.
| https://en.wikipedia.org/wiki/Lorentz_factor
|
| The terms are: v is the relative velocity between
| inertial reference frames, c is the speed of light in
| vacuum, b is the ratio of v to c, t is coordinate time, t
| is the proper time for an observer (measuring time
| intervals in the observer's own frame).
|
| If we could compare the time as we know it (based on the
| SI unit of seconds using an atomic clock) against the
| time at the singularity at the centre of the universe, we
| could figure out whether we're in a black hole, whether
| we're at the event horizon, or whether we're outside.
|
| But we would have to assume space is a vacuum, which
| isn't entirely true.
| vonneumannstan wrote:
| Thats just a distinction between the Observable Universe
| and the Universe. The observable universe should be labeled
| "Our" Observable Universe as what is observable depends on
| where you are. Imagine a sphere growing outward at the
| speed of light, this is what is observable this region is
| aka the Hubble Volume. Right beyond the edge there just
| hasn't been enough time for the light to reach our
| location. No woowoo required.
|
| There are ongoing debates whether the actual Entire
| Universe is infinite or not.
| peterburkimsher wrote:
| There is only one Entire Universe; it's not a multiverse.
| And we observe it as a sphere, sized by the speed of
| light in every direction.
|
| Trying to see beyond the edge would be like trying to
| peer out of a black hole. It would probably look blue,
| like Cherenkov radiation. (but I'm biased, due to having
| blue eyes).
|
| If the Entire Universe is infinite, then it's eternal in
| time. And then we get philosophical again.
| kmoser wrote:
| Dumber question: would a galaxy that appears to spin clockwise
| appear to spin counter-clockwise when viewed from the other
| side? Does this imply that the real question is why galaxies'
| _relative orientations_ seem to favor more spinning in one
| direction than the other?
| smeej wrote:
| This is exactly the dumb question I came here to ask. So now
| I wait with you for a less dumb person to reply.
|
| My clock certainly seems to tick in the opposite direction
| when I look at it from behind.
| nuccy wrote:
| Answering to your and original question above: there are no
| poles (or axes of rotation) in the Universe. On large
| scales (think distances to include thousands and millions
| of galaxies each with billions of stars with even more
| planets) the Universe is uniform - isotropic and
| homogeneous [1]. It is expanding with acceleration in all
| direction in each and every point of its space, so there is
| no preferred direction thus in average we should have 50%
| of clockwise and 50% of counter-clockwise galaxies since
| orientation of those should also be absolutely random in
| average, unless something when the Universe was being
| created or evolving affected that balance.
|
| 1. https://en.wikipedia.org/wiki/Cosmological_principle
| ajross wrote:
| Yes, that's it exactly. There's a net asymmetry in the
| distribution of galaxy axes. "Clockwise" by itself is a
| relative term. This seems to be the paper in question:
| https://academic.oup.com/mnras/article/538/1/76/8019798
|
| 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.
| DonHopkins wrote:
| Unless you're looking at them from the other side, in which case
| they rotate counter-clockwise!
|
| Or maybe they're just billboard sprites, always facing the
| camera, with clockwise animations.
| misja111 wrote:
| Everybody here is talking about the black hole hypothesis, but to
| me it seems that the other explanation, a wrong assumption about
| the rotation of our own galaxy, is more likely: because it could
| explain 2 other problems as well.
|
| > "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."
| perihelions wrote:
| I don't understand how the 1e-16 Hz rotation of the Milky Way
| affects how we perceive other spiral galaxies' orientations.
| scythe wrote:
| >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
| perihelions wrote:
| - _" Doppler shift, astronomers expect galaxies rotating
| opposite to the Milky Way's motion to appear brighter"_
|
| But _how_ does that work?
| z33k wrote:
| 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.
| Nevermark wrote:
| From the perspective of us looking directly down on a
| parallel "plate" of a galaxy (with the other galaxy
| viewing us in the same way), relative differences in
| speed for the situation of same direction of rotation
| will be much smaller than for opposite directions.
|
| But between any point in one galaxy to another, just as
| much matter will be moving closer as moving away.
| Regardless of same or opposite rotations.
|
| But perhaps greater red shift and greater blue shift (as
| apposed to lesser of both) as a practical matter of
| telescopes vs. their cross spectrum sensitivities, means
| more light detected.
| IsTom wrote:
| I would assume that they're talking about redshift.
| like_any_other wrote:
| Yes, but one half of a galaxy would get redshifted, and
| the other blueshifted, no matter which direction it spins
| in. So why would that change its overall brightness?
|
| (Though one of the papers notes that the tiny change in
| brightness this causes isn't enough to explain the large
| difference in spin directions)
| marcosdumay wrote:
| The close and far sides get shifted too, and those have
| different brightness.
| perihelions wrote:
| No, 'like_any_other has it right: any physical system is
| 1-to-1 isomorphic with its mirror image, which is
| spinning the opposite direction.
|
| Whatever asymmetry you're visualizing for one galaxy, its
| mirror-image galaxy is equally physical, and possesses
| the same asymmetry.
| tomrod wrote:
| Relative motion to the center. 230 km/s is fast.
| perihelions wrote:
| Then how does linear motion do it?
| Aardwolf wrote:
| But then on the other side (hemisphere) we'd move the other
| direction (towards vs away), so wouldn't the opposite
| effect be expected there, more counterclockwise galaxies?
| 1oooqooq wrote:
| that's trivial to model... if anyone looking for a phd topic
| that sounds complex but only involves basic trig. (conclusion
| will probably be a No)
| dodslaser wrote:
| Did they also check in the northern hemisphere of the observable
| universe?
| worldsayshi wrote:
| Clockwise relative to what? Does the universe have an "upwards"
| direction?
|
| Or is it just relative to all the other galaxies?
| andrewaylett wrote:
| 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.
| MichaelZuo wrote:
| 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?
| namaria wrote:
| That's the thing, we don't know any reason for a preferred
| spin and assumed it would be equally distributed. So this
| is an interesting fact.
| MichaelZuo wrote:
| There doesn't need to be a reason, just random chance
| from gasses shifting around is sufficient.
| hnaccount_rng wrote:
| I think you are misunderstanding the point being made:
| The _only_ random chance that is part of current models
| is "quantum uncertainty at big bang time" and we can give
| upper bounds for the variations that can be explained
| from that. So what's really being said here is "We found
| a significantly larger discrepancy between Milkyway-
| corotating galaxies and Milkyway-counterrotating galaxies
| than can be explained by ~initialisation randomness"
| MichaelZuo wrote:
| That doesn't make sense, they can't be assumed to have
| behaved like ideal gasses, thus turbulence alone can
| cause significant uncertainties.
|
| Let alone all other possibilities combined.
| soulofmischief wrote:
| It's still of great interest to understand why exactly
| symmetry broke, and how this news might affect the
| cosmological principle.
| worldsayshi wrote:
| > 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.
| deepsun wrote:
| You are correct, we are indeed at the center of the
| universe.
|
| Hence the farther we observe stuff, the earlier in time it
| happens. And if an observer moves to a different location,
| they will still be at the center of the universe (aka light
| cone).
| worldsayshi wrote:
| > And if an observer moves to a different location, they
| will still be at the center of the universe (aka light
| cone).
|
| That doesn't make sense for this particular context
| though. The direction of "up" of another galaxy doesn't
| change depending on where you are as an observer...
|
| Then again, it's only two-thirds of the galaxies that
| have "up" facing us - which isn't that surprising. If
| something like 99% of their "up" was facing us it would
| seem more special.
| okdood64 wrote:
| So it would've been more "broadly" true to say: JWST
| discovers that most galaxies rotate in the _same_ direction?
| xeornet wrote:
| Sorry if it's a dumb question, by why would we expect an
| equal number? Doesn't that assume that we consider ourselves
| at the centre of our observable universe?
| schoen wrote:
| https://en.wikipedia.org/wiki/Copernican_principle
|
| It seems to have caught on, but one could still doubt its
| applicability to all phenomena at all scales.
| mech987876 wrote:
| My best guess would be using a standard coordinate system such
| as
| https://en.m.wikipedia.org/wiki/Supergalactic_coordinate_sys...
| Patient0 wrote:
| The actual paper makes more sense: "the number of galaxies in
| that field that rotate in the opposite direction relative to
| the Milky Way galaxy is ~50 per cent higher than the number of
| galaxies that rotate in the same direction relative to the
| Milky Way."
| zurfer wrote:
| Complete layman's question: If we would indeed be inside a black
| hole wouldn't we be able to observe new energy and matter
| entering?
|
| Related question: the horizon of a black hole is expanding when
| the mass increases. Could this map to the expansion of our
| universe, which seems to expand faster and faster?
| jagged-chisel wrote:
| I don't think we know enough about relative time from outside
| our universe. Our 15 billion years could be the parent
| universe's one second.
| thro1 wrote:
| What about black hole new mass/energy converting into
| orthogonal space ??? ( ..is it part of _Principia Unitas_ ??).
| floxy wrote:
| >If we would indeed be inside a black hole wouldn't we be able
| to observe new energy and matter entering?
|
| https://en.wikipedia.org/wiki/Dark_energy
| like_any_other wrote:
| > Due to an effect called the Doppler shift, astronomers expect
| galaxies rotating opposite to the Milky Way's motion to appear
| brighter
|
| How does this work? The page it links to doesn't explain why
| rotation would matter.
|
| Edit: To clarify - one side of the galaxy would be moving towards
| us, and one away from us, no matter which direction it spins in,
| so this should not affect the average brightness of the entire
| galaxy.
|
| The original paper
| (https://academic.oup.com/mnras/article/538/1/76/8019798?logi...)
| links to a few papers discussing this, among them
| https://www.mdpi.com/2073-8994/15/6/1190 It doesn't answer my
| question (or if it does, I didn't understand it), but it gives a
| magnitude for the expected effect on brightness - 0.6%. I do not
| think that would explain the 1:2 ratio of observed spin
| directions.
| ceejayoz wrote:
| One side is moving away from us, the other towards. This means
| their relative speeds are different, detectably so.
| perihelions wrote:
| How are you linking that effect to the spin orientation of
| the Milky Way galaxy? Where is the all-sky anisotropy coming
| from?
| anomaloustho wrote:
| I went to give a similar answer and realized that - in the
| instance that the two galaxies are sideways facing each other
| and with the text saying "it gets brighter" not "one side
| gets brighter" - I'm not sure if this is the actual answer.
|
| I can't figure out why the Doppler Shift would make the
| entire galaxy brighter. I assumed it would make the rotation
| side spinning towards us brighter. But also redshift the side
| spinning away.
| tomr_stargazer wrote:
| I think this may be a subtle reference to what is usually
| called "relativistic beaming" or "Doppler beaming" [0], though
| I normally associate this effect with matter that is moving
| quite close to the speed of light.
|
| [0]: https://en.wikipedia.org/wiki/Relativistic_beaming
| like_any_other wrote:
| perihelions [1] phrased it best - a galaxy spinning clockwise
| is just the mirror image of one spinning counter-clockwise.
| So why should mirroring change brightness? I don't really
| understand why Doppler beaming would cause this (though one
| of the papers did also mention it).
|
| The other question is - what does the rotation of our own
| galaxy have to do with it? Let's keep the Solar system as is,
| and mirror the rest of the Milky Way around it, so that it is
| now spinning the opposite direction. Why should this affect
| the apparent brightness of other galaxies? Especially since
| the Solar system is effectively moving in a straight line, on
| the scale of a human lifetime.
|
| [1] https://news.ycombinator.com/item?id=43535285
| lostmsu wrote:
| This is only obvious when you yourself are not moving on a
| curved trajectory.
|
| In GR curved trajectories lead to "weird" observations. For
| instance, I'd expect the side of the remote galaxy that is
| closer (visually, for you as an observer) to the center of
| your galaxy to be gravilensed slightly more than the other
| side. Because the effect is non-linear, it does not just
| compensate when sides are reversed.
|
| P.S. Not claiming this has any significant effect on the
| described phenomenon, just that mirror symmetry does not
| apply.
| ordu wrote:
| Well, I don't know physics, but from I heard of it, there are
| two kinds of phenomena that are sensitive to a rotation. One is
| quantum particles, they have fixed spin, but won't delve into
| that topic, because I suspect that their "spin" is like the
| charm of the charm quark, probably physicists just liked the
| sound of a word and used it. But there is one other thing I
| heard about: electromagnetism. If you run charged particles in
| circles, they create magnetic field that is directed
| perpendicularly to the circles, and the magnetic field feels
| different depending on the side of the circles being observed.
|
| I see no way it influences the light emitted, but maybe I heard
| just too little of physics? BTW, does the direction of magnetic
| field of galaxies correlate with the direction of their
| rotation?
|
| edit: Ah, maybe magnetic field can polarize the light? And when
| you have two magentic fields they polarize in one direction or
| in two different, and maybe it influences observed brightness
| of the light? Or maybe it is just an uninformed guess?
| andrewclunn wrote:
| Time and time again, we are beginning to come to the realization
| that our entire observable universe is not the whole picture, and
| we are almost certainly seeing only a localized portion of a much
| larger and grander universe.
| seydor wrote:
| Does it need to be that the whole universe started with rotation,
| or that our visible part of the universe has a common ancestor?
| over_bridge wrote:
| 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
| yboris wrote:
| _Cosmic Rays May Explain Life's Bias for Right-Handed DNA_
|
| "the rapid decay of pions is governed by the weak force -- the
| only fundamental force with a known mirror asymmetry"
|
| https://www.quantamagazine.org/cosmic-rays-may-explain-lifes...
| anomaloustho wrote:
| Isn't there a different observation for why planets tend to
| orbit in the same direction in a solar system?
| deepsun wrote:
| It's easily provable that any matter rotating other way gets
| expelled or thrown to center (Sun). So majority wins.
| albertzeyer wrote:
| 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?
| hhjinks wrote:
| 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.
| nabakin wrote:
| Could it be that the observable universe is one of these
| stable local pockets and the antimatter to balance it out
| is simply not observable to us?
| SkyBelow wrote:
| Potentially, but it seems like an untestable hypothesis
| by itself.
| ben_w wrote:
| Mathematically possible.
|
| If you flip 2n fair coins, you expect n+d heads and n-d
| tails, where d is (IIRC) sqrt(n/2). Going much away from
| that becomes infintessimally unlikely.
|
| Probability is a subject famously easy to get wrong, so
| be careful with what I'm about to suggest: I *think* you
| could argue that in the moment prior to the inflation
| epoch spreading everything out just enough that pair
| production stops*, any given particle in our horizon is a
| coin toss of matter or antimatter.
|
| Number of observed atoms in the universe is about 6e79 (h
| ttp://www.wolframalpha.com/input/?i=how%20many%20atoms%20
| in...), so 6e79 = sqrt(n/2) -> n = 7.2e159 due to
| protons, and the same again for electrons; as we don't
| see significant signs of antimatter, any around must have
| annihilated a long time ago, so in this scenario we
| should expect to see ~7e159 (red-shifted) photons from
| the supermajority of particles which have annihilated.
|
| It's outside my field to know how that compares to
| cosmologist's observations.
|
| * won't that be at different times for protons/neutrons
| and electrons?
|
| I can't get good answers on the expectations for either
| "why are protons and electrons counts the same" or "what
| is the observable consequence if they're not?"
| BlarfMcFlarf wrote:
| Not a physicist, but here is my understanding of the
| cosmology physics:
|
| High energy can spontaneously form matter antimatter pairs.
| In the early universe, the heat of the universe was very
| high, so this was common, constantly happening.
|
| The problem as always if fine tuning. If the early universe
| was 60-40, that would be understandable. If the early
| universe was precisely 50-50, that's fine too. But the
| universe was 50.0001-49.9999 or something like that, and then
| all annihilated. It's too big a difference to easily be
| random chance, and too small a difference to be easily
| explained by a starting condition what wasn't precisely tuned
| by some mechanism.
| permo-w wrote:
| but I was under the impression that equal parts of matter and
| antimatter annihilate, which would make a 50:50 system remain
| as such, which is why its such a mystery?
| btilly wrote:
| In all known physical processes, the baryon number is
| conserved. Particles with a positive baryon number are the
| heavy particles in matter. Think protons, neutrons, and so
| on. Particles with a negative number are antimatter. Think
| antiprotons, and antineutrons. And particles with a 0 baryon
| number are not made of quarks. Think leptons like electrons
| and neutrinos, or bosons like photons and the Higgs boson.
|
| This means that all known ways to create or destroy matter,
| also creates or destroys an equal amount of antimatter.
|
| It turns out that most attempts to extend the Standard Model
| allow violations of baryon conservation. This could explain
| the dominance of matter in our universe. However none of
| those attempts have been able to make any predictions that
| matched experiment. And so it remains true that all known
| physical processes perfectly conserve the baryon number.
|
| (It is also possible that baryon number really is conserved,
| and dark matter is actually dark antimatter. But we lack a
| theory of what dark matter could be that predicts this.)
| adrian_b wrote:
| Even if in the strong, weak and electromagnetic
| interactions the baryon number is conserved, there is the
| interesting fact that for the 8 particle set composed of
| the 3 kinds of u quarks, 3 kinds of d quarks, 1 electron
| and 1 neutrino, the sum of all kinds of quantities that are
| expected to be conserved, like electric charge, color
| charges and spin sum to zero. This set of 8 particles is
| also equivalent with the set of the components of one
| proton, one neutron, one electron and one neutrino.
|
| This property of this set of 8 particles is analogous to
| the similar property of the set of 2 particles composed of
| a particle and its anti-particle, and to the similar
| property of the sets of 4 particles that can be involved in
| a weak interaction (the intermediate weak bosons convert
| one 4-particle interaction into a couple of 3-particle
| interactions, but when looking at the overall inputs and
| outputs, all the weak interactions are 4-particle
| interactions), which ensure the conservation of various
| quantities over such interactions.
|
| This means that it is possible to conceive an additional
| kind of interaction, which unlike electromagnetic
| interactions between 2 particles and weak interactions
| between 4 particles, involves 8 particles, so it has a much
| smaller probability of occurring, i.e. it is a much weaker
| interaction than the weak interaction, and through which,
| when provided with enough energy, quarks + electrons +
| neutrinos could be generated simultaneously without
| generating anti-matter.
|
| While there is no evidence yet for such an interaction, it
| is conceivable that at least during the circumstances of
| the Big Bang, such an interaction could have existed, so
| all the quarks and leptons could have been generated from
| some unknown bosons, just with enough initial energy and
| with conservation of all quantities for which there are
| solid reasons to believe that they must always be
| conserved, like energy, linear momentum, angular momentum,
| electric charge and color charges. (Unlike for the baryon
| number, for which there is no other reason to believe that
| it must be conserved, except that the strong, weak and
| electromagnetic interactions happen to have this behavior.)
| mystified5016 wrote:
| You would expect a 50/50 ratio because when energy is
| converted into matter, it's typically in the form of
| matter/antimatter pairs.
|
| There's nothing special about matter or antimatter. Same
| energy, just opposite charge. All else being equal, they
| _should_ be created in equal amounts. As far as we 're aware,
| there is no special property that would make the universe
| preferentially create more matter than antimatter.
|
| There's also no requirement that the configuration of matter
| and antimatter be "stable" for whatever definition you want
| to apply. The only rule is that conserved quantities stay
| conserved.
| otikik wrote:
| 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
| gerad wrote:
| Dark matter / regular matter
| Ygg2 wrote:
| > Left vs right handed molecules
|
| Organic chemistry found on meteors shows that non-terrestrial
| sources are equally left vs right-handed.
|
| However, the rest might be caused by one or more errors in our
| premise. The most likely culprit being cosmological principle.
| stainablesteel wrote:
| there's also that famous experiment by Chien-Shiung Wu,
| veritasium did a video on it somewhere
| anal_reactor wrote:
| I honestly start thinking that the idea "everything should be
| symmetric in some way..." is completely wrong, and an example
| of wishful thinking "...because it would be cool if it did".
| Even if nature is in some way balanced on a scale large enough,
| it's extremely unlikely for us not to be in some local pocket.
| Most likely we're a part of some bigger structure that has
| certain properties, and this affects our perception of the laws
| of physics.
| Nevermark wrote:
| > Most likely we're a part of some bigger structure that has
| certain properties, and this affects our perception of the
| laws of physics.
|
| Which would also be the reason we have the laws of physics we
| do in general.
|
| Anything seemingly ad hoc in our universal (from our vantage)
| viewpoint is potentially explainable as a pocket among all
| other possible distributions/combinations of relations.
| brador wrote:
| This to me indicates the primordial particle was spinning
| clockwise.
| lioeters wrote:
| How would you even define what is clockwise or not if there is
| no other particle as a reference? You can look at it from the
| other side and say it's spinning in the opposite direction.
|
| I think it's enough to say that it was spinning. There was an
| imbalance tending toward a direction.
| damnitbuilds wrote:
| 1. Are they really saying "Because we are in a universe with a
| preferred spin and black holes have spin, we must be inside a
| black hole?" Tenuous, no?
|
| 2. If we are inside a black hole, where is the singularity?
| mnky9800n wrote:
| If the universe is bounded by regions that are further away
| than the speed of light has time to reach us then that would be
| an ideal place to look for a singularity. unfortunately it is
| unmeasurable since so far the speed of light is a hard boundary
| for what we can measure.
| layer8 wrote:
| Inside a black hole just means inside its event horizon. The
| singularity can still be arbitrarily far away from that horizon
| (if the black hole is correspondingly large). The volume
| enclosed by the event horizon may be larger than our
| cosmological horizon (i.e. how far the speed of light allows us
| to see, given the finite age of the universe.) And the
| singularity of a black hole isn't "where", it's "when". The
| singularity of a black hole is in the _future_ of all particle
| trajectories inside the event horizon.
| floxy wrote:
| > where is the singularity?
|
| Maybe black holes don't have a singularity:
|
| https://arxiv.org/abs/2312.00841
| belter wrote:
| This study does not conclusively prove most galaxies rotate
| clockwise...Just has a somewhat strong observation of asymmetry.
| Other studies that the paper mentions, and criticizes, did not
| observe it.
|
| Study is at around 3s (like 62 heads in 100 flips). It is more
| likely that future studies disprove it, and this is an issue with
| the methods, if I am of the betting type... :-)
| pushreply wrote:
| So, there is a visible order about this matter. That they are
| "rotating", instead of, for example, "Z-Pattern" movement.
| Amazing.
| vincnetas wrote:
| But rotation direction depends on the observer. If i see galaxy
| spinning clockwise, this means someone observing galaxy from
| behind it sees it rotating counter clockwise. So are we just
| located so in the universe that we see 2/3 spinning clockwise and
| another counter?
| Patient0 wrote:
| The actual paper makes more sense: "the number of galaxies in
| that field that rotate in the opposite direction relative to
| the Milky Way galaxy is ~50 per cent higher than the number of
| galaxies that rotate in the same direction relative to the
| Milky Way."
| floatrock wrote:
| So 1/3 MilkyWay-Wise, 2/3 Counter-MWW?
|
| Or is it? I hate these percent-relative word games things...
|
| - Let x = "num MWW"
|
| - then "num CMWW" = 1.5x ("50% higher than x")
|
| - x + 1.5x = 1
|
| - x = 0.4
|
| So 40% is MWW, 60% CMMW?
| wruza wrote:
| Correct, I guess. 40/100 x 1.5 = 60/100. For 1/3 and 2/3 it
| must have been 100% higher.
| permo-w wrote:
| this is a hard one for me to instinctively understand
| spatially, so I'm imagining myself stood in a room with arrows
| pointing left and right. if I have 3 arrows facing left in
| front of me and behind me I have 3 arrows facing left -- from
| my perspective when I turn around -- then I step past one of
| the arrows and now I have 2 left facing on one side and then in
| front of me what was now a left arrow is a right arrow, so now
| there's 5 lefts and 1 right. so extrapolating that, the
| observation is possible, but it still doesn't explain the
| imbalance, does it? you would expect most places in the
| universe to have a roughly even distribution from any
| perspective, I think?
| jncfhnb wrote:
| No I don't think so
|
| Once you have a few dimensions on a normal or other
| distribution there's not a lot of content that's in the
| middle.
| rob74 wrote:
| It just occured to me that "rotation direction" is a pretty
| coarse measurement. Actually, you could look at the _angle_ of
| a galaxy relative to ours, where (let 's say) 0deg is viewed
| exactly from "above" (rotating clockwise), 180deg is viewed
| exactly from "below" (rotating counterclockwise), 90deg/270deg
| is viewed side-on etc. How about some stats based on this
| parameter?
| kevinb9n wrote:
| This was my thought too
| q_andrew wrote:
| This is actually why rotational math is more complicated in
| 3d than you would expect. It's something game developers get
| used to, because accessing and modifying a rotation requires
| knowing what the orientation is relative to a fourth axis.
| That's what a quaternion is. In the situation of this story,
| it's in reference to the milky way's vertical axis.
| smeej wrote:
| What does "above" or "below" even mean in the context of
| something without a top or bottom? Or are you _defining_
| "above" to mean "the vantage point from which the galaxy
| appears to be rotating in the direction of earth clocks" for
| the purpose of this question?
| BubbleRings wrote:
| I was disappointed that the article only once mentioned "from our
| perspective" in relation to the spin of galaxies. One of the most
| fascinating things that you first learn about when you try to
| understand relativity, is the fact that there is no "still" point
| in the entire universe. Out in space, the point in space one foot
| in front of your space suit's helmet can be called still by you,
| but it is just as reasonable to call a rock racing by you at a
| million miles an hour the central still point, where all other
| motion in the universe can be measured against. Because there is
| no absolute still anywhere. And when you understand that, that's
| when all these cool concepts can then be described, related to
| time changes that happen between two locations when the relative
| speed difference between the two objects or locations approaches
| the speed of light. (So you can return from your trip to Alpha
| Centuri and meet your great great grandson who is older than
| you.)
|
| And just like there is no still point in the universe, there is
| no up or down. So yes, it may be true that, IF you select a
| couple of arbitrary points in the universe to be up and down,
| THEN you can count how any galaxies spin left vs right. And it is
| way cool to find out that it doesn't appear to be 50/50, and to
| wonder about why. But I think the article author did the readers
| a disservice by glossing over the "no up or down" fact.
| symmetricsaurus wrote:
| The result is only significant to 3.39 sigma. Pretty good chance
| this is just a random fluctuation that will go away if you look
| at more galaxies.
| BlackFly wrote:
| This was also my thought, since selection bias seemed like a
| good explanation as well. The survey only covers 220 square
| arcminutes out of a total of about 148 million. Interesting
| data point though, definitely seems like something that one
| should measure!
| kerkeslager wrote:
| Another potentially dumb question: what does it mean for a 3d
| body to rotate clockwise? Doesn't a clock, viewed from its back,
| turn counter-clockwise? So is this just from James Webb's
| perspective that they rotate clockwise?
| abecedarius wrote:
| Yeah, the headline is misleading for just that reason. But
| rotation in 3d does have an unambiguous orientation which we
| call right-handed or left-handed (the "right hand rule" if
| you're unfamiliar with this). I don't know which orientation
| our galaxy's rotation has, the article only says it's opposite
| the majority in this sample.
| CPLX wrote:
| I was reading this and thinking, what if there's no such thing as
| scale. Like, obviously there is in some sense, but what if
| there's some kind of theory of relativity for scale as well,
| maybe scale is relative to gravity and gravity isn't constant or
| something like that. So for example a universe as detailed as
| ours with sentient beings and all that could exist inside a
| quark, and we could in fact be living inside a proton or
| something, seen from someone else's perspective. And it's that
| level of detail, forever, in every direction.
|
| Or maybe not, anyways back to work.
| klysm wrote:
| So the universe is left handed?
| gwbas1c wrote:
| I used to read a lot about the history of science as a kid.
|
| The one thing that stuck with me is how frequently things we
| believe to be true are disproven.
|
| This does not surprise me:
|
| > "If that is indeed the case, we will need to re-calibrate our
| distance measurements for the deep universe,"
| singularity2001 wrote:
| approximately 60% of the 263 galaxies examined were found to
| rotate clockwise, while about 40% rotated counterclockwise. The
| study's results have a significance level of approximately 3.39
| sigma, indicating a moderate chance that the findings could be
| due to random fluctuations
| wtcactus wrote:
| The linked article is written in an absurd way. Clockwise is not
| a fundamental measurement, it's relative to the viewer.
|
| What the original article explains, is that this is relative to
| our observer point of view (obviously).
|
| It's still very interesting, since, disregarding any potential
| interaction in our local group, randomness was expected and we
| should see around 50/50 rotating either way unless one of the
| explanations came into play.
| credit_guy wrote:
| I wonder if it's already April's Fools Day in some parts of the
| world. The hands of a clock move clockwise if seen from the
| front, but counterclockwise if seen from the back.
| coffeecantcode wrote:
| Coming from a place of complete ignorance, are there indicators
| in galaxies that determine a top/bottom for lack of better
| words?
|
| I can't think of any that would make much sense as top/bottom
| would mean that there needs to be a relative universal point to
| reference and as far as I know, that doesn't exist.
| tiagod wrote:
| The article states that the problem is that they looked at
| random galaxies, 1/3 were moving one way and 2/3 the other.
|
| If the distribution was truly random, and the universe is
| isotropic, we should see roughly 50/50.
| gerad wrote:
| On the antipodal side of the universe they mostly rotate
| counterclockwise. ;-)
| mapt wrote:
| Fascinating.
|
| Did it require JWST to notice this, or did we just _not check_
| until now?
|
| Is there a notable asymmetry in, say, the spin directions of
| galaxies contained in the Hubble XDF?
|
| EDIT:
|
| This doesn't make a lot of sense. Lior Shamir has written that a
| lot of unrelated sky surveys recently have shown an asymmetry in
| the past few years, but only down around ~2%.
|
| https://www.mdpi.com/2073-8994/16/10/1389
|
| https://aas.org/sites/default/files/2020-05/lior_aas236.pdf
|
| JWST's asymmetry in both early work and more recent deep fields
| is more than an order of magnitude stronger.
|
| EDIT2: Notably they show anisotropic asymmetry: The galaxies are
| different rotations when you look in different directions, with
| something like +6% in one direction and -5% in another. But still
| nothing like the +50% now being reported as a general feature.
| stainablesteel wrote:
| so i guess the underlying assumption is that this looks out from
| out perspective in a single static orientation, because this says
| nothing to me about their orientation which i think is what
| they're trying to convey by saying clockwise?
|
| or i suppose this is clockwise/counterclockwise in regards to the
| direction they're moving in?
|
| 2/3 doesn't seem that significant if they think it should be a
| 50/50 split, we might just not be seeing enough
| lupusreal wrote:
| Is this a robust finding? I heard something about this apparent
| discrepancy a week or so ago, and it was dismissed as probably
| just an artifact of dodgy classification and the paper's author
| was a bit of a kook, a computer scientist who was delving into
| cosmology to find evidence of the simulation hypothesis.
| tlogan wrote:
| Could this be related that the weak force only interacts with
| left-handed particles (and right-handed antiparticles)?
| RobertRoberts wrote:
| Everything turns clockwise from a specific perspective... that's
| what is interesting here, perspective and consistency.
| slicktux wrote:
| Could an equivalent of the Coriolis Force be at play here?
| 1970-01-01 wrote:
| Spin a coin on top of a glass table. Observe it from the top, and
| it spins either clockwise or anticlockwise. Observe it from the
| bottom and it's the opposite. There are no tables in space.
| Objects tumble while rotating. It seems we are measuring
| rotations using a fixed perspective when there is no reason to do
| so
|
| https://www.comsol.com/blogs/why-do-tennis-rackets-tumble-th...
| richwater wrote:
| The paper measures rotation relative to the Milky Way galaxy.
| hnuser123456 wrote:
| If there were 10 pennies and 7 of them were spinning the same
| direction, you might say one direction appears to be favored.
|
| Spiral galaxies spin, they do not tumble unless hit by another
| galaxy.
|
| Elliptical galaxies are like gravitational convection and don't
| really have cohesive "rotation", however.
| metalman wrote:
| must be something left out, because a galaxies r/l rotation is
| dependent on which side it is bieng viewed from, and since the
| are unlabled as to face and back, what is the basis for the
| handedness of something spinning in the void, with presumably
| most of the galaxies tilted at every angle and orientation
| possible other than aligned with ours. and 263* galaxies is zero
| galaxies when divided by the minimum number of galaxies, it's not
| a significant sample * number in study
| sivm wrote:
| We're six black holes deep
| tagami wrote:
| If you look at the galaxy from the other side, wouldn't it be
| counterclockwise?
| bigmadshoe wrote:
| Yes, but I think the interesting thing is that there are a
| greater number of galaxies spinning one way than another.
| soulofmischief wrote:
| What if we're just upside down? :)
| geor9e wrote:
| TIL the universe has a specific "up" direction to even call
| things counterclockwise. I guess I should have already known this
| from Star Trek's quadrants
| https://en.wikipedia.org/wiki/Galactic_coordinate_system
| 93po wrote:
| sorry if someone already asked this, but what is clockwise when
| there's no "up"? The earth axis is like 60 degrees off the axis
| of milky way, so it's not clear what the frame of reference is.
| pixl97 wrote:
| In theory it doesn't matter what the frame of reference is.
|
| Instead of thinking of it like spin, think of it like heads or
| tails. Both are binary measures and frame of reference doesn't
| matter. For example if you're flipping a penny on a glass table
| and someone is looking from the bottom, they'll see the same
| ratio as you.
|
| In a fair universe you'd expect pretty much a 50/50 heads/tails
| clockwise/anti-clockwise outcome. But instead we something like
| 66/34 or 75/25. The actual direction of spin doesn't matter.
| The fact the measurement is unbalanced does.
| rambojohnson wrote:
| got it.
| bilsbie wrote:
| Maybe anti matter galaxies would spin the other way
| rezmason wrote:
| Shouldn't the galaxies in the northern and southern hemispheres
| spiral in opposite directions? /s
| wojo1206 wrote:
| US left-handed presidents are also over-represented. This is
| another reason to feel special in our neighborhood.
| GuinansEyebrows wrote:
| Correction: Oops, The Telescope Was Just Spinning Counter-
| Clockwise, Our Bad
| martini333 wrote:
| My clock also runs clockwise, when seen from one of two sides...
| jiggawatts wrote:
| They analysed only a small patch of sky, which could have a local
| relative rotation compared to our region of space.
|
| Real science will be when they survey the entire sky, with many
| small deep-field images.
| wokewombat wrote:
| isn't counterclockwise same as clockwise whe viewed from the
| other side?
| nabla9 wrote:
| > The same solo author (a computer scientist) has made many
| similar claims based on a variety of datasets. Often coming to
| completely contradictory conclusions. Some of these claims have
| been followed up by astronomers, who found errors in his analysis
| and poor statistical tests. His claims have been discussed in
| this sub before. Independent studied have found no significant
| evidence of anisotropy.
|
| https://academic.oup.com/mnras/article/534/2/1553/7762193
|
| https://ui.adsabs.harvard.edu/abs/2021ApJ...907..123I/abstra...
|
| https://ui.adsabs.harvard.edu/abs/2017MNRAS.466.3928H/abstra...
|
| >Take his claims about JWST as an example. In 2024 he wrote a
| paper about some early data, claiming to find more galaxies
| rotating with the Milky Way. He claimed based on a sample of just
| 34 galaxies that the signal was significant. Now he has looked at
| a wider dataset of the same area, which should allow him to
| verify his analysis. But it shows exactly the opposite, more
| anti. So he writes a paper saying this new result is definitely
| significant but doesn't reflect on the fact he has written two
| papers which contradict each other. He has failed to reproduce
| his own result. The take away is that his results are not as
| significant as he claims. He's also looking at a tiny area, and
| nearby galaxies can have correlated spins. He doesn't take this
| into account either. There are multiple JWST fields in different
| directions he could examine in different directions to test his
| claims, there are two JADES fields, but he only publishes one.
|
| >I do wish the MNRAS editors would take measures to stop
| publishing low quality claims like this without more robust
| review. If you look at the text, it's largely repeating results
| from his old papers. There's very little discussion of the new
| results.
|
| source:
| https://www.reddit.com/r/cosmology/comments/1ja9i53/the_dist...
| iainmerrick wrote:
| Thank you. That's a shame, it was a cool-sounding story, just
| unlikely enough to sound plausible.
| twothreeone wrote:
| Wow and not even 24 hours after Trump takes aim at the
| Smithsonian.
|
| *) The article is from March 17.
| smath wrote:
| Several folks here have recognized that the spin direction
| depends on whether you look at the plane of the galaxy from
| 'above' or 'below'. One thing I didn't see in the article is how
| the two types of galaxies are distributed across the 3D spherical
| coordinates when viewed from the earth (or rather from the JWST).
|
| Im thinking: what if there are a bunch of massive objects like
| black holes in certain directions that are causing the light to
| bend in a certain way. So what would normally be light coming
| from the top of the galaxy plane, is actually light reaching us
| from the bottom of that plane. Would this slew the distribution
| of the spin one way - I don't know.
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