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> stars Galaxies. And determining the approx relative distance of distant galaxies is in fact easy thanks to cosmological redshift (the z values the article re

> stars Galaxies. And determining the approx relative distance of distant galaxies is in fact easy thanks to cosmological redshift (the z values the article refers to). Anyway, given the number of galaxies in the ring, being at different distances but their projections just happening to form a rough circle would be even more astonishing than the galaxies in fact sharing a causal history due to some unknown early-universe mechanism. The article also mentions that either the circle or the arc in itself could be just a statistical coincidence – as long as we dok’t find more such structures – but the existence of both the circle and the arc, in the same part of the sky, is highly suspicious.

andyjohnson0 2y ago
Woops. Yes, galaxies. Too late to edit. > Anyway, given the number of galaxies in the ring, being at different distances but their projections just happening to form a rough circle would be even more astonishing than the galaxies in fact sharing a causal history due to some unknown early-universe mechanism. I don't understand what you mean by this. Why would it be "more astonishing" than an actual causal connection? Surely astronomers are more interested in causal connections than observational coincidences? To illustrate: the stars making up the constellation of Norma [1] form a rough square when seen from earth, but as their distances from Earth vary greatly this is just an illusion caused by Earth's relative orientation to them. Given the Copernican principle (which I accept is not a physical law) I'm struggling to see why a group of galaxies that form a circle only when seen from "near" earth [2] are actually cosmologically significant. I accept that the ring contains more than four galaxies, and this makes the ring more statistically significant than a square of galaxies. But it still implies a privileged viewpoint in order for it to be actually significant. I still have the gut feeling that this potential significance is more than offset by the enormously greater observational scale. tl/dr: why is this more than just naming a new constellation? (Just to re-iterate: I'm interested in understanding the errors in my mental model - and I'm not trying to poke holes in the work of scientists more qualified them me.) [1] https://en.wikipedia.org/wiki/Norma_(constellation) https://en.wikipedia.org/wiki/Norma_(constellation) [2] And also, I guess, from a similar point on the other "side" of the ring
- _xerces_ 2y ago
  I think of it in terms of degrees of freedom and statistical likelihood. If I throw a bunch of marbles on the floor and a few of them form a interesting shape that is one thing as they can only move on a plane. If I throw them in the air it is less likely to form a circle as now they are free to move in multiple directions and are not constrained to the plane. If 4 of those marbles align that is less likely than 20 of them happening to do so in a recognizable shape. 20 marbles in the air, each one being in just the right place relative to the 19 others in order to look like a circle when they can be in any position in space (vs. limited to a flat plane) is exceedingly unlikely. Even more unlikely is that an arc appears next to the ring, that would make me start to wonder if something is affecting the marbles I throw into the sky.
  - financypants 2y ago
    Is it less likely even if we can view the marbles in the air from any angle?
  - jjk166 2y ago
    But your view is a 2D projection, so you are eliminating that degree of freedom. It's equivalent to forcing them all to fall to the floor. If they form an actual ring in 3D space, that is far less probable.
- mannykannot 2y ago
  It does not seem very plausible that professional astronomers have twice made this rookie mistake and no-one has noticed yet. Furthermore, if they were just doing what amounts to drawing circles and lines on a map of galaxies, they could have discovered thousands by now!
  - mentalpiracy 2y ago
    The rate at which we are collecting data far, far outpaces the speed at which it is being analyzed. There will almost certainly be more discoveries like this as we continue surveying the cosmos with increasingly sensitive instruments.
stouset 2y ago
Looking at the angular size of the region in question, it surely would have to be that they’re equidistant from us in order to be at all interesting. There should be innumerable galaxies in and around the ring, from our perspective.
stainablesteel 2y ago
here's a picture from her presentation https://www.youtube.com/watch?v=fwRJGaIcX6A&t=173s https://www.youtube.com/watch?v=fwRJGaIcX6A&t=173s

andyjohnson0 2y ago

Woops. Yes, galaxies. Too late to edit. > Anyway, given the number of galaxies in the ring, being at different distances but their projections just happening to form a rough circle would be even more astonishing than the galaxies in fact sharing a causal history due to some unknown early-universe mechanism. I don't understand what you mean by this. Why would it be "more astonishing" than an actual causal connection? Surely astronomers are more interested in causal connections than observational coincidences? To illustrate: the stars making up the constellation of Norma [1] form a rough square when seen from earth, but as their distances from Earth vary greatly this is just an illusion caused by Earth's relative orientation to them. Given the Copernican principle (which I accept is not a physical law) I'm struggling to see why a group of galaxies that form a circle only when seen from "near" earth [2] are actually cosmologically significant. I accept that the ring contains more than four galaxies, and this makes the ring more statistically significant than a square of galaxies. But it still implies a privileged viewpoint in order for it to be actually significant. I still have the gut feeling that this potential significance is more than offset by the enormously greater observational scale. tl/dr: why is this more than just naming a new constellation? (Just to re-iterate: I'm interested in understanding the errors in my mental model - and I'm not trying to poke holes in the work of scientists more qualified them me.) [1] https://en.wikipedia.org/wiki/Norma_(constellation) https://en.wikipedia.org/wiki/Norma_(constellation) [2] And also, I guess, from a similar point on the other "side" of the ring

_xerces_ 2y ago
I think of it in terms of degrees of freedom and statistical likelihood. If I throw a bunch of marbles on the floor and a few of them form a interesting shape that is one thing as they can only move on a plane. If I throw them in the air it is less likely to form a circle as now they are free to move in multiple directions and are not constrained to the plane. If 4 of those marbles align that is less likely than 20 of them happening to do so in a recognizable shape. 20 marbles in the air, each one being in just the right place relative to the 19 others in order to look like a circle when they can be in any position in space (vs. limited to a flat plane) is exceedingly unlikely. Even more unlikely is that an arc appears next to the ring, that would make me start to wonder if something is affecting the marbles I throw into the sky.
- financypants 2y ago
  Is it less likely even if we can view the marbles in the air from any angle?
- jjk166 2y ago
  But your view is a 2D projection, so you are eliminating that degree of freedom. It's equivalent to forcing them all to fall to the floor. If they form an actual ring in 3D space, that is far less probable.
mannykannot 2y ago
It does not seem very plausible that professional astronomers have twice made this rookie mistake and no-one has noticed yet. Furthermore, if they were just doing what amounts to drawing circles and lines on a map of galaxies, they could have discovered thousands by now!
- mentalpiracy 2y ago
  The rate at which we are collecting data far, far outpaces the speed at which it is being analyzed. There will almost certainly be more discoveries like this as we continue surveying the cosmos with increasingly sensitive instruments.

stouset 2y ago

Looking at the angular size of the region in question, it surely would have to be that they’re equidistant from us in order to be at all interesting. There should be innumerable galaxies in and around the ring, from our perspective.

stainablesteel 2y ago

here's a picture from her presentation https://www.youtube.com/watch?v=fwRJGaIcX6A&t=173s https://www.youtube.com/watch?v=fwRJGaIcX6A&t=173s