Spooky Alignment of Quasars Across Billions of Light-years
eso.org
eso.org
Though I have no real idea what I'm talking about...
This feels intuitive to my mental picture of the universe.
The description of this large scale structure and the expansion of the universe has always put me in mind of watching the patterns form and reform from drips in a soapy sink or an elastic fabric being pulled apart.
In both cases, you end up with these big expanses bordered by dense stringy areas. That the motion of the stuff that snaps / shears / collapses or whatever into these strings and knots would be aligned seems perfectly logical.
Simple version: imagine you have a long pole which is spinning, fast. Then imagine a ninja comes in and slices the pole up, perpendicular to its axis, so you've got 20 short poles. The 20 short poles continue to spin on the same axis as the original long pole. If those poles are in the vacuum of space with nothing slowing them down, they will continue to spin in the same way for a very, very long time. They might wobble a bit (precession), which explains why the poles aren't all perfectly aligned in this data.
One way to test this is to ask yourself what your intuition tells you before you know the answer. You'll mostly get it wrong, unless you have formal training in the field. Intuitive "explanations" are only good after the fact, and even after the fact can be misleading and problematic, as the one you bring up here is.
The universe as a whole (very probably) has zero angular momentum. There are consequences on the large scale if this is not the case that we'd probably have detected by now. So early star formation, including quasar formation, happened in a hot zero-momentum gas cloud that filled the expanding universe. That is the structure that birthed the quasars. That means that while there may well have been local eddies, there was not any overall rotation to the gas. So why would quasars that formed in distant parts of that gas have their axes aligned in the same direction?
Short version: your mental model of the early universe is not accurate, so your intuitive explanation doesn't actually explain the phenomenon under study. Simply because it "makes sense" of the data does not make it useful. In particular, you've assumed a counter-factual.
The reason why cosmologists are surprised by these results is because they have a better understanding of the early universe, and know that there is no known mechanism to align the rotational axes of these objects. They are now wondering what that mechanism might be. Global angular momentum is one possibility, but it is far, far down on the list because it is contradicted by a lot of other data.
I do have formal training in the field, if a masters in physics counts, with a specialisation in cosmology and astrophysics.
My thesis was oriented around computational simulations of the early universe, using fluid dynamics.
This is excellent.
Relative to what? Or do you mean the observable universe relative to the CMB?
Why would you expect the ninja to do this? Why would you expect large-scale structures of the universe to form parallel to the quasars' axes?
As far as we can tell, the alignment of planetary systems in the Milky Way are random.[1]
[1] http://astronomy.stackexchange.com/questions/546/why-is-our-...
What is fascinating is that the angular momentum seems to be roughly aligned with the underlying "membranes", as if the voids themselves are actually expanding.
This was predicted so there must be some understanding of how it works. Doesn't seem that spooky.
The spookiness here is of similar nature as the spookiness how the eurasian continental plate seems to fit snugly with the american one although they are now quite far apart - i.e. we should be able to figure out which past events led to the current configuration.
I would call this result 'really cool' rather than 'spooky' but neither of those are very specific terms ;)
Do quasars that aren't parallel to their large-scale structures not have a significantly polarized signal? Maybe interference from the structure or a weaker signal because of their alignment?
This seems like it might be a breakthrough result.
the filament formation means the matter moving inward toward the virtual "centerline" (the term is used here pretty loosely obviously) of the filament. As this movement isn't perfectly aligned/balanced there is a total nonzero angular moment of the matter kind of orbiting around the "centerline" - the vector of the moment pointing along the "centerline". The bigger the object inside the filament, the more [statistically] expected its angular moment to be aligned with the total angular moment of the filament.
Now take this shape into space and make it enormously large. All of the particles in this long, stringy, tube-shaped arrangement attract each other gravitationally, so the tube starts to tighten. The particles around the outside of the tube are pulled back toward the other particles in the tube, which generally pulls them toward the centerline of the tube. Of course, each particle will have its own momentum, so if you looked down the centerline of the tube, you'd see some particles heading a little to one side of the centerline, some heading toward the other. Looking down that centerline, you'd see some particles tending to orbit around the center in a clockwise direction, some others going counter-clockwise.
It's very unlikely that there would be the same number of particles going clockwise around the centerline as counter-clockwise. Just randomly, there would very likely be somewhat more particles going one way than the other, so eventually the tightening tube would seem to be rolling around its centerline in the majority direction.
What trhway is saying is that any really big, dense clusters of particles in the tube would probably have roughly the same characteristics as the whole tube they were a part of. The particles rotating around the center of a large, dense cluster of particles in the tube would tend to resemble the rest of the tube statistically, so they would tend to roll in the same direction as the tube itself, meaning the axes of rotation of these big chunks would tend to be parallel with each other and parallel to the centerline of the tube.
yep. Just to add that as those chunks has already clumped close together they are forced to rotate much faster to preserve their share of angular momentum - thus we see rotating quasars on the background of seemingly (in our observation timescale) static filament.
(1) https://en.wikipedia.org/wiki/International_Celestial_Refere...
The team could not see the rotation axes or the jets of the quasars directly. Instead they measured the polarisation of the light from each quasar and, for 19 of them, found a significantly polarised signal.
Even if it had been the case that they were directly observing axes visible from Earth, those wouldn't appear to be parallel unless they were also proximate in the sky.
So, there might be some possibilities.
Is this a fair analogous question?
But in all seriousness, Occam's Razor is a great tool here. So far, every cosmological problem we believe we've figured out has occurred due to natural processes. There is very likely something we don't know about large scale structures (an understatement!).
* All intelligent life goes extinct before achieving interstellar colonization, or is content to remain in their home stellar system.
* We are in the first generation of life in the galaxy capable of achieving interstellar colonization, due to the time scales required for sufficient heavy elements and evolutionary complexity to arrive.
Besides, even if this was the works of some super duper advanced civilization what difference does it make? Our quest is to explore and learn new things, whether they were made by nature, God, or any freaking alien out there is irrelevant.
I've always viewed the Golden Record as a way to make humanity feel better about its future. The need to leave a legacy behind is core to who we are, and that's exactly what we did with those two discs. We left something behind that will survive for 1 billion years, with the infinitesimally small hopes that someone will find it. But, it makes us feel good.
If every quasar wherever we looked was aligned such that their axes of rotation were parallal, that would be a huge blow to the cosmological principal. Or more spookily, suppose all of the quasars studied were oriented with their poles lining up to some point in the universe. A good hint that some God created the universe for us, for example, would be for every single quasar's axis of rotation to be pointing at the earth.
But those things do not seem to be the case, and the cosmological principal appears to hold. Look at any corner of the universe, and quasars point in an arbitrary direction. Look at another corner, and they point in a different arbitrary direction. Zoom out, and now there is no cohesive direction. Homogeneity is preserved at scales much smaller than the largest structures we've observed, because the chains of quasars are themselves much smaller than the filaments and other super-structures that snake through the observable universe.
Stipulate the presence of additional universes.
Then call the whole theoretical collection a "multiverse."
Voilà. We have no reason to believe this reflects reality, but it must be assumed...
...in order to preserve the Cosmological Principle.
I know, I know. "Sufficiently large scale."
(lol)
Edit: quote from the article:
“A correlation between the orientation of quasars and the structure they belong to is an important prediction of numerical models of evolution of our Universe. Our data provide the first observational confirmation of this effect, on scales much larger that[sic] what had been observed to date for normal galaxies,” adds Dominique Sluse of the Argelander-Institut für Astronomie in Bonn, Germany and University of Liège.
So clearly this was expected.