Cold cosmic mystery solved: Largest known structure in the universe leaves its imprint on CMB radiation

April 20, 2015
The Cold Spot area resides in the constellation Eridanus in the southern galactic hemisphere. The insets show the environment of this anomalous patch of the sky as mapped by Szapudi's team using PS1 and WISE data and as observed in the cosmic microwave background temperature data taken by the Planck satellite. The angular diameter of the vast supervoid aligned with the Cold Spot, which exceeds 30 degrees, is marked by the white circles. Credit: ESA Planck Collaboration

In 2004, astronomers examining a map of the radiation leftover from the Big Bang (the cosmic microwave background, or CMB) discovered the Cold Spot, a larger-than-expected unusually cold area of the sky. The physics surrounding the Big Bang theory predicts warmer and cooler spots of various sizes in the infant universe, but a spot this large and this cold was unexpected.

Now, a team of astronomers led by Dr. Istvan Szapudi of the Institute for Astronomy at the University of Hawaii at Manoa may have found an explanation for the existence of the Cold Spot, which Szapudi says may be "the largest individual structure ever identified by humanity."

If the Cold Spot originated from the Big Bang itself, it could be a rare sign of exotic physics that the standard cosmology (basically, the Big Bang theory and related physics) does not explain. If, however, it is caused by a foreground structure between us and the CMB, it would be a sign that there is an extremely rare large-scale structure in the mass distribution of the universe.

Using data from Hawaii's Pan-STARRS1 (PS1) telescope located on Haleakala, Maui, and NASA's Wide Field Survey Explorer (WISE) satellite, Szapudi's team discovered a large supervoid, a vast region 1.8 billion light-years across, in which the density of galaxies is much lower than usual in the known universe. This void was found by combining observations taken by PS1 at optical wavelengths with observations taken by WISE at infrared wavelengths to estimate the distance to and position of each galaxy in that part of the sky.

Earlier studies, also done in Hawaii, observed a much smaller area in the direction of the Cold Spot, but they could establish only that no very distant structure is in that part of the sky. Paradoxically, identifying nearby large structures is harder than finding distant ones, since we must map larger portions of the sky to see the closer structures. The large three-dimensional sky maps created from PS1 and WISE by Dr. András Kovács (Eötvös Loránd University, Budapest, Hungary) were thus essential for this study. The supervoid is only about 3 billion light-years away from us, a relatively short distance in the cosmic scheme of things.

Imagine there is a huge void with very little matter between you (the observer) and the CMB. Now think of the void as a hill. As the light enters the void, it must climb this hill. If the universe were not undergoing accelerating expansion, then the void would not evolve significantly, and light would descend the hill and regain the energy it lost as it exits the void. But with the accelerating expansion, the hill is measurably stretched as the light is traveling over it. By the time the light descends the hill, the hill has gotten flatter than when the light entered, so the light cannot pick up all the energy it lost upon entering the void. The light exits the void with less energy, and therefore at a longer wavelength, which corresponds to a colder temperature.

Getting through a supervoid can take millions of years, even at the speed of , so this measurable effect, known as the Integrated Sachs-Wolfe (ISW) effect, might provide the first explanation one of the most significant anomalies found to date in the CMB, first by a NASA satellite called the Wilkinson Microwave Anisotropy Probe (WMAP), and more recently, by Planck, a satellite launched by the European Space Agency.

While the existence of the supervoid and its expected effect on the CMB do not fully explain the Cold Spot, it is very unlikely that the supervoid and the Cold Spot at the same location are a coincidence. The team will continue its work using improved data from PS1 and from the Dark Energy Survey being conducted with a telescope in Chile to study the Cold Spot and supervoid, as well as another large void located near the constellation Draco.

The study is being published online on April 20 in Monthly Notices of the Royal Astronomical Society by the Oxford University Press. In addition to Szapudi and Kovács, researchers who contributed to this study include UH Manoa alumnus Benjamin Granett (now at the National Institute for Astrophysics, Italy), Zsolt Frei (Eötvös Loránd), and Joseph Silk (Johns Hopkins).

Explore further: Baby universe picture brought closer to theory

More information: Detection of a supervoid aligned with the cold spot of the cosmic microwave background, mnras.oxfordjournals.org/content/450/1/288.full

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vlaaing peerd
4.2 / 5 (5) Apr 20, 2015
I must be mistaken, but what map is actually shown up there? Seems our neighbour galaxy Andromeda is a gazillion lightyears away from the moon (??)
Mumra
5 / 5 (7) Apr 20, 2015
I'd guess that its trying to show the angular size of the cold spot relative to known objects.
wasp171
4 / 5 (4) Apr 20, 2015
SO how present cosmological assumptions on homogeneity and isotropy deal with that?
antialias_physorg
5 / 5 (13) Apr 20, 2015
I must be mistaken, but what map is actually shown up there? Seems our neighbour galaxy Andromeda is a gazillion lightyears away from the moon (??)

The map is a view as seen from Earth (Mollweid projection). Distances between two points on the map are not indicative of their real distances in light years. (Note that the part where we see the milky way in the sky streatches the entire breadth of the map)

SO how present cosmological assumptions on homogeneity and isotropy deal with that?

Maybe you missed this part of the article:
If the Cold Spot originated from the Big Bang itself, it could be a rare sign of exotic physics that the standard cosmology (basically, the Big Bang theory and related physics) does not explain.
...but it looks like it's rather an artifact due to a large scale structure (so, unfortunately, probably no new physics here)
IMP-9
5 / 5 (11) Apr 20, 2015
Mumra is quite right. It's an attempt to show the scale of the map, the Moon isn't actually observed at any time by Planck.

SO how present cosmological assumptions on homogeneity and isotropy deal with that?


A 200 Mpc 20% void is a significant fluctuation for the standard model but not unexpected, you expect about a dozen such voids across the whole sky and voids of this scale are known in SDSS. The standard model only described homogeneity and isotropy as a limit at large scales, it doesn't claim either is absolute.
Tuxford
1 / 5 (8) Apr 20, 2015
In SubQuantum Kinectis blue shifting occurs in the relative presence of matter (such as inside our galaxy), and red shifting occurs in the absence of matter. So, in the direction of the void region, a little extra red shifting would occur, leading to a loss of energy observed as a lower temperature.
Torbjorn_Larsson_OM
5 / 5 (9) Apr 20, 2015
I guess I have to nitpick the title, if "solved" actually means 'a good lead for eventually making a full prediction' ("... do not fully explain the Cold Spot [however] it is very unlikely that the supervoid and the Cold Spot at the same location are a coincidence.")

But, yeah: yay! Every since the statistics of the area's edge transition was shown to be wrong for just about anything but a void, this was to be expected I guess. [Ref would be a paper on arxiv, but I don't seem to have saved its title.]

Planck 2014 seems to have resolved their tension with WMAP (which seems to have mainly been noise from a 4K cooler line), and then the significance of candidates for anomalies went down.

And now the set of those anomaly candidates that were still reasonable have been abruptly halved. That bucket had to be emptied out, and now there is very little left that would segue into tensions with other observations or obvious hints at new physics.
Torbjorn_Larsson_OM
5 / 5 (9) Apr 20, 2015
I found the paper on arxiv. [ http://arxiv.org/...66v2.pdf ]

Actually the void can be solved. The predict a 20 uK deficit but the observation is 170 uK. However, that is a linear prediction, the void size is uncertain, relativistic effects should be accounted for, et cetera.

On the other hand it is not an anomaly candidate, it is an anomaly, a 3.3 sigma fluctuation of a whole-sky Gaussian, at its currently estimated size (if I understand it correctly). That is roughly 1/400 observable universes that would have it. On the other hand they look for hot and cold spots, high and low peaks in the CMB, correlations between peaks, correlation between peaks and directions, tensions in parameters, et cetera et cetera. Data fishing of some 100 possibilities (say) would mean that they would see some anomaly in 1 out of 4 universes...
rufusgwarren
3 / 5 (4) Apr 20, 2015
So how much is the wavelength stretched? Not sure the above reasoning makes much sense. if we are part of a matter stream and accelerating from front to back, this could well be the rear. This would make more sense than the unknown! What if there is no unknown or "new physics", only misguidance in measurement.
rufusgwarren
2.8 / 5 (9) Apr 20, 2015
The big bang is not fact but simply a theory. GR is a theory and not fact in spite of attempts at proof. Logically, neither can be proven. We are very, very stupid. We see red and call it empty space, somewhat nonsensical. in fact, there should exist that which we cannot see without the use of GR or BB, only logic and sound physics well enable vision. Nor do we have intelligence upon the planet to see our mistakes. Only guesses at the unexplained due to a false physics as our "measuring stick" since the 20th century accepted nonsense.
skills4u
3 / 5 (1) Apr 20, 2015
Anyone else scratching their head over [quote] Now think of the void as a hill. As the light enters the void, it must climb this hill. If the universe were not undergoing accelerating expansion, then the void would not evolve significantly, and light would descend the hill and regain the energy it lost as it exits the void. But with the accelerating expansion, the hill is measurably stretched as the light is traveling over it. By the time the light descends the hill, the hill has gotten flatter than when the light entered, so the light cannot pick up all the energy it lost upon entering the void. The light exits the void with less energy, and therefore at a longer wavelength, which corresponds to a colder temperature. [/quote]
loose and regain energy ?
Why would light going through a void loose energy ? It seems logical to me that light traveling through less mass (the void) would actually increase its speed without any loose of energy.

Can anyone expound on this for me ?
Da Schneib
5 / 5 (2) Apr 20, 2015
Because of gravitational attraction from the matter outside the void.
EnsignFlandry
4.1 / 5 (9) Apr 20, 2015
The big bang is not fact but simply a theory. GR is a theory and not fact in spite of attempts at proof. Logically, neither can be proven. We are very, very stupid. We see red and call it empty space, somewhat nonsensical. in fact, there should exist that which we cannot see without the use of GR or BB, only logic and sound physics well enable vision. Nor do we have intelligence upon the planet to see our mistakes. Only guesses at the unexplained due to a false physics as our "measuring stick" since the 20th century accepted nonsense.


You do not realize what the word "theory" means in science. GR has been verified, and the BB too. Perhaps you can send in a paper showing our false physics and the correct one only you know about. The rest of your post is nonsense.
SuperThunderRocketJockey
3 / 5 (2) Apr 21, 2015
Whoa, that's huge. WHOA, that's close! "Huge, close, and unknown," the most comforting words in space-English. Now, I'm not saying we should worship it yet, but if it starts moving towards us, I stand ready to hear voices and do its bidding... er..., for science?

If you walk into a forest you can only get halfway before you're walking out of the forest again, because over halfway is over halfway through the forest. If the forest floor is expanding in all directions as you take this journey, the walk halfway out will take longer (thus more energy) than the walk halfway in, because the expansion adds up and you wasted a lot of time walking halfway in. At least that's what the Great Cosmic Void Structure told me before it commanded me to not eat sugar on Thursday. I am so going to commit heresy on that one.
Mike_Massen
3.5 / 5 (8) Apr 21, 2015
rufusgwarren without understanding basis of Science claimed
GR is a theory and not fact in spite of attempts at proof
Before you consider barking off rubbish and badly articulated jibes you should not look so stupid be FIRST getting an essential education in the basics:-

https://en.wikipe...c_theory

GR (& SR) has been experimentally verified. Correct GPS functionality relies on its correction several times each day !
https://en.wikipe...g_System

The first well designed experiment for GR & SR detailed here:-
https://en.wikipe...periment

So PLEASE get an education in basics of Physics & understand the training & education necessary to craft experiments that converge towards a definitive outcome.

Eg.
https://en.wikipe...eriments

I see another reply to you also, so YES please tell us of your theory & method to craft an experiment to prove it ?
docile
Apr 21, 2015
This comment has been removed by a moderator.
rossim22
2.3 / 5 (6) Apr 21, 2015
rufusgwarren without understanding basis of Science claimed
GR is a theory and not fact in spite of attempts at proof
Before you consider barking off rubbish and badly articulated jibes you should not look so stupid be FIRST getting an essential education in the basics:-

https://en.wikipe...c_theory


If you state BB or GR as 'confirmed' or 'verified' then you are not a scientist, or remain unaware of scientific philosophy. GPS can be explained using GR, yes. But you are dismissing the possibility of any other conceivable mechanism to produce the same results we observe. Redshift is another excellent example. It could be caused by recessional velocity, that argument holds water. But you are ignoring the possibility that any other conceivable mechanism could be producing the same observations from our perspective. GR cannot be falsified in any way, its just a story which cannot be proved wrong and doesn't represent reality.
skills4u
3 / 5 (1) Apr 21, 2015
Because of gravitational attraction from the matter outside the void.


I hope that was not a reply to my question as it makes no sense... I can see gravitational pull having an effect, but it effects it both ways, as light is heading through the void it is being pulled one way, but once it passes that matter it will be pulled in the opposite direction. I must contemplate this further....
Da Schneib
5 / 5 (3) Apr 21, 2015
You do not realize what the word "theory" means in science. GR has been verified, and the BB too.
The theory in science can be only falsified, never confirmed.
Actually that's incorrect. You've forgotten consilience, in which data from a completely different field of investigation shows that a theory is correct. There are many examples of it, and many examples in which a theory in one field is supported and extended by data and observations from more than one other field.

When things fit together that well it's cranky to deny them, and GR is one of those kinds of things.

BTW The epicyclic theory has been verified too.
BS. Quote and link please.

The science wannabes will never learn from their mistakes, until there is some at least residual opportunity for to make money with existing theories.
Lotsa people making lotsa money. For example Thomas Edison. Let's start there.
Da Schneib
5 / 5 (1) Apr 21, 2015
Because of gravitational attraction from the matter outside the void.
I hope that was not a reply to my question as it makes no sense...
Actually, it does. When radiation enters a void, it is retarded (in the case of light, redshifted) all the way to the center of the void, or as close as it approaches it, by the gravity of the matter outside the void, and then it's blueshifted all the way out from that point, regaining the energy it lost on the way in. But, if the void has gotten bigger during the first half of the journey, then it can't regain all the energy on the way out, so it winds up with a net redshift- i.e., cooler.

It's really simple if you know basic physics.

I can see gravitational pull having an effect, but it effects it both ways, as light is heading through the void it is being pulled one way, but once it passes that matter it will be pulled in the opposite direction. I must contemplate this further....
Remember the void got bigger.
sandler
not rated yet Apr 21, 2015
The microwave background radiation stems from Big Bang theory but how would it be explained by alternatively "high" models? In a Universe where every physical thing is moving and spinning, having constant background of radiation is unwarranted. It does remind however of EMF field/radiation observed near powerlines or microwaves which is constant. It would also relate to the mysterious alignment of Quasar Galaxies:

http://www.eso.or...eso1438/

Since we do know there is superconducting current vortex in Earth core which is responsible for it's magnetic field, it could induce another current in nearby conductor and create a polarized EMF between them, whose spin itself could be a factor of it, as in electrical motor. Because gravity moves them in constant orbits, their fields could add up to cause small temperature increase and create CMBs and cold spots over light years.
Mike_Massen
3.7 / 5 (3) Apr 22, 2015
docile has a problem with this claim
The theory in science can be only falsified, never confirmed
So when corrections for GPS must be added and are done so in accordance with GR & SR calculations and work, then what does this tell you about Relativity, is it not "some" confirmation - even a little ?

docile offered
BTW The epicyclic theory has been verified too
Since you refer to this, a specific link please, I do not wish to get random rubbish via google far more efficient if you offer a link, you have plenty of space to do so and thus converge & not just argue ?

docile claimed
The science wannabes will never learn from their mistakes, until there is some at least residual opportunity for to make money with existing theories.
Who are these 'wannabes', did you meet them at high school or university when you passed various physics courses ?

What sort of mathematics suggests GR/SR is wrong and falsifiable, I am not sure of your position ?
skills4u
5 / 5 (2) Apr 22, 2015
Da Schneib, Thanks for your reply. I was contemplating this last night as I was trying to fall asleep and realized I was not thinking of gravity as a well which explains their uphill/downhill analogy.

It's really simple if you know basic physics


I have never had a physics class but I do like reading about it and asking questions.

Da Schneib
5 / 5 (2) Apr 22, 2015
Keep on readin', skills! And keep on askin', because that's the only way to get answers. ;)

Do you know Newton's three laws of motion, and his law of universal gravitation? Those would be where to start. Then you can tack relativity on top of that and be pretty aware of how these things work.

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