POLARBEAR detects curls in the universe's oldest light

October 21, 2014 by Susan Brown
Measurements of polarization of the cosmic microwave background. Credit: POLARBEAR

(Phys.org) —Cosmologists have made the most sensitive and precise measurements yet of the polarization of the cosmic microwave background.

The report, published October 20 in the Astrophysical Journal, marks an early success for POLARBEAR, a collaboration of more than 70 scientists using a telescope high in Chile's Atacama desert designed to capture the universe's oldest light.

"It's a really important milestone," said Kam Arnold, the corresponding author of the report who has been working on the instrument for a decade. "We're in a new regime of more powerful, precision cosmology." Arnold is a research scientist at UC San Diego's Center for Astrophysics and Space Sciences and part of the cosmology group led by physics professor Brian Keating.

POLARBEAR measures remnant radiation from the Big Bang, which has cooled and stretched with the expansion of the universe to microwave lengths. This , the CMB, acts as an enormous backlight, illuminating the large-scale structure of the universe and carrying an imprint of .

Arnold and many others have developed sensitive instruments called bolometers to measure this light. Arrayed in the telescope, the bolometers record the direction of the light's electrical field from multiple points in the sky.

"It's a map of all these little directions that the light's electric field is pointing," Arnold explained.

POLARBEAR has now mapped these angles with resolution on a scale of about 3 arcminutes, just one-tenth the diameter of the full moon..

The team found telling twists called B-modes in the patterns of polarization, signs that this cosmic backlight has been warped by intervening structures in the universe, including such mysteries as dark matter, composed of substance that remains unknown, and the famously aloof particles called neutrinos, which elude capture making them difficult to study.

This initial report, the result of the first season of observation, maps B-modes in three small patches of sky.

Dust in our own galaxy also emits polarized radiation like the CMB and has influenced other measurements. But these patches are relatively clean, Arnold says. And variations in the CMB polarization due to dust occur on so broad a scale that they do not significantly influence the finer resolution B-modes in this report.

"We are confident that these B-modes are cosmological rather than galactic in origin," Arnold said.

Observations continue, and the data stream will ultimately be fed by additional telescopes comprising the Simons Array. Together they will map wider swaths of the sky, making fundamental discoveries possible.

"POLARBEAR is a real tour de force. With a relatively small, but strong, UC-led team we have surpassed the next-nearest competitors by an order of magnitude in sensitivity. We have paved the way towards solving the deepest mysteries in the quest to understand matter and energy at the beginning of time," said Brian Keating.

POLARBEAR is a collaboration of scientists from many institutions including experiment founder, Adrian Lee, professor of physics at UC Berkeley.

Explore further: POLARBEAR seeks cosmic answers in microwave polarization

More information: The Polarbear Collaboration: P. A. R. Ade et al. 2014 ApJ 794 171 doi:10.1088/0004-637X/794/2/171. iopscience.iop.org/0004-637X/794/2/171/

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Da Schneib
4.4 / 5 (7) Oct 21, 2014
Cool, we're identifying where the B-mode polarization comes from. Very important for interpretation of the CMB.
TimLong2001
1 / 5 (8) Oct 22, 2014
The vanishingly small photon mass (NOT zero but DEFINED as zero compared to the atomic masses) dictates a loss of photon energy over time, resulting in a red shift. THE CMBR would be the resultant interference frequency of all radiation in space and varies slightly from place to place. Georges Lemaitre, a priest/physicist, proposed a theologically consistent explanation that was promoted by Milton LaSalle Humason (Hubble's muleskinner, janitor, assistant at the Mt. Wilson Observatory) but Hubble did not interpret the red shift as a Doppler shift due to expansion, until quite later in life, presumably due to the influence of Humason and others.
Protoplasmix
5 / 5 (10) Oct 22, 2014
Following quotes are from http://bolo.berke...ed/31114 which has a link to the paper at arXiv there.

"The measurement rejects the possibility of zero B-mode power from gravitational lensing at 97.5% confidence ...This announcement came one week before the BICEP2 team announced their detection of B-mode power at degree scales, consistent with an energy scale for cosmic inflation of about 10^16 GeV … These remarkable results add to the compelling science case for precision characterization of the CMB B-mode angular power spectrum … This [continued observation and instrument upgrades] provides the opportunity to probe the physics of neutrinos and dark energy, and also allows the removal of the lensing "foreground" signal to enable the precision characterization of the primordial inflationary B-mode signal."

Where's the science-bashing troll patrol? Especially the guy who has been cautioning everyone on the BICEP2 'debacle'.
tritace
Oct 22, 2014
This comment has been removed by a moderator.
tritace
Oct 22, 2014
This comment has been removed by a moderator.
Da Schneib
4.3 / 5 (6) Oct 22, 2014
Ummmm, why would gravitational waves have to be formed before inflation, rather than during inflation?
tritace
Oct 22, 2014
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Da Schneib
4.6 / 5 (10) Oct 22, 2014
Because the inflation was supposed to be pretty fast, non-causual or chaotic at least.
That doesn't make any sense; it's a non-sequitur, because the speed of the inflation is what *caused* the gravitational waves.

You appear to be claiming that gravitational waves come from nothing, or that reputable scientists have said so. This is at best incorrect.
saposjoint
4.1 / 5 (9) Oct 22, 2014
Is that Zephir with a new sock?
Da Schneib
4.3 / 5 (6) Oct 22, 2014
Might be. We'll have to see if it mentions AWT. :D
tritace
Oct 22, 2014
This comment has been removed by a moderator.
Da Schneib
4.5 / 5 (8) Oct 22, 2014
LOL, nice catch, sapo!
NOM
4.6 / 5 (10) Oct 22, 2014
Is that Zephir with a new sock?
I bet you to that guess by two days :P

http://phys.org/n...tum.html
tritace
Oct 22, 2014
This comment has been removed by a moderator.
tritace
Oct 22, 2014
This comment has been removed by a moderator.
Da Schneib
4.6 / 5 (9) Oct 22, 2014
Ummmm, I've seen your definition of "nothing" before, Zeph, and it was wrong then and is still wrong now.

And it's not mainstream physics, it's mainstream cosmology.

Inflation was introduced because it explains the flatness and homogeneity of the universe, and explains the lack of magnetic monopoles.

Emergence from nothing was an unexpected benefit of the Cosmic Inflation Theory of the Big Bang Theory; it was not foreseen when inflation was originally proposed by Guth. Vilenkin was the one who put "creation from nothing" on a firm mathematical basis, and linked it to the inflationary theory, although I don't believe he was the originator of the idea IIRC. I'd have to look it up.

On edit: I checked up on it and it may have been Andrei Linde who did the math for the "universe from nothing" proposal made earlier. I'd have to poke further to find out who originally proposed it.
tritace
Oct 22, 2014
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Da Schneib
4.5 / 5 (8) Oct 22, 2014
No, Zeph, you're not explaining anything at all. You've mentioned this "tilt" thing before and got pwnt, right along with rc.

Just like AWT.

Furthermore, noted that you have no explanation of the horizon, flatness, or monopole problems.
tritace
Oct 22, 2014
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tritace
Oct 22, 2014
This comment has been removed by a moderator.
NOM
4.6 / 5 (11) Oct 22, 2014
I wonder if physorg needs a "this one's a Zeph" button next to the Report.
saposjoint
4.1 / 5 (9) Oct 22, 2014
Damned straight. I'm actually wondering if Farsight would like to have Zephir's babies, or vice versa.

Wow.
Bob Osaka
1 / 5 (6) Oct 23, 2014
Yo @protoplasmix 'll be your huckleberry. Has BICEP2 been vindicated for the announcement of the discovery of direct observation of gravitational waves? Really? It was a debacle. Got dust in your eyes yet, still?
Kind of concerned about Polarbear too. Shameless self-promotion there at the end. Nice to know they have their bolometer working, when the results are independently verified outside of the Atacama desert then, maybe we'll have something. This initial report is no reason to dress Nobel laureates in penguin-like tuxedos then set a polar bear loose in Antarctica.
If one were mistaken by 2.5% over a distance of a trillion,trillion,trillion,trillion approximately kilometers, how far off could one be?
More sensitive instrumentation, less sensitive physicists.
Da Schneib
3.7 / 5 (3) Oct 23, 2014
you're not explaining anything at all
It's not rocket science: the inflation blows up the primordial fluctuations, so that they appear bigger.
It does that just as well if they appear *during* inflation as *before* it. In fact, because the expansion is exponential, the later they appear the *bigger* they will be.

You're right, it's not rocket science.
Da Schneib
4.3 / 5 (6) Oct 23, 2014
I wonder if physorg needs a "this one's a Zeph" button next to the Report.
Honestly LOL. Even when I should be being quiet. :D

Damned straight. I'm actually wondering if Farsight would like to have Zephir's babies, or vice versa.
/me has nightmares over this. Do you suppose it might just cancel out and they'd be flat-earthers?

Wow.
Yeah. Just wow.
IMP-9
4.3 / 5 (12) Oct 23, 2014
The gravitational lensing of what? The gravitational lensing of galaxies or gravitational lensing of dark matter between them? Both they were formed well after alleged Big Bang and inflation.


This is not BICEP, they are not attempting to detect primordial B modes. The lensing they are interested in is late time, nothing to do with inflation or gravitational waves. There is no need to subtract the lensing, it itself is a power cosmological probe.

Someone else asked what this experiment has over BICEP, the answer is frequency. This experiment has multiple bands to do foreground subtraction itself.
erson
Oct 23, 2014
This comment has been removed by a moderator.
Uncle Ira
2.3 / 5 (3) Oct 23, 2014
Yeah they are
IMP-9
4.2 / 5 (10) Oct 23, 2014
Please read my comment again, I'll help you.

they are not attempting to detect PRIMORDIAL B modes


Lensing B modes are not primordial, they are late time. This paper is on smaller scales than BICEP, higher moments where lensing dominates.

As they say in their paper.

On these angular scales, gravitational lensing of the CMB by intervening structure in the universe is expected to be the dominant source of B-mode polarization.


They even define their terms.

Any primordial B-modes would be evidence for tensor or vector perturbations in the gravitational metric when the CMB was emitted.


Obviously lensing does not fall into this category, hence it is not primordial.

Well done, you didn't read the paper or my comment and called me an imbecile.
Uncle Ira
4.3 / 5 (6) Oct 23, 2014
Well done, you didn't read the paper or my comment and called me an imbecile.


IMP-Skippy. I am sorry about my "yeah they are" comment. I was trying to be a smarty alex with Zepher-Skippy who wrote that imbecile thing. Sometimes I don't say things too good me.

I really think you are one of the smart-Skippys on here, so I am sorry about making it look like I was agreeing with Zepher-Skippy.
erson
Oct 23, 2014
This comment has been removed by a moderator.
IMP-9
4.1 / 5 (9) Oct 23, 2014
This is your ad-hoced claim.


No, I provided a quote to prove it. You clearly haven't read the paper. For example:

... lensing B-modes are not contaminated by large primordial CMB fluctuations


Lensing comes from large scale structure, which is explicitly late time. This paper is not about primordial B modes.

as they're both focused to fluctuations at small angular scales


Primordial B modes are larger scales than lensing.

tritace
Oct 23, 2014
This comment has been removed by a moderator.
IMP-9
4.1 / 5 (9) Oct 23, 2014
But they can still be contaminated with these smaller ones?


Lensing modes are the small scale modes. They do not contaminate themselves.

the POLARBEAR cannot confirm the BICEP2 results


No. We're talking about this paper. This paper is about smaller scales than BICEP.
Protoplasmix
5 / 5 (4) Oct 25, 2014
@protoplasmix Has BICEP2 been vindicated for the announcement of the discovery of direct observation of gravitational waves? Really? It was a debacle. Got dust in your eyes yet, still?

Uh, Zeph wasn't the guy I had in mind when I voiced objection to the characterization of science-in-progress as a 'debacle'. And he quickly referred to it as a 'debate', and later even said the work is at a 'third mental level' beyond what a novice can fully grasp or appreciate.

As for dust, read the POLARBEAR paper. In the intro they say:
The small amplitude of this signal compared to other sources of anisotropy in the CMB makes it very difficult to measure without contamination from the instrument or astrophysical foregrounds.
Re: foreground they've accounted for galactic dust, galactic synchrotron, radio galaxies, and dusty galaxies.

As for GWs, the work is cutting-edge science and the results will be exciting either way.
swordsman
not rated yet Oct 27, 2014
All electromagnetic radiation curves. It is a matter of how you measure it.

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