first direct evidence of cosmic inflation in gravational wav

[dragon]

Scientists have found the first direct evidence of cosmic inflation in gravitational waves from the Big Bang detected in the cosmic microwave background radiation of our universe.

The major announcement came from the Harvard-Smithsonian Center for Astrophysics. Here's the technical data and papers that go along with the announcement from the group at the Bicep (Background Imaging of Cosmic Extragalactic Polarization) project.

Researchers will be giving a press conference, streamed live starting at 11:55 a.m. EDT at this link ;and this back up link, though neither are working for us right now. From twitter, it's looking like they've started the press conference early, though we can't confirm that.

As the rumors have been saying, the discovery has to do with finding of evidence of primordial gravitational waves, ripples in the fabric of spacetime that were produced in the early universe. The imprint they left when the universe was born 13.82 billion years ago would give us an idea of what the universe was like when it just came into existence.

A press release from NASA says:

Astronomers are announcing today that they have acquired the first direct evidence that gravitational waves rippled through our infant universe during an explosive period of growth called inflation. This is the strongest confirmation yet of cosmic inflation theories, which say the universe expanded by 100 trillion trillion times, in less than the blink of an eye.

Here's the kind of data they are working with, this image of the cosmic microwave background radiation from Plank:

According to The Guardian: "The signal is rumored to have been found by a specialized telescope called Bicep (Background Imaging of Cosmic Extragalactic Polarization) at the south pole."

Gravitational waves were the last untested prediction of Albert Einstein’s General Theory of Relativity. The BICEP researchers were analyzing data from the early universe to find the signals of these waves. According to cosmologists on twitter, the result was significant.

"It's been called the Holy Grail of cosmology," Hiranya Peiris, a cosmologist from University College London, told The Guardian. "It would be a real major, major, major discovery."

There are still reasons not to get ahead of ourselves. This new data will need to be scrutinized by other scientists and confirmed by other experiments.

link

[Guardsman Bass]

I'd been hearing about that in the news, but it's good to know that they found it for sure.

[Borgholio]

I'd say this news is making waves.

[dragon]

more detailed info

Researchers believe they have found the signal left in the sky by the super-rapid expansion of space that must have occurred just fractions of a second after everything came into being.

It takes the form of a distinctive twist in the oldest light detectable with telescopes.

The work will be scrutinised carefully, but already there is talk of a Nobel.

"This is spectacular," commented Prof Marc Kamionkowski, from Johns Hopkins University.
Continue reading the main story
“Start Quote

Nature did not have to be so kind and the theory didn't have to be right”

Prof Alan Guth Inflation pioneer

"I've seen the research; the arguments are persuasive, and the scientists involved are among the most careful and conservative people I know," he told BBC News.

The breakthrough was announced by an American team working on a project known as BICEP2.

This has been using a telescope at the South Pole to make detailed observations of a small patch of sky.

The aim has been to try to find a residual marker for "inflation" - the idea that the cosmos experienced an exponential growth spurt in its first trillionth, of a trillionth of a trillionth of a second.
BICEP data Gravitational waves from inflation put a distinctive twist pattern in the polarisation of the CMB

Theory holds that this would have taken the infant Universe from something unimaginably small to something about the size of a marble. Space has continued to expand for the nearly 14 billion years since.

Inflation was first proposed in the early 1980s to explain some aspects of Big Bang Theory that appeared to not quite add up, such as why deep space looks broadly the same on all sides of the sky. The contention was that a very rapid expansion early on could have smoothed out any unevenness.

But inflation came with a very specific prediction - that it would be associated with waves of gravitational energy, and that these ripples in the fabric of space would leave an indelible mark on the oldest light in the sky - the famous Cosmic Microwave Background.

The BICEP2 team says it has now identified that signal. Scientists call it B-mode polarisation. It is a characteristic twist in the directional properties of the CMB. Only the gravitational waves moving through the Universe in its inflationary phase could have produced such a marker. It is a true "smoking gun".

Speaking at the press conference to announce the results, Prof John Kovac of the Harvard-Smithsonian Center for Astrophysics, and a leader of the BICEP2 collaboration, said: "This is opening a window on what we believe to be a new regime of physics - the physics of what happened in the first unbelievably tiny fraction of a second in the Universe."
Completely astounded

The signal is reported to be quite a bit stronger than many scientists had dared hope. This simplifies matters, say experts. It means the more exotic models for how inflation worked are no longer tenable.

The results also constrain the energies involved - at 10,000 trillion gigaelectronvolts. This is consistent with ideas for what is termed Grand Unified Theory, the realm where particle physicists believe three of the four fundamental forces in nature can be tied together.

But by associating gravitational waves with an epoch when quantum effects were so dominant, scientists are improving their prospects of one day pulling the fourth force - gravity itself - into a Theory of Everything.

The sensational nature of the discovery means the BICEP2 data will be subjected to intense peer review.

It is possible for the interaction of CMB light with dust in our galaxy to produce a similar effect, but the BICEP2 group says it has carefully checked its data over the past three years to rule out such a possibility.

Other experiments will now race to try to replicate the findings. If they can, a Nobel Prize seems assured for this field of research.

Who this would go to is difficult to say, but leading figures on the BICEP2 project and the people who first formulated inflationary theory would be in the running.

One of those pioneers, Prof Alan Guth from the Massachusetts Institute of Technology, told the BBC: "I have been completely astounded. I never believed when we started that anybody would ever measure the non-uniformities of the CMB, let alone the polarisation, which is now what we are seeing.

"I think it is absolutely amazing that it can be measured and also absolutely amazing that it can agree so well with inflation and also the simplest models of inflation - nature did not have to be so kind and the theory didn't have to be right."

British scientist Dr Jo Dunkley, who has been searching through data from the European Planck space telescope for a B-mode signal, commented: "I can't tell you how exciting this is. Inflation sounds like a crazy idea, but everything that is important, everything we see today - the galaxies, the stars, the planets - was imprinted at that moment, in less than a trillionth of a second. If this is confirmed, it's huge.

"
link

[Steel]

Fascinating. I remember inflation was the big thing that all the astrophysics people were interested in when I was doing my masters. Fascinating that it works so well with the simple models and fits with all the other stuff, seems too good to be true.

Now the big question will be* what drove inflation? Why did it happen?

*aside from if someone confused their simulated reference dataset with the real data

[Eternal_Freedom]

Now the big question will be* what drove inflation? Why did it happen?

*aside from if someone confused their simulated reference dataset with the real data

[physics snark]I've no idea what the new idea will be, but in best science tradition, we'll take an existing concept and add "dark" to the front. It worked so well for matter and energy after all [/physics snark]

Seriously though this is really cool stuff. As for what drove it, I suspect dark energy will be involved, since that's what is believed to be driving the current acceleration of expanding spacetime.

[Sea Skimmer]

I hope they can find this in the existing data from Planck as well, because that satellite is now dead and we don't as far as I can tell have any other telescope projects coming up for this as confirmation sources.

[Ziggy Stardust]

So … what exactly is the evidence? These papers are exceptionally vague, unless I missed something. All it says is that they discovered "a characteristic twist in the directional properties of the CMB."

But what exactly did they discover and why is it such strong evidence of cosmic inflation?

[Ariphaos]

Large-scale patterns in the polarization of CMB light, I believe.

[phongn]

I hope they can find this in the existing data from Planck as well, because that satellite is now dead and we don't as far as I can tell have any other telescope projects coming up for this as confirmation sources.

There are quite a few B-mode projects so corroboration (or contradiction) shouldn't be far behind.

But what exactly did they discover and why is it such strong evidence of cosmic inflation?

The theory of inflation predicts that there should be b-mode polarization in the cosmic microwave background.

[jwl]

IT WAS fun while it lasted. Last March, cosmologists celebrated what seemed like evidence that space-time had shaken violently during the big bang. The discovery of the apparent gravitational waves was hailed as the "smoking gun" for a theory that the infant universe experienced an epic growth spurt known as inflation. Physicists popped corks in elation and dreamed of a Nobel prize.

But 11 months later, this smoking gun has itself gone up in smoke, and researchers are nursing a hangover. "We are pretty much back to where we were before," says Alan Guth of the Massachusetts Institute of Technology, who proposed the theory of inflation in 1981.

It all started on 17 March, when astronomers using a telescope called BICEP2 at the South Pole reported seeing telltale signs of gravitational waves in a tiny patch of sky viewed at a particular wavelength in the microwave range. That was exciting because although inflation should have produced gravitational waves, there was no guarantee they would be strong enough to detect. There are hundreds of models of inflation, each with its own prediction about how fast the universe expanded – and therefore how powerful the resulting gravitational waves would be.

So it was even more astounding that the strength of BICEP2's waves fitted the simplest version. In this model, inflation proceeded more or less like a ball rolling down the inside of a U-shaped bowl, with expansion starting fast then slowing down. "The simplest theory yields predicted gravitational waves right where BICEP2 seemed to see them," says John Peacock at the University of Edinburgh in the UK.

But the excitement was short-lived. A series of studies soon suggested that dust within our galaxy may have muddied the picture. Observations at other wavelengths were needed to clear up the confusion, as dust shines more brightly at certain wavelengths than at others.

In September, researchers used Europe's Planck satellite to show that BICEP2's entire signal could be due to dust (Astronomy & Astrophysics, doi.org/zt8). The final nail in the coffin came last week, when a study combining BICEP2 and Planck data showed that the dust observed with Planck lined up with the signal the BICEP2 team had attributed to gravitational waves. This all but rules out the simplest model: if they are out there, any gravitational waves from inflation must have been no more than about half as strong as those seen with BICEP2, in line with the Planck team's earlier estimates.

Upcoming observations will put more models to the test by improving measurements of possible contaminants. That means studying the sky with great sensitivity at a range of places and microwave wavelengths. "To claim a detection of a primordial signal, one has to exclude the possibility, to the fullest extent possible, that something else hasn't generated the signal," says William Jones of Princeton University, who leads a balloon-borne mission called SPIDER that is expected to release its observations in a year or so.

Gravitational waves are not inflation's only prediction. For example, ultra-fast expansion can explain how the universe, which could have started out with any curvature, came to appear so flat. But a rival theory, which says the universe cycles between periods of expansion and contraction, can also account for those mysteries, says Paul Steinhardt of Princeton, a pioneer of both inflation and its cyclic competitor.

The cyclic model predicts that we should not see any gravitational waves from the early universe, so BICEP2's initial announcement seemed to deal it a fatal blow. Now, without a discovery of gravitational waves, the theory of inflation has lost its most powerful line of evidence. "The current non-detection certainly does not rule inflation out, but equally, without a detection, many, including me, would not consider the theory to be proved true," says Peacock.

Steinhardt fears that inflation is so flexible it cannot be proved false. Once started, inflation is hard to stop, and should have spawned a zoo of universes, each with different properties. "Any result can fit somewhere in the multiverse," Steinhardt says. Inflation's simplest model barely fits the observations now, leaving only more complicated models still alive, he adds. "Shouldn't that give some people pause?"

"It worries me," admits Matias Zaldarriaga of the Institute for Advanced Study in Princeton, who helped figure out how to spot signs of gravitational waves nearly 20 years ago. But he adds: "Nature is how it wants to be. It doesn't follow from any logic that the simpler thing is the true one."

This article appeared in print under the headline "Big bang discovery crumbles to dust"

http://www.newscientist.com/article/mg2 ... smoke.html
Most recent paper on it:

We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400 deg2 patch of sky centered on RA 0h, Dec. −57.5◦. The combined maps reach a depth of 57 nK deg in Stokes Q and U in a band centered at 150 GHz. Planck has observed the full sky in polarization at seven frequencies from
30 to 353 GHz, but much less deeply in any given region (1.2 µK deg in Q and U at 143 GHz). We detect 150×353 cross-correlation in B-modes at high significance. We fit the single- and crossfrequency power spectra at frequencies above 150 GHz to a lensed-ΛCDM model that includes dust and a possible contribution from inflationary gravitational waves (as parameterized by the tensor-toscalar ratio r). We probe various model variations and extensions, including adding a synchrotron component in combination with lower frequency data, and find that these make little difference to the r constraint. Finally we present an alternative analysis which is similar to a map-based cleaning of the dust contribution, and show that this gives similar constraints. The final result is expressed
as a likelihood curve for r, and yields an upper limit r0.05 < 0.12 at 95% confidence. Marginalizing over dust and r, lensing B-modes are detected at 7.0 σ significance.

http://arxiv.org/pdf/1502.00612.pdf

It was dying before but this is, as they say, the final nail in the coffin.