Cosmic Inflation and Gravity Waves

[geckzilla]

Polarization patterns imprinted in the CMB. Image Credit: Harvard-Smithsonian Center for Astrophysics

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This is the thread for today's big astronomy announcement. Here's what Shannon Hall at Universe Today has to say about it:

Astronomers have announced Nobel Prize-worthy evidence of primordial gravitational waves — ripples in the fabric of spacetime — providing the first direct evidence the universe underwent a brief but stupendously accelerated expansion immediately following the big bang.

Read more: http://www.universetoday.com/110360/lan ... z2wEfGLHrY

...

[/hide]

[Ann]

If this holds up, it's HUGE!!!

Ann

[geckzilla]

Phil Plait now has a blog post:

This is big news: Astronomers have announced that they have seen, for the first time, direct evidence of “inflation” in the extremely early Universe, unlocking an entire chapter in the history of the cosmos. It also ties together relativity and quantum mechanics in a deep and profound way, which has never been done before.

This news is very important, and very interesting. However, it’s also very esoteric–probably the most layered and complex announcement I’ve ever written about. It’s not like the Higgs boson, which could at least be summed up in a sentence or two. But this new work unveils a critical point in the history of the Universe, and has profound implications for physics.

Read more: http://www.slate.com/blogs/bad_astronom ... early.html

[rstevenson]

Phil Plait's article is much better than the first one linked above, mainly because it doesn't say the silly things that the first article does in its last two paragraphs. (If you ignore those last two paragraphs, it's an okay article.)

Rob

[geckzilla]

If you find any good reads on this, post them in here and then we can all vote which is the best at the end.

[rstevenson]

Good idea. Plait's article linked this one, but I'll put it here for quick comparison. It's much more technical than the other two posted so far www.preposterousuniverse.com/blog/2014/ ... ackground/

[Chris Peterson]

If this holds up, it's HUGE!!! :shock: :D :clap:

Huge. And not so much. I find it interesting, but not all that exciting... I guess because there is so much indirect evidence, that this new information doesn't really change much.

Huge was the discovery of the CMB. Huge is any discovery that changes the way we look at things. This new work is great stuff, but in the end, it just seems to be confirming what we were pretty sure we already knew. That's a very important part of the scientific process, of course, but I don't find myself getting too worked up about it.

[MargaritaMc]

If you find any good reads on this, post them in here and then we can all vote which is the best at the end.

http://www.jpl.nasa.gov/news/news.php?release=2014-082

http://www.bbc.com/news/science-environment-26605974

http://physicsworld.com/cws/article/new ... -inflation

http://news.stanford.edu/news/2014/marc ... 31714.html


The last one has this video

Click to play embedded YouTube video.

M
PS. Technical details and journal papers can be downloaded from:
BICEP2 2014 Results Release

[bystander]

Read more: http://www.universetoday.com/110360/lan ... inflation/

First Direct Evidence of Cosmic Inflation
Harvard-Smithsonian Center for Astrophysics | 2014 Mar 17

First Direct Evidence of Inflation and Primordial Gravitational Waves
California Institute of Technology | 2014 Mar 17

Physicists Find Evidence of Cosmic Inflation
SLAC National Accelerator Laboratory | 2014 Mar 17

[MargaritaMc]

Phil Plait's article is much better than the first one linked above...)

Rob

I agree - both for all the excellent links that he gives (like this Sky and Telescope article) and for the clear outline of why this is such an important find:

I know, this seems all very distant and removed from our daily lives, but in fact this is a very big deal indeed. Until now, inflation was a great idea—a critical one to understand the evolution of the Universe from the very first moment after its birth to the huge structures and details we see today—with no direct evidence. Now we have direct evidence.

Up until now this was all like trying to write a history book about the United States and talking about the Civil War without ever knowing exactly what happened at the time … and then finding photos and diaries and battlefields.

Phil Plait

I also found that this Guardian article published before the announcement was helpful, being written from a lay perspective.

If there is evidence for [primordial] gravitational waves, it would be a landmark discovery that would change the face of cosmology and particle physics.

Gravitational waves are the last untested prediction of Albert Einstein's General Theory of Relativity.
...

A note needs to be made that what is being referred to are primordial gravitational waves: evidence for the existence of gravitational waves dates from 1993.

Margarita

[FloridaMike]

If this holds up, it's HUGE!!!

Huge. And not so much. I find it interesting, but not all that exciting... I guess because there is so much indirect evidence, that this new information doesn't really change much.

Huge was the discovery of the CMB. Huge is any discovery that changes the way we look at things. This new work is great stuff, but in the end, it just seems to be confirming what we were pretty sure we already knew. That's a very important part of the scientific process, of course, but I don't find myself getting too worked up about it.

this is a very big deal indeed ... There are many different physical models of how inflation might have worked, and observations like this will be able to help us figure out which ones work, which ones don’t, and which ones might need tweaking. .... [NOW] We can understand what the Universe was like in the tiniest sliver of the first moment of its existence! These aren’t wild guesses, or just-so stories, or fanciful myths.

Phil says it’s a big deal. It sounds like it may be the first real evidence of something we have taken for granted for a very long time. I’d call that HUGE. Good call Ann.

[rstevenson]

Click to play embedded YouTube video.

I love that video! Only a geek (coming from me, that's a complimentary term) would announce the big news by saying "Five sigma, as clear as day, R of .2".

Rob

[Chris Peterson]

Phil says it’s a big deal. It sounds like it may be the first real evidence of something we have taken for granted for a very long time. I’d call that HUGE. Good call Ann.

Don't mistake what I said. But there's a big difference between a new discovery and a confirming discovery.

It is a big deal. A lot of scientists are going to be very pleased with this result (myself included). But very few are going to be surprised.

[MargaritaMc]

[youtube]
I love that video! Only a geek (coming from me, that's a complimentary term) would announce the big news by saying "Five sigma, as clear as day, R of .2".

Rob

Wasn't it lovely!! As an aspiring geek, I felt all warm and fuzzy...

Here is an interview with John Kovac on the Nature website
How astronomers saw gravitational waves from the Big Bang
Lead discoverer John Kovac describes his work at the BICEP2 radio telescope and how his career took him there.

[MargaritaMc]

...A lot of scientists are going to be very pleased with this result (myself included). But very few are going to be surprised.

University College London cosmologist quoted in The Guardian on 14th March 2014,
"If they do announce primordial gravitational waves on Monday, I will take a huge amount of convincing," said Hiranya Peiris, a cosmologist from University College London. "But if they do have a robust detection … Jesus, wow! I'll be taking next week off."

http://www.nature.com/news/telescope-ca ... es-1.14876
The findings are “on a par with dark energy, or the discovery of the CMB — something that happens once every several decades”, says Kamionkowski, who is at Johns Hopkins University in Baltimore, Maryland.

The strength of the signal measured by BICEP2, although entirely consistent with inflation, initially surprised the researchers because it is nearly twice as large as estimated from previous experiments. ...
The data pinpoint the time when inflation occurred — about 10^–37 seconds into the Universe’s life — and its temperature at the time, corresponding to energies of about 10¹⁶ gigaelectronvolts, says cosmologist Michael Turner of the University of Chicago. That is the same energy at which three of the four fundamental forces of nature — the weak, strong and electromagnetic force — are expected to become indistinguishable from one another in a model known as the grand unified theory.

Because inflation took place in the realm of quantum physics, seeing gravitational waves arise from that epoch provides “the first-ever experimental evidence for quantum gravity”, says MIT cosmologist Max Tegmark — in other words, it shows that gravity is at heart a quantum phenomenon, just like the other three fundamental forces.

[Chris Peterson]

...A lot of scientists are going to be very pleased with this result (myself included). But very few are going to be surprised.

University College London cosmologist quoted in The Guardian on 14th March 2014,
"If they do announce primordial gravitational waves on Monday, I will take a huge amount of convincing," said Hiranya Peiris, a cosmologist from University College London. "But if they do have a robust detection … Jesus, wow! I'll be taking next week off."

Surprised by the ability to detect them. Needing to be convinced that the results are valid. But not surprised by the existence of the primordial gravitational waves themselves. Not surprised by increased support for the inflationary theory.

It's like the discovery of the Higgs boson. Very big. Very important. Surprised almost nobody.

[Ann]

So now we have three "fantastic universal expansions" more or less confirmed: the Big Bang itself, inflation, and the accelerating universe. I find that so amazing - and to think that I used to worry about the contracting universe! (Well, maybe some scientist or other can still shake the contracting universe out of his sleeve.)

But seriously, these three epochs of fantastic expansion must say something fundamental about the universe. Don't you think so?

When it comes to inflation, it boggles the mind, certainly. What made it happen, and what made it stop? Well, I have heard the inflation of the universe being compared with the flash-freezing of supercooled water.

Click to play embedded YouTube video.

Yes, but even though inflation stopped, the expansion of the universe didn't - and now the universe is picking up speed again.

I sure, sure wonder what dark energy is, and how and if it is connected to whatever it was that got inflation going, and how it is connected to the evolution and fate of the universe.

Ann

[MargaritaMc]

If we are still collecting helpful articles on these findings,
this astrobite is really good.

Margarita

[Chris Peterson]

But seriously, these three epochs of fantastic expansion must say something fundamental about the universe. Don't you think so?

I think every observation of the physical behavior of the Universe says something fundamental!

The expansion of space makes me wonder about analogs to Newton's laws of motion. While universal expansion isn't motion in the classical sense, it nevertheless seems possible to me that ideas like force and inertia might apply.

I sure, sure wonder what dark energy is, and how and if it is connected to whatever it was that got inflation going, and how it is connected to the evolution and fate of the universe.

Dark energy itself isn't seen as being associated with the mechanism that drove inflation. Of course, in the very early universe, forces and energies that we see as separate things today were all mixed up. If so, you could say that everything is connected (that's the idea behind grand unified theories).

[MargaritaMc]

This is a link from today's Apod which has helped me.

The New York Times:

... Inflation has been the workhorse of cosmology for 35 years, though many, including Dr. Guth, wondered whether it could ever be proved.

If corroborated, Dr. Kovac’s work will stand as a landmark in science comparable to the recent discovery of dark energy pushing the universe apart, or of the Big Bang itself. It would open vast realms of time and space and energy to science and speculation.
Confirming inflation would mean that the universe we see, extending 14 billion light-years in space with its hundreds of billions of galaxies, is only an infinitesimal patch in a larger cosmos whose extent, architecture and fate are unknowable. Moreover, beyond our own universe there might be an endless number of other universes bubbling into frothy eternity, like a pot of pasta water boiling over.

‘As Big as It Gets’

In our own universe, it would serve as a window into the forces operating at energies forever beyond the reach of particle accelerators on Earth and yield new insights into gravity itself. ...
Marc Kamionkowski of Johns Hopkins University, an early-universe expert who was not part of the team, said, “This is huge, as big as it gets.”...

[neufer]

Click to play embedded YouTube video.

The New York Times:

If corroborated, Dr. Kovac’s work will stand as a landmark in science comparable to the recent discovery of dark energy pushing the universe apart, or of the Big Bang itself.

In our own universe, it would serve as a window into the forces operating at energies forever beyond the reach of particle accelerators on Earth and yield new insights into gravity itself. ...

[MargaritaMc]

This article at the Nature website,
All you need to know about gravitational waves
A beginner's guide to the BICEP2 discovery of primordial gravitational waves.
also has a useful explanatory video.
M

[ErnieM]

Full article from PBS Newshour (March 18, 2014) - http://www.pbs.org/newshour/updates/sci ... -big-bang/

Scientists believe that less than a trillionth of a second after the Big Bang, the universe began to rapidly expand as fast as the speed of light. The idea that the universe underwent a rapid expansion is called inflation. As the universe spread out and cooled down, atoms that later made gas, dust, stars and planets were formed.
But what exactly happened at the start of the universe has been unconfirmed until now. With a radio telescope at the South Pole, scientists followed gravitational waves 13.8 billion years into the past and found the first direct evidence of the universe’s rapid expansion immediately following the Big Bang.

“This is a totally new, independent piece of cosmological evidence that the inflationary picture fits together,” said theoretical physicist Alan Guth of MIT, who proposed the idea of inflation in 1980.

This is the first concrete evidence of gravitational waves, a phenomenon first predicted by Einstein 100 years ago. After major cosmic events like the merging of black holes or the Big Bang, gravity makes waves in spacetime that travel like ripples on a pond. These ripples travel at the speed of light, but Einstein thought they would be so feeble, they would be undetectable.

But scientists suspected that these ripples could still be found. Billions of years later, the waves are too weak to measure directly, so scientists have been looking for imprints left on the “cosmic microwave background”, a soup of elementary particles left over from the Big Bang. A U.S.-led team, headed by scientists at the Harvard-Smithsonian Center for Astrophysics, along with the University of Minnesota, Stanford University, the California Institute of Technology and NASA’s Jet Propulsion Laboratory, used a specialized radio telescope called BICEP2 (which stands for Background Imaging of Cosmic Extragalactic Polarization) at the South Pole to hunt for the gravitational waves. The dry air, thin atmosphere and distance from cell phone and radio towers made the South Pole the ideal wave-hunting location.

Finding these primordial gravitational waves is the “smoking gun” in inflation theory, said. Chao-Lin Kuo, assistant professor of physics at Stanford University. While you can never truly prove a scientific theory, this is testable evidence, he said.

“We’re not claiming that we definitely proved the theory,” he said. “It’s the closest to a proof you will ever get.”

The results will be submitted to a scientific journal this week for review and publication, said John Kovac of Harvard, who led the research project.

It’s the most exciting discovery in cosmology for 25 years, said theoretical physicist Lawrence Krauss of Arizona State University, who was not involved with the project. If the evidence of gravitational waves is confirmed, the discovery “gives us a window on the universe at the very beginning,” when it was less than one-trillionth of a second old, he told the Associated Press.

“If you want to know where did we come from, this is it,” Krauss told NewsHour. “We are the products of that burst in empty space.”

[Ann]

It’s the most exciting discovery in cosmology for 25 years, said theoretical physicist Lawrence Krauss of Arizona State University

To me that sounds a bit strange. To me as a complete amateur, the discovery of gravitational waves is a fantastic, brilliant triumph of technology and human perseverance and a wonderful step towards a "complete confirmation" of the Big Bang and the epoch of inflation. That's what makes this discovery so thrilling and so, well, huge.

But the most exciting discovery in cosmology for 25 years? What about the utterly unexpected discovery that we live in an accelerating universe, a discovery that also took a lot of human perseverance and technology? That discovery was made in 1998, sixteen years ago. Wasn't that bigger, if only because it forced cosmologists to completely re-think their ideas about the universe?

And anyway, if gravitational waves are the most exciting discovery in 25 years, then what was the exciting cosmological discovery that was made 25 years ago, in 1989?

Perhaps Lawrence Krauss is saying that the discovery of gravitational waves is so exciting because cosmologists have been trying so hard to nail these elusive waves, and the triumph of finally doing so, and getting confirmation that the standard model of cosmology has been on the right track for so long, is such an incredible rush. If that is what he is saying, then I can certainly sympathize.

Ann

[Chris Peterson]

It’s the most exciting discovery in cosmology for 25 years, said theoretical physicist Lawrence Krauss of Arizona State University

To me that sounds a bit strange. To me as a complete amateur, the discovery of gravitational waves is a fantastic, brilliant triumph of technology and human perseverance and a wonderful step towards a "complete confirmation" of the Big Bang and the epoch of inflation. That's what makes this discovery so thrilling and so, well, huge.

But the most exciting discovery in cosmology for 25 years? ...

I agree with you. This is very important, but it's still primarily a confirmational discovery. It's minor compared with Guth's original proposal of inflation (which has been verified by multiple lines of indirect evidence). If any of these guys get a Nobel Prize, and Guth doesn't, it will be a travesty.

I agree about the discovery of dark energy. And I'd add to that very important observations of dark matter. Both are profoundly important to cosmology- not more important than inflation, but more important than the strong confirmation of inflation, IMO.

I do think that some scientists are gushing just a little too hard about this.