Reeve wrote:I wonder if this will make Roger Penrose's cosmological model more testable. I seem to remember that his cyclic one was crucially dependent on gravitational waves with the predictions it made.

Ditto for Steinhardt & Turok's model.

The physics blogosphere is in overdrive, so for those want more reading material, here's an overview:

BICEP2 Team:
Frequently Asked Questions

Sean Carroll:
Gravitational Waves in the Cosmic Microwave Background
BICEP2 Updates

Matt Strassler: (the best posts I've seen thus far)
A Primer On Today’s Events
BICEP2: New Evidence Of Cosmic Inflation!

Adam Falkowski:
Weekend Plot: flexing biceps
Curly impressions

Luboš Motl:
Rumor: inflation-related primordial B-modes to be announced on Monday

Liam McAllister:
BICEP2: Primordial Gravitational Waves!

Shaun Hotchkiss:
"A major discovery", BICEP2 and B-modes

Peter Coles:
Some B-Mode Background
BICEP2DAY

Sesh Nadathur:
First Direct Evidence for Cosmic Inflation

Phil Bull:
How solid is the BICEP2 B-mode result?

So I wonder how long it will take for apologists to make up a reason that this doesn't count, that they knew it all along, that it proves god or that this is a conspiracy to remove god so people can rape each other.

I don't think it will bother them. They already say, some of them, that the bang happened but it was God who initiated it. The se kinds of discoveries will probably never harm religious claims. They just absorb them or morph to fit.

I agree that it will never harm people willing to bend their religion to accept the facts. But people like Craig aren't about bending religion to fit the facts, they are about making it seem like religion already knew the facts or that the facts somehow don't count because of personal revaluation. This kind of finding is damaging to creationism and apologists will try and turn it around or try and dismiss it to protect the believers.

Yep, that's kind of what I meant. It won't make them stop, or really harm them, because they just re-arrange the facts or what they say or what they supposedly knew or know to fit the current state of affairs.

Or they'll deny it, because you know, "science is too hard!" Argh!

surreptitious57 wrote:How can the existence of branes be falsified if they are impervious to light ?

Branes can't be falsified by these observations, but the brane-worlds cosmology can. I still haven't had a chance to see if the data impacts it in any way. I get the impression that the observations used only deal with polarisation, so not sure this is going to impact brane-worlds, but it is of course the first experimental observation of gravitational waves, so now we know they're there.

As for how it would be falsified, it's about the mechanism for the instantiation of the cosmos. In inflation, the gravitational waves result from the expansion of spacetime, but they are themselves stretched by the expansion, so their energy is shifted toward the red end of the energy spectrum (just like light waves are shifted toward the red by expansion). In brane-worlds, the gravitational waves are occurring on the brane itself, which is not expanding, so the waves are expected to be further toward the blue end of the spectrum.

And what exactly is a brane anyway ? I understand it to be multiple dimensional space separate to but part of a larger brane world [ in the same way that a
card in a deck is separate to but part of the deck ] What would be required to cause a brane to come into existence ? Do branes exist inside universes or universes inside branes ? [ I am assuming the latter ]

Not sure that a brane would be required to 'come into existence'. As for what a brane actually is, it's a construct from M-Theory, which is the unification of all the string theories along with 11 dimensional supergravity. In string theory, all the particles are made up of tiny vibrating strings, one dimensional filaments that vibrate in various patterns, and come in open and closed forms. The closed forms are loops of string. In M-Theory, strings still exist, but they form part of a larger landscape of branes (short for membranes, and generally referred to as p-branes, where 'p' refers to the number of dimensions they have). So, a string is a 1-brane because it's 1 dimensional, but you can also have 2-branes (sheets) and 3-branes, etc. So branes are polydimensional strings. In the brane-world, our cosmos resides on a 3-brane. All open strings have their ends tethered to the brane, which means they can't leave the brane they're on, while closed strings are not, and can travel between branes. Photons are open strings, so they're tethered to the brane they reside on, but gravitons are closed strings, which means that gravity can be felt between branes.

Our 3-brane is separated from another 3-brane by an additional dimension of space. The Big Bang occurred when these two 3-branes slammed together. There is, in this model, another cosmos, much like ours, residing on the other brane. Since gravitons can travel between branes, we feel the gravity of the matter on the other brane but, because photons can't travel between branes, it doesn't react electromagnetically in our cosmos, so we can't actually see it anywhere in the electromagnetic spectrum - dark matter.

If the Multiverse hypothesis is falsified by inflation

Well, it's important to be clear what we mean by 'multiverse hypothesis', because there are several hypotheses, and they're extremely different. Under the 'eternal inflation' proposal, inflation is required, so this observation supports a multiverse in that instance. It has no real impact on other multiverse hypotheses.

then does that mean the Big Bang can no longer even be hypothesised as the exact point at which the Universe began ? [ Universe is synonymous with Multiverse here so I mean in all space not just local space ]

In the eternal inflation model, we're just a black hole inside another cosmos. In reality, this doesn't impact any of that, because the observations only support (with the caveats concerning blue shift given above) a post-Planck cosmology at this point. We're still in a standard inflationary cosmology at this point, which is to say that it's the standard BB model with the modifications made by inflationary theory.

Would the laws of physics be different in each one or would they be the same ?

Hard to say at this point. There's Lee Smolin's 'cosmic selection' hypothesis, in which each cosmic expanse that's pinched of from a prior cosmos would inherit the laws of the parent cosmos with slight modifications (yes, a proper evolutionary theory applied to the cosmos), but in reality, I think such things are speculative. I still see no reason to suppose the laws of physics can actually be any different.

If inflation means the Multiverse is in a constant state of expansion does this not invalidate the Second Law Of Thermodynamics ?

Well, that's what some apologists would like to think, which is why they're always running around screaming 'BVG Theorem' at the tops of their lungs as if they know what it implies. In reality, we would need to know the details. It is simple enough to imagine that the formation of the black hole that constitutes the birth of a new cosmos could reasonably bring about the extreme low entropy conditions required. The simple fact is that we have no idea of how to apply the 2LT to the cosmos, and indeed, if eternal inflation is correct, the the cosmos is not an isolated system. It's a closed system at best, and possibly an open one, in which case we can forget about the implications of the 2LT in this regard. It's why I always advise people not to erect thermodynamic arguments to cosmology, because they're always fallacious. I only refer to thermodynamics in this sense to shoot down other references to thermodynamics in this sense.

Would every Universe in the Multiverse be expanding beyond c and would that speed be identical in all of them or different in each one ?

Unknown. My feeling is that c is constant in all cosmic expanses, because again, there's no reason to suppose that the laws of physics could actually be different.

For more info on 'brane-worlds', read Neil Turoks excellent The Elegant Universe. Also Cali's excellent expo of the original papers can be found HERE.

Hope some of that helps.

Now to have a shufty at the links Pulsar kindly provided. Johnny 5 need input!

Jester blogs on this finding: RÉSONAANCES: Curly impressions

"If this holds" is the central question now. This sort of experiments is difficult and subject to pesky instrumental effects and systematic effects due to foreground emission. It's not impossible that BICEP screwed up; in fact, experts point out some worrying aspects of the data, for example the excess in the BB spectrum at high multipoles. So I would say at this point it's fifty-fifty. Fortunately, there are many experiments out there with similar sensitivity (Planck, ACTPole, SPT, POLARBEAR) that should be able to confirm or refute the claim in the near future. In particular, the release of Planck polarization data this year should straighten many things out.

But as he notes, the inflation energy scale, about 2*10^(16) GeV, is rather entrancingly close to the gauge-unification energy for the Minimal Supersymmetric Standard Model. So there may be some GUT connection.

I say 'Checkmate, Creationists' on Twitter, someone replies with this:

lol yes Science closer to proving Genesis, an always existing universe would have dealt a fatal blow

??????????????

The person seems to have issues with atheists, and she particularly seems to revel in stirring up shit with Prof Brian Cox.

He clearly doesn't understand that this opens the door for an eternal universe. Hardly a 'smoking gun', but confirms part of a theory with that feature.

Ironclad wrote::wave: Hey Katherine, long time no see.

Hello again - I have spent much of my absence having sparring matches with 'the opposition' on Twitter!

Going to try and post here more often.....

And so you should. There's a whole truckload of Cillit Bang gone unused, and the dead arguments are really starting to stink the place up!

Very nice to see you, sweetie.

APOD: Astronomy Pic of the Day:

http://apod.nasa.gov/apod/astropix.html