The Big Bang theory wins again. So does Einstein.

It’s a great time to be a geek. We’re learning all sorts of extreme stuff. There’s a team led by John Kovac, from the Harvard-Smithsonian Center for Astrophysics, who’ve been beavering away on one of the fundamental questions of modern cosmology. The secret has demanded some extreme research in an extreme place. Antarctica. There’s a telescope there, BICEP2, that’s been collecting data on the cosmic background temperature. Last week, the team published their initial results.

Timeline of the universe - with the Wilkinson Microwave Antisotropy Probe at the end. Click to enlarge. Public domain, NASA.
Timeline of the universe – with the Wilkinson Microwave Antisotropy Probe at the end. Click to enlarge. Public domain, NASA.

The theory they were testing is as extreme as such things get and goes like this. Straight after the Big Bang, the universe was miniscule and very hot. Then it expanded – unbelievably fast in the first few trillionth trillionths of a second, but then much more slowly. After a while it was cool enough for the particles we know and love today to be formed. This ‘recombination’ epoch occurred perhaps 380,000 years after the Big Bang. One of the outcomes was that photons were released from the plasma fog – physicists call this ‘photon decoupling’.

What couldn’t quite be proven was that the early rate of expansion – ‘inflation’ – had been very high.

But now it has. And the method combines the very best of cool and of geek. This early universe can still be seen, out at the edge of visibility. That initial photon release is called the ‘cosmic microwave background’ (CMB), first predicted in 1948 by Ralph Alpher and others, and observed in 1965 by accident when it interfered with the reception of a radio being built in Bell Laboratories. That started a flurry of research. Its temperature is around 2.725 degrees kelvin, a shade above absolute zero. It’s that temperature because it’s been red-shifted (the wavelengths radiated from it have stretched, because the universe is expanding, and stuff further away gets stretched more). The equation works backwards from today’s CMB temperature, 2.725 degrees Kelvin, thus: Tr = 2.725(1 + z).

The COBE satellite map of the CMB. NASA, public domain, via Wikipedia.
The COBE anisotropic satellite map of the CMB. NASA, public domain, via Wikipedia.

The thing is that, way back – we’re talking 13.8 billion years – the universe was a tiny fraction of its current size, and the components were much closer together. Imagine a deflated balloon. Splat paint across the balloon. Now inflate the balloon. See how the paint splats move further apart from each other? But they’re still the original pattern of the splat. In the same sort of way, the CMB background pattern is a snapshot of the way the universe was when ‘photon decoupling’ occurred. It’s crucial to proving the Big Bang theory. It’s long been known that the background is largely homogenous (proving that it was once all in close proximity) but carries tiny irregularities in the pattern (anisotropy). What the BICEP2 team discovered is that the variations are polarised in a swirling pattern, a so-called B-mode.

The reason the radiation is polarised that way is because early inflation was faster than light-speed, and the gravity waves within it were stretched, rippling the fabric of space-time in a particular way and creating the swirls. Discovering the swirls, in short, identifies both the early rate of expansion (which took the universe from a nanometer to 250,000,0000 light years diameter in 0.00000000000000000000000000000001 of a second…I think I counted right…) and gives us an indirect view of gravitational waves for the first time. How cool is that?

Albert Einstein lecturing in 1921 - after he'd published both the Special and General Theories of Relativity. Public domain, via Wikimedia Commons.
Albert Einstein lecturing in 1921 – after he’d published both the Special and General Theories of Relativity. Public domain, via Wikimedia Commons.

What’s a ‘gravitational wave’? They were first predicted nearly a century ago by Albert Einstein, whose General Theory of Relativity’of 1917 was actually a theory of gravity. According to Einstein, space and time are an entwined ‘fabric’. Energy and mass (which, themselves, are the same thing) distort that fabric. Think of a thin rubber sheet (space-time), then drop a marble (mass/energy) into it. The marble will sink, stretching the sheet. Gravitational waves? Einstein’s theory made clear that these waves had to exist. They’re ripples in the fabric.

One of the outcomes of last week’s discovery is the implication that ‘multiverses’ exist. Another is that there is not only a particle to transmit gravity, a ‘graviton’, but also an ‘inflaton’ which pushes the universe apart. Theorists suspect that ‘inflatons’ have a half-life and they were prevalent only in the very early universe.

There’s more to come from this, including new questions. But one thing is certain. Einstein’s been proven right. Again.

Copyright © Matthew Wright 2014

Coming up: More geekery, fun writing tips, and more.


15 thoughts on “The Big Bang theory wins again. So does Einstein.

  1. Sigh. One of the things that discovery made me confront is my own limitations. Once upon a time I wouldn’t have hesitated to dive right in and figure it out, even if cosmology isn’t actually my thing. The sad truth is, though, “once upon a time” is long past. I hate to admit that I have a difficult to impossible time understanding what’s actually going on in anything like sufficient detail with respect to the mathematical analysis of the data. (Heavier sigh.) Oh well. I think there will be some interesting nominees for the Nobel Prize in Physics, and I also think they’ll deserve it. And it is pretty cool…I saw the pictures of the BICEP2 array down in the Antarctic, just like something out of a major SF movie. Also, the young physicist who was there who paid a personal call on the older, retired physicist to let him know his theory was vindicated, THAT was classy.

    But I admit it made me feel just a little … left behind.

    1. I scrabble to keep up with this stuff, these days, too. I did physics way back, won science prizes when I was at high school for a presentation I did on cosmology…but it’s way past all that now. For some reason, I can’t seem to keep away from dabbling in it, though…

  2. Good old Einstein he had it sown up with mathematics. While all this beavering is going on at brake neck speed the world itself is going to the dogs. Lets hope we survive long enough to answer these deep questions. Even NASA has some doubt on this point as shown by the reseach of Motesharri .

    Motesharri explored the factors which could lead to the collapse of civilisation, from population growth to climate change, and found that when these converge they can cause society to break down because of the “stretching of resources” and “the economic stratification of society into ‘Elites’ and ‘Masses’”.
    Using his Handy model to assess a scenario closely resembling the current state of the world, Motesharri found that civilisation “appears to be on a sustainable path for quite a long time, but even using an optimal depletion rate and starting with a very small number of Elites, the Elites eventually consume too much, resulting in a famine among the Masses that eventually causes the collapse of society”.

    1. I’m aware of that study though wary of it. Reducing disparate societies from divergent times, cultures and production bases to mathematical equations in order to draw a generalisation, as the study does, is fraught with danger. This is not to say that the predicted outcome is wrong. But I dispute the methodology, and the logic of the reasoning behind the conclusion, because I think it is too reductionist. Human societies collapse for various reasons of which resource over-consumption is the common one. But we must be careful about drawing too close a comparison.

  3. I’ve always been a fan of Einstein (even though I don’t even begin to understand his math), so I’m glad every time one of his theories are proven right. One question: how does this discovery prove the existence of multiverses? Is it to do with the ripples in space-time?

    1. As I understand it this is an outcome of quantum physics – the rate of expansion provoked ‘bubbles’ within the expanding cosmos, containing mini-universes. On this theory, of course, the whole universe is one giant zero-sum quantum event. I did physics, way back – but I scrabble a bit to keep up with this sort of stuff.

    1. Mine too. The field generates discoveries faster than I can keep up with these days & the days when I was actually devoting proper time to learning & thinking about physics are getting further and further behind me. It’s fun to keep prodding away at it, every so often, though.

  4. Thanks. That’s the best summary I’ve read. I’m interested but with no background in cosmology other than a little reading, it’s great to have an article I can understand (sort of!)

  5. Science has its place, but you’ll never convince me that the world just happened to appear like a magic trick. God spoke the world into place–hence, a big bang. He may have made it small then increased it; or he may have started it large, leaving a lot of guessing room. I think He had fun creating the universe. Can you imagine Him saying, “Let’s make a lot of them, they’re so pretty. Let’s make some with rings, how about a few going vertical and really keep them guessing. Oh, I know, let’s make one that looks like a huge eye watching them. That will really blow their minds!”

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