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Hank explains how a recent astronomical discovery made in Antarctica could change what we know about the birth of the universe, and the rules of physics that govern it.

Stanford Professor Andrei Linde Celebrates Physics Breakthrough:

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 Two physicist get a visit

So a Stanford University physicist walks into a house and announces: "It's 5 Σ R at .2". It's not a joke. It's physics talk. The house Chao-Lin Kuo walked into was that of Renata Kallosh and Andrei Linde, and that married couple of theoretical physicists looked at Chao-Lin as if he just told them that the house they live in is an inter-dimensional magic box that can travel through time and space.

Actually he is confirming a theory that Linde has been working to refine and support for decades. It's a beautiful thing. They're... they're dumbfounded. The link is in the description, you should give it a watch. It will make your heart melt. And then come back and I'll explain.

[intro music]

 Cosmic inflation

So, what the heck does "It's 5 Σ R at .2" mean? Well, probably it means that suddenly we understand way way way more about the universe than we did four days ago. So much so that we are interrupting our regularly scheduled SciShow to bring you this news. 'five sigma' (5Σ) basically means that there is a 1 in 3.5 million chance that the signal they're seeing is a coincidence, a fluke. Only at 5Σ are physicists ready to call a signal real. They're a careful bunch.

So what is this signal? The mysterious 'R at .2''?

Well, let's start at the beginning. Actually, not quite the beginning. Like, a billionth of a billionth of a billionth of a billionth of a second after the beginning. This infancy was a tumultuous time for the universe, as it expanded far faster than the speed of light, producing an amazing amount of radiation. This theory that the universe expanded extremely quickly in the first few moments after the Big Bang and then slowed way down is called 'cosmic inflation'. And it's pretty well accepted because the math works so well, but there isn't actually a lot of experimental data supporting it.

Wonderfully enough, we can study inflation because at the edge of the observable universe, the radiation it produced is just finally reaching us after a 13.8 million year trip. And that's what these scientists are up to.

 Gravitational waves

With the radio telescope positioned at the South Pole, to observe radiation produced by our sun, called BICEP2, they've been detecting that cosmic microwave background. We've been studying the cosmic microwave background for decades, but this week the news was released that that radiation was polarized in a way that could only have been caused by gravitational waves.

These are waves in space-time that Einstein predicted in 1916, but they require so much energy to amplify them enough to make them detectable that we have had very scant evidence of their existence so far. This new data first confirms the theory of inflation proposed thirty years ago by Alan Guth and refined by Andrei Linde, whose house we were at when we started this journey.

 Theory of everything

Not only that, but it may also bridge the gap for the first time between the two major theories of physics: quantum mechanics, which explains the behavior of the very small, and general relativity, which explains how objects that we're used to interacting with behave. Both of those theories are very well understood, but in very weird ways they seem to obey different rules. It's like they come from two different universes.

Gravitational waves have been seen for a long time as the potential link between these two theories, and this new method of detecting and studying them could help us draw the four fundamental forces of physics -gravity, electromagnetism, and the strong and weak nuclear forces- into one cohesive theory of everything.

So not only are we seeing our cosmic birth in a whole new way and with a whole lot more certainty, but it's shedding light on what is, I think it's safe to say, the biggest mystery in modern physics.

Pre-emptive congratulations to those involved in their Nobel Prizes, which I'm sure are forthcoming - what they have learned is going to be bearing fruits of knowledge on us for quite a while. So look forward to more of that here on SciShow.