Name: Cosmic Superstrings - Sixty Symbols
Uploaded: 2020-03-30T05:13:45.000Z
Duration: 28 min 42 s
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those of you who follow us on Twitter or Facebook might know that our very own professor, Ed Copeland, recently won a prestigious medal from the Institute of Physics.

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It was a great excuse to go and have a night out and amazingly see Professor Moriarty in a bow tie.

But here it 60 symbols, of course, were especially happy for Professor Copeland.

Now, his wind has nothing at all to do with 60 symbols.

He's won it for his own research into three areas.

Of course, we're talking on a cosmic scale here and dark energy.

So we're gonna post three videos, one on each area of research on I really let off the leash a bit here, so it's gonna be talking for quite a while, but I know a lot of you always say you want to hear more from the professor's.

Here's the first of three videos with head on.

This one is cosmic strings and super strength.

You know, when they announced the Nobel price on duh they announced it two Higgs and on Blair who quite rightly received the prize.

They didn't give it to Kimble, which, uh, upset me badly because Tom was a good friend.

But also, I think he probably deserved it as much as they did.

And so I tweeted a few minutes later and I said, You know, congratulations to Higgs non gleefully deserved by I feel sorry for Tom, and what we now need to do is gone.

Find cosmic strings so that he can get his own Nobel Price.

Because Tom Cable came up with the idea of cosmic strings back in 1976.

First of all, you need a riel imagination to come up with these kind of things.

They are made up of what we could call the Higgs field, but just a completely different energy.

Cosmic strings are examples of something called atop a logical defect.

These are objects that formed in the vet may have formed in the very early universe.

There's no evidence yet of their existence on DA.

And so I'll just try and describe give you an idea of them.

Their thickness is much, much smaller than a proton.

OK, so you've no chance of seeing them, but they can be a CZ long as the observable universe.

Moreover, if you had about a kilometer of such a string, it would have the mass of the earth.

So there is much thinner than a proton, but that the mass of the objects are the energy stored in the objects Would be of a kilometer of them would be about that of the Earth on dhe.

They formed these particular ones would have formed within the 1st 10 to the minus 35 seconds after the Big Bang.

You just need quite an imagination to think about these things on dhe they formed in the first transitions, just as we've been hearing about the Higgs field undergoes face transitions.

And as it undergoes this transition, where it changes from one state to another state, it can give masses to the particles.

In this particular case, what happens is that the equivalent field, but at a much higher energy as it changes from one high energy state to another under a first transition throughout the universe.

There are various parts of the universe where it were.

A bit of the original high energy bet gets trapped on these air formed the lines thes long strings so that the strings of the original high energy bit That was before the first transition on the surrounded by the new phase, which is at the lower energy on once they're formed, you haven't.

You have a network of these long strings crossing across the universe and loops of string on, then there because they're so massive.

And then there's so much tension they begin to flop around, and as they flop around, moving at close the speed of light or about half the speed of light, they begin to cross one another.

So you imagine a long piece of string like a shoe less Okay, imagine a shoelace and you as it wraps back and crosses itself.

But with a shoe less, you can't do anything.

It can chop off at that point where where a piece of string crosses itself, Then at the junction where they've crossed it will break These loops of string now are under a huge tension.

Remember Kilometers, about the mass of the earth there are selecting around that.

Moving close to the have been a good fraction of the speed of light on because they're moving and oscillating, they radiate.

They radiate gravitational waves, just like any massive object that moves will radiate gravitational waves.

And that's its principal way of losing energy.

Because if they didn't do that, what would happen is the long strings would just keep Stretching as the universe expands is be like pulling an elastic band on the energy stored in these long strings would get bigger and bigger and bigger, and eventually they would come to totally dominate all the other contributions to the energy in the universe.

And it would completely change the dynamics of the universe.

We don't seen any, so either they're not there or something else has happened, which is meant they don't dominant on.

The thing that we think happens is that because these long strings conform loops on these loops can then radiate their energy and gravitational waves, Then they can reach what we call a stable scaling solution where the energy stored in the strings becomes a constant fraction of the total energy.

So it never comes to dominate the energy and the strings doesn't disappear.

Just becomes like the Goldilocks amount of energy is just right.

And that was what got people very excited.

When Tom Cable first came up with this amazing idea of the formation of these objects, he demonstrated that when they evolve under the expansion of the universe that they were chop off these loops and they would radiate away their energies in just the right amount so that they overall energy of this network of strings would be some fixed fraction of the background energy.

Now it turns out you can work out what that fixed fraction is on it and use.

You find that for for first transitions which correspond to what we call the grand unified phase transition.

That's where we unify the strong electoral week and the electromagnetic forces.

This is about 10 to the minus 35 seconds after the big bang that the energy scale associated with that which determines the masses of these strings that is just sufficient to lead to the fluctuations in the matter that producers the cosmic microwave background radiation on the distribution of Galaxies.

This was what it seemed to be the case back in the 19 seventies and early 19 eighties, that cosmic strings provided that the seeds from which structures would fall so people so no, we had a theory which was rivaling another theory called the inflationary universe, but they were competing with one another.

Unfortunately, about the time I started working on these theories, um, they the evidence from the cosmic microwave background was coming in and it was getting better and better.

You could see the fluctuations in the temperature of the microwave background in all different sizes across the across the university observable universe.

And you could begin to fit your predictions from cosmic strings with what you observed in terms of what this distribution should be and you found cousin and it was found that cosmic strings just weren't working.

They were not matching the observed cosmic microwave background on our Satrapi's, and so people began to lose interest.

These wonderful objects that could well have formed in the early universe on, I should say that the analog objects that have been observed in converts, matter systems there, observed in liquid helium systems there observed insistence with dramatic liquid crystals, the scaling properties a roll scene and match what you might expect from cosmology.

It's just that they're not been senior in cosmology.

So back in the turn of the end of the 19 nineties beginning of 2000 people began to lose interesting these objects because they were not doing what they were, it said.

On the tin in particular, when you look at the observed map and look at the power in the map has a function.

If you like of the of the angle of the sky that you're looking at, it's got a very distinctive set of peaks and troughs.

They called the Doppler peaks and troughs.

When you compare that with what the prediction is from cosmic strings, basically, the cosmic strings would give you one peek.

Andi no, the second repeats not the Secondly Doppler Peaks I carried on because I was interested in some of the features.

There are some, as I mentioned just a few minutes ago, that there really Iraq on this matter systems, which demonstrate these and and in fact, there are a number of convents.

Matter systems, which are driven by loops of voter, sees, loops on off effectively of strings.

And there's a a particular thing called the Vine and Equation, which which is used a lot in helium.

And no one's really been able to derive that equation from first principles.

And I think there's a way of doing it from the work we did on.

So that was something I carried on working on and still am thinking about with Tom and Danny Steer, but basically the idea of using strings in cosmology.

Yeah, we stop thinking about that for a little while.

And it wasn't until about 2002 when I was, in fact, early 2003 I went to a meeting in Santa Barbara, one of the perks of working in this field, and when I was there I got chatting to a few people who who were thinking about a different type of string.

They were thinking about what we might call fundamental strings off the super strings of string theory.

Back in the 19 eighties, people were working on that.

And if that was probably the most brilliant theoretical physicist alive today, Ed Witten had had asked the obvious question, If you have cosmic strings and if you have these fundamental strings, maybe they're the same thing on he'd come to the conclusion that couldn't be basically on the fundamental string.

Turn out to be very unstable if you If so, if you formed a string that was, you know, the size of a galaxy than a fundamental string would just want to chop up incredibly quickly.

Um, he also discovered that if you if you looked at what the natural value waas for this mass of the fundamental string, it was where two big compared to what observations were telling you the cosmic string could be.

And so there were these reasons why you know, the instability, the fact that the masses didn't work out, which meant that the feeling was they wouldn't want to work.

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Cosmic Superstrings - Sixty Symbols

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