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Science Matters with Lawrence Krauss

Airdate: April 9, 2015
Arizona State University physicist Lawrence Krauss will talk about the latest science news in his monthly appearance on Arizona Horizon.

Guests:
  • Lawrence Krauss - Physicist, Arizona State University
Category: Science

Keywords: science, lawrence krauss, asu, news,

View Transcript
Ted Simons: Good evening and welcome to "Arizona Horizon." I'm Ted Simons. Governor Doug Ducey met with the state board of regents today to discuss a quote, “sustainable long-term business plan” to address the needs of Arizona college students and the needs of businesses that depend on the success of those students. At the same time, the governor said that deep cuts made to university budgets the past legislative session might be permanent and future reductions of state aid are possible. On Monday, Regents chair Mark Killian will join us on "Arizona Horizon" for more on the issue of state funding to state universities.

Ted Simons: The restart of the large Hadron collider and the crucial difference in mass are topics on the table tonight for ASU physicist Lawrence Krauss who joins for us his occasionally head scratching, but always enlightening look at the latest in science news.

Lawrence Krauss: I'm just scratching my head.

Ted Simons: Are you really? You've got those things on your shirt.

Lawrence Krauss: We won't talk about that.

Ted Simons: All right, the large Hadron collider, but we haven't talked about it in a while.

Lawrence Krauss: It's been upgraded. After the discovery of the Higgs particle, the machine was down for well over a year, almost two years while they upgraded it to improve both the energy and luminosity. The machine was designed to run at a much higher energy than it did two years ago but design issues meant that they couldn't get to where they wanted to get to, which is why we were so surprised they discovered the Higgs particle when they did because the design energy was to accelerate protons around the ring to an energy that's about 7,500 times the rest mass, which means they're moving -- they have an energy 7,500 times their rest mass, they're moving, I was working it out today, 99.999999% the speed of light. Three meters per second less than the speed of light.

Ted Simons: But not quite there. You can't get there.

Lawrence Krauss: They're almost as close as you can get and the energy is so high that we can -- that actually the protons' mass increases as you run it around the ring in both directions and we've increased the number of collisions that can happen. Before, there were roughly 20 million collisions each second. Now, there's going to be 40 million collisions each second. Twice the luminosity and each of these collisions generates tons of data. If you didn't reduce it, even after reducing it, every second there's several gigabytes of data being generated at the large Hadron collider. Thousands and thousands of gigabytes. This machine works as of two days ago, they got the machine going again at higher energy, the energy is going to be about twice what it was before. It will be the design energy. And the whole point of all of this is, of course, the higgs has been discovered but there's lots of mysteries. Why is the higgs there? Last time after all that effort, they discovered about 50 or 60 particles, which is not enough to explore its properties but what they're focusing on now and what we thought would be the first thing that would be discovered at the collider is the idea of dark matter. We've talked about dark matter, the stuff that dominates our galaxy. We think it's a new type of elementary particle created in the big bang, and we can look for it one of two ways. We can look for the particles left over from the big bang by building detectors underground or create mini big bangs in the laboratory and that's what the collider is doing.

Ted Simons: The collider, 17 some odd miles. It just basically goes like a bat out of you know what and they collide and you --

Lawrence Krauss: It's 27 kilometers around, underground. If you go to Geneva, you won't see anything but farmland but it's underneath there, goes under the mountains nearby Geneva, and it's got -- everything about it is amazing. It's got 96 tons of liquid helium cooling this whole thing down to a little less than two degrees above absolute zero with a vacuum deeper than the vacuum of space. There are fewer particles in that thing than the vacuum of space. The design properties were so daunting it was amazing it worked in the first place and that's one of the reasons. They couldn't get it -- it was so complex, it's the most complex machine humans have ever built, by far, and so it got working but not quite to where they wanted it to work, and now, it's going to come online, this isn't done quickly. The first beams have gone around the tunnel, and now they're going to ramp them up in intensity, it's going to take about four months to get them up to the intensity you want and then ramp up the energy. Sometime later this year is when it will be producing physics.

Ted Simons: And the idea is that when they collide, you will get what? The hope is perhaps an inkling of dark matter? Something that works within the theory of dark matter?

Lawrence Krauss: We have lots of ideas about what particles may make up dark matter, and many of them suggest there's a whole bunch of new particles around the energy that this accelerator could detect. When you accelerate the particles, you can produce particles that are essentially 7,000 times heavier than the proton. So with this new energy, and intensity, the idea is that every now and then in the collisions and you'll smash these things together and when the protons smash together, thousands of elementary particles are produced, thousands of them and hopefully, in that morass, there were some higgs particles but maybe will be the particles that were produced in the big bang, the dark matter particles and we could explore them and discover what it is that makes up most of the mass in the universe.

Ted Simons: In reading up on this, I saw supersymmetry involved.

Lawrence Krauss: You're a good student today.

Ted Simons: No flies on me first but explain to me what is supersymmetry?

Lawrence Krauss: There's a new property of nature, we call it symmetry of nature that says is for every particle we know of like protons and neutrons which I'll talk about in a bit, there's another set of particles that are very similar but much heavier. So it doubles the number of particles in nature, and it says -- it turns out that the new particle properties are not quite the same as the old particle properties but there's a new symmetry, there's double the number of particles in nature. You could say well that's amazing because we've never seen them or you could say we've already discovered half the particles in the universe. And if that is true, that will not only tell us about the nature of dark matter but it's a fundamental ingredient in certain ideas like string theory which may help us understand the origin of the universe itself. All of these ideas have been around for a long time. If we don't test them, we'll never know.

Ted Simons: All right, now let's get to the one that I can't wait.

Lawrence Krauss: You can't wait.

Ted Simons: The difference between neutrons and protons, the difference in their mass. Why is this a big deal?

Lawrence Krauss: Why is it a big deal? A calculation was just performed for the first time that explains why the neutron is heavier than the proton. Now that may not seem like it's earth shattering but it's responsible for our existence and we've never understood why. The neutron and proton make up the atomic nuclei in your body. The neutron is a little bit heavier than the proton. One part in a thousand heavier than the proton and, in fact, neutrons are unstable. They're radioactive. Since they make up most of your body, the amazing thing is if I get a neutron here, it will last 10 minutes before decaying, it's almost a miracle that that energy difference is so small, that mass difference is so small because when you drop a neutron in a nucleus, it gets bound. E=mc squared means it loses mass. It's now not heavy enough to decay into a proton, and it's stable. The whole reason atomic nuclei are stable is because that neutron-proton mass difference is so small. It was just a little bit smaller by a factor of two, then atoms would in fact, hydrogen atoms would disintegrate. If it's a factor of two smaller, it would disintegrate. If it was bigger, in the early universe, there would be so much helium that you wouldn't helium that you wouldn’t have hydrogen around to make stars. That mass difference is an essential part of why we're here but to understand it, it's very nonintuitive because the proton as you may remember from high school is charged. It's got electric charge. The neutron is guess what? Neutral. Got it? Since the proton has an electric charge, you think it would have more energy so the proton should be heavier than the neutron. But it turns out that the protons and neutrons are made out of particles called quarks and the quarks have different masses and protons have different quarks than neutrons a little bit, the makeup is a little bit different. So to understand that mass differential, you have to understand the theory of electromagnetism but also, the quantum theory of quarks, something called quantum quark dynamics. It's so complicated that in order to do the calculations to figure up what makes them up, it takes supercomputers. The supercomputers haven't been powerful enough until this year to do the calculation and predict that the neutron is heavier than the proton.

Ted Simons: Are we still in the theoretical realm or have we moved from calculations? Where are we?

Lawrence Krauss: The point is that the experiment was always ahead of the theory. We know the mass of differences. We just couldn't explain it. Now, we have a fundamental theory and we can, with sophisticated computers, we can use that fundamental theory and for the first time really explain these fundamental properties of matter that we knew were there all along and tell us why the theory explains that, in fact, neutrons and protons have the mass difference they do, if it was slightly different in either direction, we wouldn't be here having this conversation.

Ted Simons: And protons are forever?

Lawrence Krauss: No.

Ted Simons: No?

Lawrence Krauss: Well, it looks like they are in a way but we think that, in fact, ultimately and this is something we may get with the large collider, when we unify all the forces of nature together in a grand unified theory, we think protons may be unstable. So diamonds alas are not forever. However, their lifetime is roughly a billion, billion, billion times the age of the universe. So they're not a bad investment.

Ted Simons: Give or take a lifetime.

Lawrence Krauss: Exactly.

Ted Simons: So with all of this knowledge, it sounds like we kind of knew it, now, we knife know it even more. What does it mean for the future of everything?

Lawrence Krauss: It means we understand how to use this theory and this is the theory that's at the basis of nuclear physics, understanding the formation of all nuclei not just on earth, but in stars. This is the first time that we can really say we can use this theory, first of all, any time you can understand something so fundamental to our existence, it's important but we can then -- we have the technology and we can use it to understand both potentially developing new kinds of nuclei but also to understand how stars work. And the deep processes that happen in stars. So the theory has been so complicated that we couldn't manipulate it until now but now, we know, we have confidence that we can manipulate the theory, and now, we can use it to try to explain things we may not have understood before or to actually do kind of nuclear engineering, the same way we create new materials. We may be able to do that with nuclei. We don't know where we're going to go but it's a triumph of the human mind to finally have theories that we can vindicate that actually explain one of the most fundamental parameters in the universe, even if it didn't sound so interesting to you, if we didn't understand it, we would have no fundamental understanding of our origins and ultimately, we want to know how we got here and this is one important step in understanding from the big bang why you and I are here. And we should celebrate. We should go out for a beer afterwards.

Ted Simons: Why did you say I didn't find that interesting?

Lawrence Krauss: You surprise me every now, and then.

Ted Simons: Good to see you, thanks for joining us.

Lawrence Krauss: Good to be here.