Horizon, Host: Ted Simons

September 4, 2012


Host: Ted Simons

Lawrence Krauss on Physics


  • Internationally-famous physicist Lawrence Krauss of Arizona State University will talk about physics, with topics ranging from the discovery of the Higgs-Boson particle to the Mars “Curiosity” rover.
Guests:
  • Lawrence Krauss - Physicist, ASU
Category: Science   |   Keywords: Krauss, physics, rover, mars, science, ,

View Transcript
Ted Simons: Good evening, and welcome to "Arizona Horizon," I'm Ted Simons. What is the Higgs-Boson, has it really been found, and where was it hiding? For the answers to those and other current science questions I recently spoke with noted ASU physicist Lawrence Krauss. Always good to see you, thanks for joining us.

Lawrence Krauss: Always great to be here.

Ted Simons: Oh, it's good to have you. Last time you were on you took off. A few days later Higgs-Boson explodes. So I want to get your thoughts on that, because I've got you back. Before all that, we landed on Mars, we've got this "Curiosity" mission. What does a theoretical cosmologist look for on a mission like that?

Lawrence Krauss: First of all, it was very exciting. I watched it, I was in Australia right where the signals come in and are relayed from the deep space network in Australia. I was as excited as I had been since the moon landing, I think. It was so neat to watch. The really exciting thing about this mission, in principle it'll tell us if the conditions for life once existed on Mars. What I'm excited about, I expect we'll discover evidence of at least past life on Mars. But the big surprise would be if it weren't our cousin. We've discovered no planet is an island. Material from Mars comes to Earth. It gets knocked out by a meteors, makes its voyage to Earth. We found Martian meteorites in Antarctica, and it goes the other direction. And microbes can exist inside rocks. If there's life in one plant, it could easily pollute the other. Since Mars probably was hotter and wetter in earlier times, perhaps life on earth originated on Mars. If you want to know what Martians look like, just look in the mirror. For me I’d be very excited if ultimately there's evidence there was once life on Mars, and the big surprise from me would be if it was an independent genesis, that would really be amazing. So there are lots of questions, was there ever water on Mars? We really want to know the conditions, and this is the first mission that can tell us.

Ted Simons: What do we look for as far as daily reports and photographs; the information is flooding in and apparently is going to for quite a while. What do we start -- what's going on?

Lawrence Krauss: I'm sure NASA will let us know, NASA is pretty good about that.

Ted Simons: Yeah.

Lawrence Krauss: It's going to be slow, a month I think before the rover starts to move. It might be up to a year before it actually cracks open the first rock. It's going to be kind of slow. It was an exciting landing, but it's ramping up slowly. We just have to be patient. You can go online and see the most amazing images. I was looking at the interactive 3-dimensional cam where you can look all around the rover and focus down on the rover itself. To me it’s just like being there, I love it.

Ted Simons: So many of these photographs look like the drive to San Diego.

Lawrence Krauss: It looks just like Arizona, the Southwest. I don't know if we should publish that, that Mars looks like Arizona.

Ted Simons: We've had worse things said about us. What is the Higgs-Boson, and where has it been hiding all these years?

Lawrence Krauss: It's been hiding all around us. The Higgs-Boson, if it's there, and we think it's there, the data is remarkable and it's compelling that something's been discovered, and it looks very much like a Higgs. To me, it's the cap of the greatest intellectual journey in some sense that humans have ever taken, the development of the standard model of particle physics. 40 years ago we understood one of the four forces of nature, and now we understand three. Developing a mathematical and theoretical model of these forces suggested that two of the four forces which look very different, electromagnetism (which is responsible for the lights and the television we are talking on.), and the weak interaction, a very weak force but nevertheless powers the sun, they look very different. Incredibly different. The electromagnetic force operates across the whole universe. The weak force only operates across the nucleus. We discovered they could be different manifestations of the same force. The problem is, in order for that to be true, in quantum mechanics, the particle that conveys a force -- all forces are conveyed by particles. Electromagnetism is long range, because the particle that conveys electromagnetism is called the photon and it's massless. The particles that convey the weak force are very heavy (W and Z Bosons), they were discovered about 25 years ago and won the Nobel Prize for that. How can two forces, one conveyed by heavy particles and one by massless particles, really be different manifestations of same thing? This is where the Higgs comes in, and it was so slimy that I never believed it was true. The idea was that there is a background and invisible field throughout all of space called the Higgs field. The W and Z particles interact with the Higgs field. At a basic level all particles are massless. These W and Z particles interact with the Higgs field and get some resistance as they move. Therefore they act as if they are massive. It’s an accident of our existence. The photon doesn't, it remains massless. Because of that accident, the two forces look very different. It didn't take long for physicists to realize if this field is responsible for the mass of the W and Z, maybe it's responsible for the mass of all particles. Maybe some particles interact more strongly with the field and behave heavier, and some particles react less strongly and behave lighter and some, like the photon, do not interact at all.

Ted Simons: Well, how can the photon not react at all? How can it get thru this, I think you describe it as a cosmic molasses?

Lawrence Krauss: It is only a cosmic molasses for the particles that interact with it. The photon doesn't have any charge basically, doesn't have any electric charge or weak charge. Different forces in nature have different charges. The reason electrons are attracted to other electrons is because they are charged. However, the photon doesn’t have any of the quote “quantum numbers” that would allow it to interact. It's a remarkable accident of nature, it doesn't have to be that way. What it's saying in some sense is that our existence is an accident. It’s a cosmic accident based on these invisible fields. Invisible fields are not the subject of science, religion maybe, but not science. The neat thing that quantum mechanics tells us is, you hit the field hard enough in a little spot with enough energy, you'll kick out real particles. For the past 45 years we've been looking for a machine with the energy, that can have enough energy focused in a small enough region to smack the field hard enough to kick out the particles.

A Ted Simons: Are you saying the particle accelerator, whatever it's called over there, I thought the particles collide together. Are you saying the field collided?

Lawrence Krauss: At a small level, fields and particles are very similar. You take two protons and smash them together with enough energy, the idea is you if you smash them together with enough energy, can turn the mass of those protons into enough energy to excite this background Higgs field and kick out real particles. That's the way we're producing, we think, these Higgs particles. The neat thing is it’s a prediction. What made it so exciting, the first machine in a generation or more that's had the energy to in principle create the particles that we didn't know existed. I didn’t think they existed. The explanation just seems so pat, the idea that there's some invisible field throughout nature, it's just too easy. I thought nature would come up with another solution, and I'm kind of amazed. In the United States 25 years ago we would have had another collider had congress had the wisdom.

Ted Simons: And Arizona was involved in that a little bit, as well.

Lawrence Krauss: At the time they said it just cost too much, it was $5 billion, the air-conditioning bill in Iraq for one day.

Ted Simons: Back to the collider and what we saw there. Did we see -- are we seeing new particles develop when these two particles in the accelerator collide?

Lawrence Krauss: When they collide, each of those collisions produces sometimes thousands of particles. Because so much energy gets turned into matter.

Ted Simons: Does that suggest what could have happened at the Big Bang?

Lawrence Krauss: It takes us a lot closer to the origin of the Big Bang. What the collider does is, it takes us back to a millionth of a second after the Big Bang. That's really exciting. We think -- one of the things we've talked about in the past, this galaxy, our galaxy we live in is dominated by this stuff called dark matter, which we think is a new type of elementary particle, created in the very early universe. These particles are remnants, left over, that dominate the universe today. The neat thing about the collider is: If it can recreate those conditions in a very small region, it might not just create the Higgs particles, but it may also create the particles that make up the dark matter. We might not have to build detectors to discover the remnant particles from the big bang directly, but we might be able to create them. It's a race to see whether we create it first in the collider, or we build something to detect them.

Ted Simons: The dark matter comes to light; as it were. All right, the last question, because we've gotta get going here. We could talk so long, this is amazing stuff. But it seems to me like everyone got excited, we kind of almost think we sort of maybe found it. Did they find it or not?

Lawrence Krauss: We're very conservative. We've looked at billions and billions of collisions and many events. What is clear is: we have discovered a new particle. The particle appears to have the properties of Higgs-Boson. But we're very conservative because this is such an important discovery to say, you've discovered this particle that really is responsible for our existence and be wrong would be really kind of embarrassing. It quacks like a duck and walks like a duck, but we're going to wait to see if it's a duck. We don't have to wait very long, there will be three times more data than the collider had when it made the discovery. It'll allow us to test the properties of the particle. By the end of the year we should have a very definitive answer. Which is good, because the collider is turning off for two years, at the end of the year, for an upgrade. Stay tuned.

Ted Simons: We'll have you back to talk more about things like this, and your relationship with Woody Allen.

Lawrence Krauss: We'll talk about that.

Ted Simons: Good to see you.

Lawrence Krauss: Always great to be here.

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