Krauss on Science

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Arizona State University Physicist Lawrence Krauss makes his monthly appearance on Arizona Horizon to enlighten us on the latest science news, including the discovery of a very earthlike planet and an exomoon.

Ted Simons: ASU physicist and best-selling science writer Lawrence Krauss joins us every month for the latest in science news, which this month includes the discovery of an earthlike planet in a far-off solar system. Here now is Lawrence Krauss. Good to see you.

Lawrence Krauss: Good to be back.

Ted Simons: What is Kepler-f?

Lawrence Krauss: Don't you know?

Ted Simons: No. [ Laughter ]

Lawrence Krauss: It's our cousin, it may be a cousin of our earth. As you may know, Kepler is a satellite that was incredibly successful at finding planets around other stars and over I think at least 2,000 such planet candidates were discovered. Kepler has sort of stopped its mission because it's not working as well anymore. But part of the effort is to look for potentially life elsewhere in the universe or habitable planets. We're looking at one of the -- what Kepler discovered is many solar systems around other stars. In fact, we know that most stars have planets around them and Kepler-186 is a system, 500 light years away from us. It takes 500 years for the light to get us and our solar system has eight or I believe nine planets, and the Kepler star is a star that's about half the size of our sun, and that means it's much less bright, and there are five planets in that solar system and one of them, the outermost planet, now appears to be a planet that's about the size of the earth and it's in a region which could have liquid water. So it's in what's called the Goldilocks zone.

Ted Simons: And apparently, we know that it's likely a rocky surface, not gaseous, liquid maybe water, not ice. How do we know all this?

Lawrence Krauss: We don't know it all. We're surmising based on its location, and size that it's likely to be a rocky planet but we don't know for certain. We have to make suppositions. The way these planets are discovered, we've talked about this before is when they go in front of the star, they make it a little dimmer and all we can see is the dimming and that tells us the size of the planet basically. And there are five of them around this system. And it's amazing that this technique even works because, you know, if you look at the sun it's pretty bright and you try to see a little dimming of the light. But it's done it. We know the size of the planet and its distance, the orbital distance, and those things together tell us likely the temperature on the planet and given its size, it's probably a rocky planet but it could be a very small gaseous planet, we can't say that from the existing data but it's exciting, although it's not earth, the star is about half the brightness of the sun as I say and that star is much cooler on the whole than the earth is but just enough that liquid water could arise there. It's been estimated the amount of sunlight is receives is about the same as Mars. It's not a twin. It's at best a cousin but it does suggest as, in fact, all the evidence that the galaxy is just full of earth-sized planets. And the question is will we find a twin and then if we find a twin, will we be able to find out if it's rocky, look for an atmosphere, we're not going to do that with Kepler but there's a whole bunch of new satellites that are being launched that will hopefully try to do that.

Ted Simons: This thing is 500 light years away?

Lawrence Krauss: It's our near neighbor.

Ted Simons: Yeah, how about --

Lawrence Krauss: Take us 400,000 years if we left in a rocket ship.

Ted Simons: An exomoon. Is this the same thing?

Lawrence Krauss: Exo means it's outside of our solar system. We've never seen any moons. We may have. We don't know for certain. It's a very different technique, has been used to find a very strange pair of objects. Something called microlensing. It's an amazing phenomenon, prediction of general relativity. You're seeing images of what this thing might be but what happens is when again, when an object passes in front of a star, if it's small enough, what happens is it actually bends light around it, we all bend light because gravity bends around massive objects, and if it's small enough, it doesn't produce many images of the star but it basically brightens, it causes the star's brightness to be enhanced. You see a little bit of brightening. What we've seen here is was two little bits of brightening telling you that in front of some distant star, two objects are moving. In this case one object was 2,000 times the mass of the other. So that could be either a Jupiter, small star with a Jupiter-like planet or a Jupiter-like planet with a moon the size of the earth. Unfortunately, it's one of these once in a lifetime observations. Unlike seeing the planets that go around stars, where you can keep seeing the phenomenon repeated, this is just a lucky observation, you look at a star and if you're lucky, something passes in front of it, you see it once, you won't see it happen again. And so it's just a one-time event and moreover, if it's really true that it's a planet and a moon, it's a planet that got lost. It doesn't have a star around it.

Ted Simons: Do we know whether it's orbiting something? It could be like lost in space.

Lawrence Krauss: It's most likely lost in space, there's no other objects near it because we don't know a similar enhancement and that means it could have been a planet that got knocked out of its solar system as happens periodically, knock it out of the solar system. Happily it hasn't happened in our solar system in a long time but it could be a frozen planet that's been knocked out into the cosmos, maybe a planet that had well unlikely a planet that had life on it but if it's true, it would be, if this really was a Jupiter and earth sized planet it would be the first moon that's been seen outside our solar system. We're sure that there are moons around many of these planets because look at our solar system, almost every planet has moons around it but using the transit method, they're too small to see. This was just a lucky accident and the amazing thing is if you keep -- I've said this before, the universe is old and big and if you keep staring at objects long enough you'll have a lot of lucky accidents. You can't repeat it. So it's a little less interest than the transit method, you see it, it's come and gone and you really don't know what it was but it's suggestive that at least we may have discovered another moon.

Ted Simons: How far away?

Lawrence Krauss: We don't know. We don't know that. We can just see the object enhance the light from a distant star, it's probably far away, somewhere between us and the center of the galaxy. So if you thought 500 light years was far away, this is even further.

Ted Simons: That's a real road trip. All right. Help me with this one.

Lawrence Krauss: I know you're nervous about this one.

Ted Simons: I'm nervous about this one because apparently, we've discovered a different kind of cork. I don't know what a regular kind of cork is.

Lawrence Krauss: It's a kind of cheese but I want to talk about this because I want to go from outer space to inner space. We've been talking about cosmological things but it's nice to point out we're made of quarks. It was one of the great discoveries of the 1960s that the particles that make you and I up, the vast array of many elementarily particles could be understood as being made up of these fundamental particles called quarks, there's three quarks in every proton and neutron. There are other particles. But you are quarks and electrons. A very nice combination but quarks and electrons. These are the fundamental building blocks of nature. For 50 years we've known about quarks as a way to categorize all the elementary products we see. Three quarks make up these particles, a quark, antiquark. Some people have speculated there may be exotic particles that are made of more than three quarks. Now with the large hadron collider, a particle has been discovered made of four quarks and we don't know how that works. Because we understood the three quarks and the quark antiquark. This is an exciting new discovery. It's not earth shattering but it teaches us something. There are new things under the sun. You may think quarks, we know all about them, it's all been discovered, we're going to look for exotic stuff like the higgs particle and it's interesting to realize that under our noses with stuff as normal as quarks, even though that seems strange to you, they were named quarks, this model that could explain everything we saw in the 1960s, called the eight fold way. All of the weird particles that had otherwise appeared unclassifiable could be understood as combinations of quarks. He won the Nobel Prize. It was a great discovery and it sounds like old physics but even in that old physics we've discovered something new that we don't understand and I like that.

Ted Simons: So what is the impact on the understanding of the subatomic world?

Lawrence Krauss: It tells us something about the strong forces that hold quarks together and it allows us ways to test our ideas of the models of the structure. The strongest force in nature, it takes an infinite amount of energy to pull two quarks apart, you can't do it and it was only in the 1970s that we had a model for how it work. We're trying to understand that model because strong interactions are hard to understand mathematically because they're so strong that the mathematics get quite complicated. So every bit of new and surprising data helps us understand that model. It's not going to change the world. But it means that there are surprises, even under our noses, and just like the weird new moons and planets to be discovered up here, even under our very noses in the materials that make us up, there are new unexpected elementary particles that may exist and that teach us more about ourselves. I kind of like this.

Ted Simons: Are there going to be other oddities? What else is waiting for us?

Lawrence Krauss: We're looking. This is an oddity that was sort of surprising but maybe not earth shattering. What we're hoping, the large hadron collider will turn on again in 2015. We are hoping that we'll see real oddities because the higgs particle was a great discovery. This is an interesting discovery. But we're hoping that we might see a whole class of new elementary particles called supersymmetric particles which would help us understand the fundamental structure of matter and might explain dark matter. We are really hoping when that machine turns on with more energy and more intensity, we will be flooded with new surprises that you and I can talk about.

Ted Simons: Oh, boy. A supersymmetric particles. Are they smaller than quarks?

Lawrence Krauss: Yes. Well, they're point-like particles but they're more exotic. They make quarks seem like a kind of cheese.

Ted Simons: I see. So basically, we've got quarks, we've got the outer space world with the new moon found and the once-in-a-lifetime moon and the planet found. What's next? What's on the horizon? What do you think we'll talk about next?

Lawrence Krauss: Well, that's the great thing. That's the great thing. We don't know what we're going to talk about next month. That's why science is fun. We don't know what discoveries are going to be made. And so with each month, it's an interesting challenge to see what's going to happen. We can predict the large hadron collider is going to turn on, we can predict when the large satellite comes out that will look for new planets, so we can expect to see those things but discoveries as I like to say it if I knew what the next big thing was I would be doing it right now.

Ted Simons: And not only that when the hadron collider comes on, stronger more powerful, bigger, better, it could mess up a whole lot of previous theories couldn't it?

Lawrence Krauss: Well, I like to think so. Because it's fun to find out that we're wrong because it means there's new things to learn. I expect it won't mess up the standard model but it may -- what really importantly it will do is give us a direction to understand where to go next, which is what we really need.

Ted Simons: We've got to stop right now, always good to see you. Thanks for joining us. Friday on "Arizona Horizon," it's the Journalists' Roundtable. The legislative session is over. We'll discuss what lawmakers did and did not get accomplished. And an appeals court okays a lawsuit challenging Arizona's expansion of Medicaid. That's Friday on the Journalists' Roundtable. That is it for now, I'm Ted Simons, thank you so much for joining us. You have a great evening.

Lawrence Krauss:Physicist, Arizona State University;

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