Horizon, Host: Ted Simons

February 18, 2014


Host: Ted Simons

Krauss on Science


  • Arizona State University physicist Lawrence Krauss makes his monthly visit to the Arizona Horizon set to discuss the latest science news, including news about the oldest star.
Guests:
  • Lawrence Krauss - Physicist, Arizona State University
Category: Science   |   Keywords: science, krauss, physicist, asu, star, news,

View Transcript
Ted Simons: Good evening and welcome to "Arizona Horizon." I'm Ted Simons. ASU physicist and best-selling science writer Lawrence Krauss joins us each month to discuss the Earth and stars and, and lots of things in between. And here now is Lawrence Krauss. Good to see you again.

Lawrence Krauss: It's good to be back, as always.

Ted Simons: And I'm glad you are here because I heard last night that we got buzzed by asteroid, and I am thinking, should we have been hiding under our desks?

Lawrence Krauss: If it did get that close, if it hit you, you could not do anything about it, but most likely you wouldn't. There was one that came close that we saw. It's bigger than the one a year ago, in Russia, the size of three football fields or something like that, and it came maybe a million or 2 million miles from the Earth, which is close but no -- but no cigar, and even if it hit the Earth it would not have caused massive devastation. The ones that would cause massive devastation, as we talked about before, would happen much less frequently. But, you may be concerned that we did not know about it until relatively recently.

Ted Simons: Yes, that is -- I'm just saying --

Lawrence Krauss: You look a little worried.

Ted Simons: Yeah. It's nice to know that we found this out but like we found it out late from the game.

Lawrence Krauss: We are trying to build a network, which will allow us to look at asteroids or comets smaller and smaller. We can see kilometer size -- three times the size of this one. But there is a network planned that will go down to things that are meters or so, and we'll be able to know about it in advance, and that would be useful, perhaps. But, as I say, the small ones, there is tons of material every day that hits the Earth. Lots of stuff is hitting the Earth. Most of them don't make it to the ground. In fact, the one, the one that was in Russia, the actual size of the object says that made it to the ground are very small, they burn up in the atmosphere and, and you have to get much bigger before you have to worry about massive devastation, and if, if one of those comes, we'll have maybe a few years of notice, and maybe we can do something about it.

Ted Simons: We’ll do a special show on it.

Lawrence Krauss: Absolutely.

Ted Simons: And quickly, the difference between a comet and Asteroid.

Lawrence Krauss: Comets are large snowballs, asteroids tend to be rocks, they are both coming from the outer part of the solar system. Comets are interesting ice material that, basically, is mostly the water, which may fill up the Earth, and they are all directed to the inner solar system by gravitational systems due to Jupiter or a nearby star, and they come through, and as I say, the frequency of the really large ones, the ones that would really be life threatening for everyone on Earth is 100 million years, and so it's not something that you have to worry about on a daily basis.

Ted Simons: Ok. And they are old, too. Speaking of old, it sounds like there is new research or something regarding older stars, not way out in the hither lands there, but in our own galaxy.

Lawrence Krauss: Our galaxy is old, and we know it's at least 12 billion years old. One of the things I worked on is to determine the age of the galaxy, so, we think that galaxies form within the first billion years or so, or maybe a few hundred million years, after the big bang, and we can look at really old ones far away, but our galaxy may have remnants of really old stars, and doing this stellar archaeology, is a neat new field because we could see how do we know a star is old, the answer is, because it does not have stuff like you and me in it. As I have said, all the elements that make you and I, carbon, nitrogen, oxygen, they were not created in the big bang but in the fiery, nuclear furnaces of the cores of stars. The only way they could get into our bodies is if the stars were kind enough to explode, and then they spewed out the material, and then a second and third and fourth generation of stars would use that material and process it. So, all the atoms in the body have been probably through many stars. We are, we are stardust. If we are looking for old stars, we are looking for stars that don't have those heavy elements, and we classify it by the amount of iron in a star. The abundance of iron, and wire looking for stars that have initially one one thousanth, of the abundance of iron of the sun one ten thousandth,ten thousandth. Earlier this month, new reports came from the oldest star that's been discovered in our galaxy, whose abundance of iron is less than one ten millionth of a millionth of the sun, which means the material that made up that star was probably processed in less than one or two generations of stars, so we're looking, we're, we're looking at the remnants of the oldest objects in the University. The first stars that formed that would later collapse into our galaxy.

Ted Simons: Are these original galaxy forming big bang stars or like the second or third generation?

Lawrence Krauss: In order of iron, they have probably gone through one generation, the current one is an upper limit but we're hoping to go back and look at maybe at least the second generation of stars, and maybe in our galaxy, if not the first generation. We need the devices that look at the spectrum of the stars to look for, for very small abundances of heavy elements and this is important because we want to understand how, how all this happens because the first stars to form were probably very different than ours now, if you have a bit of these heavy elements, they affected cooling in the star, and what's called the capacity, the ability of light to travel through a star, and turns out, if you don't have those elements, then you need a really big object to cool, so the biggest stars may have been 100 times the mass of the sun. And they burn in nothing, and in a few million years, but, we don't know for sure, so we're trying to figure out how things process because until we know that, we really won't know how your atoms came into you.

Ted Simons: Well, and we all really should, should know that.

Lawrence Krauss: I have always wanted to know where the atoms came from.

Ted Simons: You and me both. So basically, these grandpa stars, these really first generation stars, most of them were supernovas before anyone knew that they existed?

Lawrence Krauss: Yeah, the bigger the star, the quicker it burns, so a star ten times the mass of the sun burns 1,000 times faster, so the sun will last 10 billion years, one of those stars would only last 10 million years, and that's important because they had to recycle. You could not get stars like us, and planets, rocky planets around them until you had the heavy materials. So if it took 10 billion years for the first generations of stars to be around, we would not be having this conversation today.

Ted Simons: That is fascinating. Something else that's going on, I want to get information on, this idea of, of making a primordial soup out of smashing -- everyone wants to smash atoms together, and now we can make primordial soup?

Lawrence Krauss: It tastes very good.

Ted Simons: I'm sure it does.

Lawrence Krauss: It has been done, and what we're trying to do, we smash individual protons together, to look at their constituents, but one of the things that we want to do, is make, is smash a big object big enough together to contain many particles to see protons are made of particles, and one of the things we're trying to understand that may have happened in the first millionth of a second, is early on the only particles around were these, but at some point, it formed protons and neutrons. The way it happens is a process of melting, almost, and what we want to do, and with two protons, you cannot take a big enough region to get things hot enough to melt the protons and neutrons in a way you can measure. So, what they do at Brookhaven is smash -- they do, remember, anti-alchemy wanted to turn that into gold? Well, these contain so many protons and neutrons, that they can heat up a whole region to many trillions of degrees, the same temperature the University had when it was a millionth of a millionth of a second old. Over a large enough region that we can kind of create almost like a mini big bang. It's not a universe, but it's just like what our universe was like.

Ted Simons: I'm ready to hide under the desk because this sounds like you are creating another big bang, and you know what's going to break loose because some guys –

Lawrence Krauss: When two gold atoms meet, they produce a microscopically small region, which we can study, but the universe had all the mass that we can see. You are not going to create another big bang when you smash these together, and you are also not going to creating some that people are worried about, somehow creating these primordial black holes that would eat the whole Earth. One of the reasons that we know that does not happen, is in cosmic rays right now, we're being bombarded by lots of things, iron, all sorts of things coming from supernova, elsewhere in the galaxy coming with the high end energy as we produced at Brookhaven. The moon has been there for 4.5 billion years, the fact that it's there, and every year it's getting collisions from these nuclei, the fact that it's there tells us that we don't have to worry about producing the same collisions.

Ted Simons: Have, has it happened yet? Are we learning anything yet?

Lawrence Krauss: There has been tentative bits of data that have, have suggested exactly how corks break into protons but it has been sparse. What's happened is that Brookhaven geared up to have a much more -- in order to make these collide, it's hard to get two atoms to hit together. And, and create a collision, so, they cool these things down to close to absolute zero, and they use a lot of neat techniques to make sure that you got beams very narrow, and then you can get enough collisions to study it. That's the new development. They have been able to cool these things down, and we can -- and they are about to collide, and get as much data in a single run as we have gotten in the last 12 years.

Ted Simons: Wow. And we saw a photo of Brookhaven there. Is that, is that compared to the hedron, anything close?

Lawrence Krauss: No, it does not have as much energy per particle but because it can, it can produce a lot more particles, the amount of energy is comparable.

Ted Simons: Ok, and last thing, what is historical science?

Lawrence Krauss: Yeah, you know, there was recently a debate by a well-known creationist, Ken, the founder of this silly museum in Kentucky called the creation museum. And what he and others like to say, is that somehow, when we talk about our origins, it's different than when we talk about physics and chemistry in the laboratory because who was there? Who was there when, when life originated or when the Earth originated? But, it's a scam. It's a red herring. You know, science doesn't just tell a story. If it did just tell a story about the past, it would be historical. But, what it does is, is make, take that, that past data, whether it's obtained in the laboratory yesterday or from 5 billion years ago, and make predictions and observation that is we haven't yet done, which we can do tomorrow. It predicts the future, not the past, and even, even observations that you think are current, you can call historical science. And we can validate, let me give you an example. From evolution, one of the biggest things is that, is that the great apes have a different number of chromosomes, and we have 23, and they have 24. And now, if we have a common ancestor, at some point, what must have happened is the common ancestors chromosomes, two of them must have merged to form one to make, go from 24 to 23. What you can look for, chromosomes have at their end, things called telomeres, the ends of chromosomes and centromeres, so if two merged in the human code, there must be one chromosome that has, in its center, what looked like the telomeres of two of the great egg chromosomes, and at one quarter way across and three quarters of the way across, two versions of the middle ones, we can test it and find it, so, it's not looking in the past but looking in the present. But, it tells us what happened about the past. And so, to argue that evolutionary biology or astronomy are different than the chemistry and physics you do in the laboratory is to misunderstand science, science looks at observations not yet been done, whether it's evolutionary or cosmology or whatever, and those could be tested, and they allow us to then make new technology, whether it's new vaccines or new, new cars.

Ted Simons: So when those who, who promote historical science, say it's simply observation versus experiment, you can observe with these kinds of things but when you do it in a lab, that's not necessarily -- that becomes --

Lawrence Krauss: That's true, an experiment is different than an observation, in the laboratory you can twister the knobs and you have more control but that does not mean that you cannot do science. If you can falsify, you make an observation, and you say ok, well, I don't have complete control, but based on the observation, I can predict what's going to happen when I do an experiment like I do in the laboratory with the genes or, or I do an experiment by observing the sun. Then I am making a prediction that I can falsify. And if that prediction is true, it tells me that my observation is, is, basically, in the right direction. And, you know, even things that we see today, when we look at the sun, look at the sun now, and, and here in Phoenix, we get a lot of sun, and you look, it looks like an observation making what's happening today so it's not historical science. The sun is shining today. Turns out if you work out the physics of the sun, which we can test, we predict that it takes, you know how long it takes for the light to come from the center of the sun to the outside?

Ted Simons: No.

Ted Simons: Where it's emitted in the nuclear actions of the core, a million years. So when we're looking at the sun we're doing historical science because that was generated a million years ago and if the Earth was 6,000 years old like this guy thinks, the sun would not be shining as it is today. So you want to do an experiment to prove the sun, the world is older than 6,000 years? Look at the sun.

Ted Simons: So basically, what you are saying is science is observation and experiment.

Lawrence Krauss: And experiment, testing -- observation and prediction and testing with experiment. That's, that all goes together, and every one of the sciences, geology, biology, physics, chemistry, they are the same.

Ted Simons: And science includes hiding under your desk if that Asteroid gets too close.

Lawrence Krauss: Yeah, and you could do the prediction of if it hits you will discover that it hit.

Ted Simons: Good to see you again.

Lawrence Krauss: Thanks.

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