Krauss on Science

More from this show

Arizona State University Physicist Lawrence Krauss discusses the latest science news, including new information that may discredit a recent discovery of gravity waves.

Ted Simons: ASU physicist Lawrence Krauss joins us every month to discuss the latest science news, today it includes evidence of a hidden ocean between earth's core. Here now is our good friend Lawrence Krauss.

Lawrence Krauss: Good to be back on this cool day in Phoenix.

Ted Simons: Yeah, yeah. Okay. A huge ocean of water inside the earth?

Yeah. You know, there's a theme. I gotta step back. A theme to things I want to talk about today, which is how ideas are sometimes wrong and how we find out. It's really important to realize that science evolves and things that are reported or we think about can change. There's no reason to be embarrassed. That's a virtue of science, not a deficit. There's a lot of things that we are going to talk about where our ideas are changing. I want to talk about the fact you can check things and change your mind and test those things. So for several very important requirements we'll talk about our ideas are changing. This is one. We have talked about, and I'm sure you'll remember, we talked about the fact that the conventional wisdom is that most of the water on earth came from comets. If you calculate how many comets have hit the earth over the last 4.5 billion years there's enough to account for all the water on earth and this is reasonable because the earth formed when the region was about 1,000 degrees, not such a good temperature for having water. A little warmer than Phoenix is today. So it's interesting. We're talking about water before, water now. So it seemed that the earth might get its water later but there are various problems about that we talked about. We look to Mars to understand those issues. But what's really interesting is people thought that maybe actually the water on earth was always on earth. You mention how could it be on earth if it's 1,000 degrees? If it's trapped in rocks. What has been recently discovered by some tests in laboratories combined with measuring the earth itself is that certain minerals, something called ringwoodite, under high pressure actually can have water basically stored in the crystalline structure. It's a bluish material. Actually, up in March there was a diamond discovered with ringwoodite, which came from the lower mantle, transition zone, 300 to 400 miles below the earth surface, that it actually encompassed ringwoodite, and it had water in it. That was one sample. You can't say there's an ocean of water under there, but what's recently been done by some researchers is to do some experiments. What happens as that material goes down from that transition zone from upper mantle to lower mantle and with higher pressures and temperatures what they reasoned and can experimentally can be tested is that this material if it has water in it will melt and release the water. You say, okay, let's do a test. You look at the earth inside by using seismic waves, using sound, and seeing how fast it goes through the earth. What they have discovered is evidence that the rock in this transition zone is melting, which means it's giving up water. The amazing thing is there's so much potential water in that region if they are right, if there could be more water in there than water in all the oceans on earth.

Ted Simons: So we're not talking liquid, we're not talking ice, we're not talking vapor, we're talking basically crystal and water. Water that's trapped from crystals of a mineral.

Lawrence Krauss: Lawrence Krauss: We're talking basically crystal and water, water trapped in the crystals of a mineral. Under high pressure and temperature. When it gets too hot, the crystalline structure melts, the water is released, then it goes back into this transition zone and some people have said if this is true it's kind of like the earth is a sponge. Then what happens is eventually due to processes that water can be released from the crystalline structure, bubble up basically and fill up the oceans. If there's a huge amount stored there then the earth could be like a sponge. That would mean as the oceans decrease on the surface, more water would come up from the sponge and maintain the water level on earth. It's a fascinating possibility if it's true. It means more water underneath the earth surface than above.

Ted Simons: So --

Lawrence Krauss: That's the change I'm talking about. That's important. It means that conventional wisdom might be wrong but there's nothing wrong with it being wrong. In fact it's exciting and we can test it. This is the first test, and it's still tentative, that you can see melting, then one sample had water in it. We have do a lot more before this paradigm shift but that shift is great in science.

Lawrence Krauss: If true, what about plate tectonics? How much do we know what's going on underneath?

Lawrence Krauss: We're trying to learn how the earth works on the inside. Plate tectonics is on the surface. This is hundreds of miles below surface. There's obviously a relationship and some of this water will bubble up. All of that will change the dinamics and you have to plug that in. I should say one of the amazing things I learn when I was trying to figure out a new way to look for these particles many years ago is we actually don't even know for sure if the earth is cooling down or heating up because there's enough radioactivity on this -- just below the surface of the earth to account for all of the heat that's coming out of the earth. That's fine but if there was a little radioactivity in the interior it would be heating it up instead of cooling it down. So there's a tremendous amount we have to learn about our own planet and the fact that we don't know everything is great, and the fact that our ideas change is significant and it's going to be important not just for the earth but last time I was here we talked about life on other planets potentially trying to understand whether there's water on other rocky planets may be very important. If you can trap water in rocks, whether you have a habitable zone or not may be a little bit different. It's all related.

Ted Simons: Yes. Everyone is looking for water on different planets and such, and you just have to dig down a few hundred miles.

Lawrence Krauss: Later on the evolution of those planets when the temperature changes the water could come up.

Ted Simons: All right, something else we talked about the past that apparently is now getting the once-over twice here, is bicep gravity wave.

Ted Simons: This was supposed to be the gravity wave from the dawn of time.

Lawrence Krauss: I was so excited. Today in today's physical view letters the paper produced by that group that announced the discovery in march appeared and actually had a companion paper with it to try to explain its significance, but what has changed is it looks like these things, this was a signal of gravity waves from literally the beginning of time, now the observers, there's an image you can see son the screen.

Ted Simons: What are we looking at here?

Lawrence Krauss: We talked about it the day it was announced and yeah, today actually in today's physically there paper produced by that group that announced the discovery in March appeared and I actually had a paper with it to try and explain its significance but what has changed: it looked that this was a signal of gravity waves from literally the beginning of time. The universe was a billionth of a billionth of a billionth of a billionth of a second old. There an image of it. You're looking at a spaghetti-like signal in the lumps that we look at, hot spots and cold spots coming at us from the big bang which would be caused if a gravitational wave travels through that from the beginning of time through that surface to our eyes today. That would literally be an image of waves produced since the beginning of time. In fact every feature of the signal looked like we predicted it would look. I have often said if it walks like a duck and quacks like a duck it's probably a duck. It may be a duck but the problem is what was recognized almost immediately was you can get this signal or something that might be the Snarr another way. If there's dust in our galaxy, and the dust can be polarized, it can have charges that are pointed in different directions, it can scatter radiation and produce a signal that might look similar to that. Now, when the team published the results they said there can't be that much dust in the galaxy. Recently other experiments have looked for dust in our galaxy and suggest there may be more. Two different studies have been performed since that was done to say we have an you leased it and there could be enough dust to produce the entire bicep signal. The bicep team produced their paper but they still say based on their models they are convinced this is really a signal from the big bang. I have a bet going right now. I'm also convinced it's a signal at some level. It would be a conspiracy. The dust can produce enough of a signal that maybe mimics it but it would be such an unfortunate accident. Not only is the intensity right but the shape as a function of size looks identical and it would be an awful conspiracy of nature if this accidental dust looked like that. What's important many people say, look, we can't celebrate, we can't open those champagne bottles yet, and we will know. That's the other thing, we will know. Too often in media we report this wonderful discovery but then when other news comes out that says it may be wrong that doesn't make the news and it makes it seem like one day we discover one thing, another day another. This is how science progresses. You're not certain but we can check it. So if it's wrong, we'll all stop talking about it even though I love the idea for many, many reasons. If wrong we're back to ground zero.

Ted Simons: So the holy grail with a Noble Prize that we talked about earlier all on hold. They're on ICE right now.

Lawrence Krauss: It's on ICE. But they are standing by their guns. They say we still see something.

Ted Simons: Before we get on to this beautiful photograph of 10,000 galaxies here, the credibility of science and the credibility of astrophysicists and such does it take a hit with something like this?

Lawrence Krauss: There's been a lot of discussion, should they have made the discovery, made the announcement the way they did. The answer was that based on all the information at the time that they had available they could not see a way the dust could mimic the signal. This is in some sense new information. Other people are saying they should have waited for the new information to come along before they announced. It's easy to quarterback after the fact. I think they published a signal, they said what it was likely to be, there was a lot of hype surrounding it because it's incredibly exciting. As far as I'm concerned it's exciting if it demonstrates to the public that scientists who makes claims, we can test them and that's how science progresses. There's nothing wrong with that. Sometimes the credible should be enhanced. There's peer review. Any claim made is immediately tested -- the fact that for example evolution has been around for 150 years is evidence of the fact that it really works because if it doesn't other people would have cut it down.

Ted Simons: We have just a couple minutes left here. Something I don't think no else is going to question; this next photograph is gorgeous, taken from the Hubble telescope. What are we looking at?

Lawrence Krauss: This is the newest version of an image -- this is about 10,000 galaxies in a small region of sky, some going back to billion light-years away. What's new about this is the Hubble space telescope is taking images and visible light and infrared, but early stars produce ultraviolet light. A camera installed in the latest upgrade, the wide field camera, can detect ultraviolet radiation produced by early stars forming and they are very hot. Each frequency of light you look at somehow picks out galaxies formed at a different time. We looked at galaxies that were the earliest are billion light-years away, billion years old. But most of the stars in the universe probably formed between five and billion years ago and looking at the ultraviolet light allows us to look at it. This fills in a lot of the intermediate galaxies that are 5 to 10 billion light years away and as a colleague of mine would say, he helped produce this image, the sensitivity of this is like detecting a firefly on the moon.

Ted Simons: What we're seeing here that's red is what, farther away? Is closer blue?

Lawrence Krauss: In principle the bluer galaxies are earlier galaxies. A lot of the colors are put into the eye. In general the bluer galaxies are earlier galaxies.

Ted Simons: Before we get off this photo, some of the galaxies look out of shape what. Does that mean?

Lawrence Krauss: Well principle we're just learning but what we learned is galaxies form by what we think is the case, again, we may have a different program, but they form by cannibalizing other galaxies. Our milky way galaxy formed by caniballizing lumps and smaller galaxies that were rather irregular in early stages and as they evolved they get this nice spiral shape. That is until they collide with another galaxy and they get messed up and that will happen to our own galaxy in 5 billion years when we collide with Andromeda then we won't be a spiral anymore. For a while we'll be elliptical, then spherical.

Ted Simons: When will that happen again?

Lawrence Krauss: 5 billion years. You don't have to worry about the water. It will all be gone.

Ted Simons: The Hubble telescope is amazing.

Lawrence Krauss: It is inspiring. I say it all the time. If you think science takes out our, spirituality, it doesn't. Look at a Hubble space telescope image and tell me you're not inspired about the universe.

Ted Simons: How does the human mind wrap itself around the concept of 11 billion light-years away?

Lawrence Krauss: It's hard. But that's what science does. It expands the way we think. If we didn't keep exploring the universe we would just be bio-pic. Science makes us uncomfortable in a good way. It forces us to get out of our comfort zone and start thinking about times, distances that we can't imagine and there are lots of ways to do it. The more we learn about the universe the more surprised we are and at the same time the more open minded we are. We learn the way things are here is not the way they are everywhere necessarily.

Ted Simons: Thank you for our monthly discussion for making us uncomfortable yet one more time.

Lawrence Krauss:Physicist, Arizona State University;

Central Arizona Project Water

A graphic for the Arizona PBS news show,
airs April 27

New and local

Illustration of columns of a capitol building with text reading: Arizona PBS AZ Votes 2024

Arizona PBS presents candidate debates

Earth Day Challenge graphic with the Arizona PBS logo and an illustration of the earth

Help us meet the Earth Day Challenge!

Graphic for the AZPBS kids LEARN! Writing Contest with a child sitting in a chair writing on a table and text reading: The Ultimate Field Trip
May 12

Submit your entry for the 2024 Writing Contest

Subscribe to Arizona PBS Newsletters

STAY in touch

Subscribe to Arizona PBS Newsletters: