Planetary Radio: Space Exploration, Astronomy and Science - Cosmology: Five Big Things You Need to Know

Episode Date: April 9, 2007

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5 Things You Learn in the Heavens Cosmology, this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan. You'll find it on the cover of Astronomy magazine. Cosmology, five things you need to know. Writer Liz Kruse asked a herd of cosmologists to tell her the questions they get asked by the public. She then distilled the responses down to the big five. The astrophysics grad student will answer them for us today, right after a few headlines

and a visit by Emily Lakdawalla. And out at the other end of our half hour, Bruce Betts waits to deliver his review of the night sky and another cosmic trivia question. You'll also learn about both axial tilt and a heck of a tilted axe, if you stick around. Ho-hum, another space tourist. if you stick around. Ho-hum, another space tourist. Charles Simonier is the latest to fork over $25 million for a ride to the International Space Station. The Microsoft billionaire's Soyuz should have reached the ISS

by the time you hear this. He and a couple of cosmonauts will join the current crew for a total of six souls in orbit. That will last till the crew rotation back to Terra Firma on April 20. Remember Hayabusa? The troubled spacecraft is now set to begin its return to Earth, hopefully with at least a few bits of collected asteroid safely stored away. The Japanese space agency will fire up the ion engine in mid-April.

You can read more about Hayabusa in Emily's blog at planetary.org. And Emily is ready to clarify some of the recent news from Mars in this week's Q&A segment. I'll be right back with Liz Kruse. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, If Mars has no water, how come there's frost on some of the pictures? Members of the public are understandably confused about whether there is water on Mars. It seems that at least once a year, a major announcement is made by an orbiting or landed Mars spacecraft team

about some important water-related discovery. All too often, it sounds like they are announcing the discovery of water on Mars. In fact, the current presence of water on Mars is not news. You can even see water on Mars through a backyard telescope, frozen solid in the north and south polar caps. There's enough water frozen in Mars' north polar cap to cover the whole planet to a depth of two meters. There's water ice in the air, too, making wispy white clouds just like the ones that form at high altitudes in Earth's skies. And in winter, the water ice in the air can condense onto the ground,

forming a frost just like on Earth. So what is news about water on Mars? Stay tuned to Planetary Radio to find out. What came before the Big Bang? What is the expanding universe expanding into? And if all the other galaxies are flying away from us, doesn't that mean we're in the center of the universe? It was questions like these that made us decide it was time for one of our infrequent looks at that universe-spanning field called cosmology.

Liz Kruze provides an illustrated overview of these and other big questions in the May issue of Astronomy Magazine. The former editor- turned Iowa State astrophysics graduate student, put together a compact article called Cosmology, Five Things You Need to Know. Liz Kruse, thanks very much for joining us on Planetary Radio. Thank you for having me. Let me ask you about your article, which appears to be the lead article in the current, the May issue of Astronomy magazine. Did they come to you and say, hey, Liz, we want you to write about these five questions?

Or did you come up with this? And if you did, how in the world did you narrow it down to just five? Well, while I was an editor for Astronomy, I was thinking this would be a really great topic because there's so many questions out there and so many hard things to grasp in cosmology. So I kind of came up with the idea of Cosmology 101, just getting some of the basics down, and it turned into more of questions or difficult concepts to grasp for most people. And what I did is I ended up emailing about 30 cosmologists and astrophysicists

to see what questions they get from the public, what misconceptions they're encountered with most often. And with the lists that I got from them, just pretty much tallied them up and figured out how many questions I could fit into about six pages and wrote answers for about five of them. Did you find, as you talked to these cosmologists, that they were happy to talk to you, knowing that this was going to go into a popular magazine and help explain some of these mysteries or what we do know about these mysteries?

There was definitely a mix. we do know about these mysteries? There was definitely a mix. Some people were really excited about it and would write back an email with their own short answers that they give to people when they have these questions. And some people would just give me a really quick response with their top five, the questions that they get. And that was fine because all I really needed was the questions.

It was varied, but it worked. Well, so this basically then was you arrived at by consensus after talking to these 30 or so cosmologists. Mm-hmm, yeah. All right, well, let's get right into them. The first one I'm guessing that we don't have to spend too much time on because, frankly, we could spend the whole period we've got and more on any one of these. But this is one that actually I bet a lot of people in our audience have heard

maybe the best analogy for, the most common one at least, and that's if distant galaxies are all moving away from us, doesn't that mean we're at the center of the universe? And you point out in the article that very frequently people then take out a balloon. Yeah. The balloon analogy, as I do state in the article, is probably not the best because we live in a three-dimensional world, or really you could say four dimensions if you want to factor in time, but the balloon analogy only wants to take into

account two dimensions, just the surface of the balloon. In our three-dimensional world, it's quite difficult to just look at the surface of the balloon and not our three-dimensional world, it's quite difficult to just look at the surface of the balloon and not focus on what's at the center. So everyone asks, what's at the center of the universe, or at the balloon, thinking it's the center of the universe. But again, as I do state in the article, I think the raisin bread idea is a wonderful way to show it. Right. Every raisin is moving away from every other raisin where the raisins aren't changing, but what they're embedded in does change.

And I think that's a great lead-in to the second group of questions, which hopefully we can spend a couple more minutes on. Number two, what is the expanding universe expanding into? And I'm going to combine it with number three, what's outside the universe? You know, if it is an expanding universe, there must be something it's expanding into, right? Actually, no. This, again, I'd almost jump ahead and almost tie it into parts of the other questions, too. This was part of the difficulty in writing this, is I almost would start writing just a full-out answer,

and it was hard to break it up into all these separate questions and answers because they're all so intertwined. But the main thing is just it's not really, well, the universe isn't really expanding into anything because the universe is the universe. It's just all the stuff that's out there. So you don't really have an outside to the universe. We may have an observable universe, which is really what we can see.

This goes into that other question of what's outside the universe. Light travels at a particular speed, and when you factor that in with the age of the universe, which is 13.7 billion years, there's a certain distance that we can observe, and that's known as our observable universe. And that gets confused quite often with the term universe. And a lot of people, including scientists and journalists and everyone else, will use the word universe

when they mean observable universe. And I know that's something that I personally did until I had it defined. Just that causes confusion because you think the universe, what's outside of it. But really, the observable universe inside of whatever the rest of the universe is, which is probably just more of the same, because we're only seeing a certain part of the universe is, which is probably just more of the same, because we're only seeing a certain part of the universe. And I've just used the word universe many times to get probably circular reasoning. But basically it's this thought that as the universe expands,

it's really the space that contains the universe is expanding along with everything in it. Exactly. It's that fabric of space that's expanding itself. It's not expanding into other space because there is no other space there. Now, without wanting to get into a lot of detail on this, it was maybe just a year ago we had astrophysicist Lisa Randall on, and she talked a little bit about this possibility of multiple universes, or the multiverse, as some people call it. But that may not make much difference in terms of our universe? Yeah, I don't know a whole lot about the multiverse theory, but I think that we couldn't communicate with another universe.

And so if there are multiple universes out there, there I think that we couldn't communicate with another universe. And so if there are multiple universes out there, there's no way we could transfer signals from ours to a different universe. And of course, nobody has any proof that there is any such thing at this point. Liz Kruse is the author of Cosmology, Five Things You Need to Know, in the May issue of Astronomy Magazine. We'll explore more mysteries of the universe with her when Planetary Radio continues. Hey, hey, Bill Nye the Science Guy here. I hope you're enjoying Planetary Radio. We put a lot of work into this show and all our other great Planetary Society projects. I've been a member since the disco era.

Now I'm the Society's Vice President. And you may well ask, why do we go to all this trouble? Simple. We believe in the PB&J, the passion, beauty, and joy of space exploration. You probably do, too, or you wouldn't be listening. Of course, you can do more than just listen. You can become part of the action, helping us fly solar sails, discover new planets, and search for extraterrestrial intelligence and life elsewhere in the universe.

Here's how to find out more. You can learn more about the Planetary Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt. Members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. Liz Kruse is a graduate student in the astronomy department at Iowa State.

Before she left astronomy magazine, she wrote Cosmology, Five Things You Need to Know. The piece is in the new May edition. Let's go on to the next question, and that takes it back to the beginning of our universe. What kind of explosion was the Big Bang? I love this question because the question itself shows that we really, it's just a huge misconception because the Big Bang was not really an explosion. But by naming it the Big Bang, which was just a misnomer and really just kind of a joke by the steady state theorists,

the opposing theory to the Big Bang, saying that it's the Big Bang implies it was just, well, an explosion. And when we think of an explosion or a bang, we of course think of fireworks or chemical reaction or some sort of very loud, bright type of explosion. And that's not what the beginning of the universe was. It was more of just an unfolding of space and time and everything in it. It's just a bad name, an explosion. You've got to be careful about the jokes you make because they may outlive you. Exactly, exactly.

There's a great illustration, my favorite illustration in the article, is this two-page one that shows it's called Big Events Since the Big Bang. And it's a really nicely done piece. I don't know who did it, but it basically traces things back to, well, as far back as we can go, which is not quite back to the very beginning. There's definitely a limit as far as physics can reach. We can only experimentally reach a certain point, and then from there use theory to get to another point, certain point and then from there use theory to get to another point and then we're completely lost because our our computers our math formulas our experiments just there's no way we can get

all the way to that final moment we've been able to unify the electromagnetic electromagnetic force and the weak force, but the hope is to unify that with the strong nuclear force. And then we still have gravity, which does not fit in at all with these quantum forces, electromagnetism, the weak force and the strong force. It's going to take fitting those together to finally be able to figure out exactly those first 10 to the negative 43 seconds right after the Big Bang. And it's going to take something like supersymmetry or string theory to really probe that time. And we would refer people back to our interview with Lisa Randall done a year ago if you want to hear more about supersymmetry and string theory. And you actually have a picture of a piece of the LHC, the Large Hadron Collider.

Now, I guess, finishing touches being put on it as it's assembled there in Europe, which may help us to reach back a little bit further and understand what's going on. Yeah. The LHC is, last I've heard, supposed to be up and running by November of this year. So that's pretty close, pretty exciting. And that could possibly detect a supersymmetric particle, which could possibly rule out, rule in, that detects a supersymmetric particle as a possibility of giving further proof for dark matter. If it does not detect the supersymmetric particle,

then we may be ruling out something. Let me throw the last of the questions at you here, and I should admit that I'm taking these somewhat out of order. What came before the Big Bang? This one, we have no idea. This is where philosophy can come in. And maybe even theology. Exactly, exactly.

We cannot scientifically get back to the point of the Big Bang and look further into the past. There's just no way that scientists can do that. So we don't have any direct evidence for it. And this is kind of where the mind can go free and each person can, I guess, kind of come up with their own reasoning or whatever came before it. But scientists really, we have no idea. Let me ask you how you got into this. I mean, first as a writer or a contributing editor to Astronomy magazine,

and later as a grad student in a program there at Iowa State. Obviously, this holds some fascination for you. Yeah. Years and years ago, so I guess when I was probably in middle school, I've just always been in love with astronomy. And what drew me to physics is just really understanding how things work. Cosmology makes you understand how the universe works and how it's put together. And that's what really draws me. It's a fascinating science. You

really get to learn about the place around you. Liz, I'm just wondering, I mean, you used to be the book reviewer at Astronomy magazine and, in fact, wrote sort of what? Was it the best 18 books of the year or something? Yeah, it was. In December 2006, I wrote up basically an overview of the best 18 books of the year. Well, so you obviously have read pretty widely in this area, astronomy and specifically in cosmology. Who do you look to?

I mean, who do you most, who did you get the most out of, both in terms of enjoyment and information, when you want to read about this universe we live in? Probably my favorite book, actually, wasn't included in that article because it was written about 15, 20 years ago, but it was Dennis Overby, Lonely Hearts of the Cosmos, fabulous book about the lives of the cosmologists, seeing a completely human side.

And on that note, I can't remember for the life of me who it was, but Moondust, which I know came out about a year ago, it was the same thing, or two years ago, but looking at the lives of those involved in the Apollo program, just seeing the human side of science really interests me personally. As it does us on this radio show. Liz, we are out of time. We will simply recommend your article, as I said, in the current issue of Astronomy Magazine. That's the May 2007 issue.

It should now be on the newsstands as you hear this show. Cosmology, Five Things You Need to Know. Its author, Liz Kruse, former contributing editor to Astronomy Magazine, currently in the astrophysics program as a graduate student at Iowa State. And Liz, thank you very much once again for joining

us on Planetary Radio. Thank you. We'll return in a minute or so with a topic somewhat smaller in scope but still as big as the night sky. And that'll be this week's edition of What's Up with Bruce Betts, the Director of Projects for the Planetary Society, right after this return visit from Emily. I'm Emily Lakdawalla, back with Q&A.

There is plenty of water on Mars today in its polar caps, its atmosphere, and even buried underground. So why are so many missions at Mars looking for water? What those missions are looking for is evidence that liquid, not solid, water was ever stable on the surface as it is on Earth today. There are lots of hints that Mars could once have been warm enough with a thick enough atmosphere to support the long-term presence of liquid water. But so far, there is no absolutely conclusive evidence that Mars' climate was ever much different from the cold, dry, dusty environment it suffers today.

Despite the provocative discoveries made by orbiters and rovers, plenty of Mars scientists doubt the hypothesis of a warm, wet Mars. Why is this important? Because if there was liquid water on Mars for a long time, there could have been Earth-like life as well. And perhaps that life could yet survive in deeply buried rocks that still retain enough heat for water to percolate through them as a liquid. But if Mars was never warm enough for liquid water to sit around on the surface, then the evolution of Mars life appears pretty unlikely.

So the key question in Mars exploration is not, is there water on Mars? But instead, was liquid water ever stable on Mars? That's what we're trying to figure out. Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. All right, so here he is, Bruce Batts, the director of projects for the Planetary Society,

ready to tell us about the night sky and bring us a quiz, a quiz question or the answer to a quiz from two weeks ago that some of you might have noticed, in fact, you did notice, was a repeat. Well, you know, again, I do it as a test. Uh-huh. Yeah, go on. Tell us. Would you believe people pass because they recognize that it's a past trivia question? All right.

You just have years of trivia, so it's also, I guess, getting challenging. But I'm going to try to give you something new today. You're right. Either that or I'll just do everything as repeats. But, you know, repetition makes you learn. Five and a half years of trivia questions. That's what we've got. Wow.

All right, well, what's in the night sky? In the night sky? I'm glad you asked, because, funny, I was going to tell you. Venus dominates the early evening, looking like the brightest star in the sky in the west. If you're looking to check something out in the early evening, that would be the easy thing. We also have Saturn up, though. Saturn up in the evening sky. It will be high in the south or north or just overhead, depending on where you live on the earth.

But it will be high in the sky. It will look kind of yellowish. depending on where you live on the Earth, but it will be high in the sky to look kind of yellowish. And if you're someone who's had trouble figuring out which one of those things is Saturn, go out there on April 24th, and it will be right next to the moon. So the bright star-like object right next to the moon on April 24th is Saturn. Will you remind us of that next week, sir? I will. I'm just trying to get it in people's heads early,

and depending on when they listen to these, get it out there. And I'll try to remind you. Yeah, that'll be Saturn. And if you're up in the middle of the night, you've got Jupiter rising in the middle of the night over there in the east looking like a really bright star. It'll be really high up pre-dawn. And also Mars still hanging out looking dim and reddish in the pre-dawn off there in the eastern sky. And that's kind of what's going on in the sky. All right.

Let's go on to random space. That was operatic. Why, thank you. I think. What a shame that we're on the phone. Why, you wanted to see me do that? No, I just think that to get the full high-fidelity tonal quality, you may have to repeat that in person next time.

All right, well, we'll do that. We'll do a full-blown high-frequency squeal. We've got to get a symphony to back it sometime, too. A symphony? Yeah. Can we do that? I have no. We can't.

Okay. Maybe we can fake it. I'll work on it. All right, random space facts, some basic star knowledge. First of all, the Earth's star, the sun, sadly, just very average in just about anything you pick from size to color. And color correlates to temperature, which brings us to the rest of the random space facts. correlates to temperature, which brings us to the rest of the random space facts. It's yellowish with a surface temperature in the 5,000 kelvins, close to 6,000. And if you get

hotter stars, like one we'll talk about in just a little bit, then they go bluish, like up at surface temperatures of 10,000 kelvins. And if you get cooler stars, then they're reddish with temperatures down in the 3,000, 4,000dish with temperatures down in the 3,000, 4,000 range, 2,000, 3,000, 4,000. And we have this whole spectrum of different stars. And if you actually stare at the night sky, as I encourage you to do, you'll notice that some stars are much redder and some much bluer, and that ties to their surface temperature.

For example, check out some of the bright stars in Orion, which is still, for the northern hemisphere, given a very nice viewing in the evening sky. And you'll see some looking very reddish and some very bluish, tied to the surface temperature and how blackbody radiation works. That's especially fascinating. And, you know, we use this in the television business in my other life because we use these color temperatures to make sure that things look the way they should when people watch them on their plasma screen.

And sure enough, up there around, what, 5,600 degrees Kelvin, that's what we say, oh, that's sunlight. Wow. You actually know a lot of stuff, too. I hit you with a random space fact, actually. You hit me with a random TV fact. Random video fact, yeah. That really is near and dear to my heart. So that's cool.

Shall we go on to the trivia contest? Yeah. Cool. We asked you, what planet in our solar system has the smallest axial tilt? So the tilt of the axis relative to its orbit going around the sun, the Earth, of course, around 23.5 degrees, giving us our seasons. How did we do, Matt? Oh, we got the most wonderful collection of answers.

And, of course, you know, it's always a shame we can only award one T-shirt per week because we did get some really entertaining ones. Kevin Heck wrote in to say that Mercury should be really proud to stand upright, nothing like the many other drunken sailors in our solar system, because Mercury is pretty close to straight up at attention. What, an axial tilt of about 0.01 degrees? Yes, yes, very tiny, basically, sir. We also heard from Edward, Edward Lupin.

He's the vice president of a company called Cafe Lisa, who is, I hope, now going to send us a nice package of their coffee. He says it's a good thing the Mercury stands up that straight, because if you were drinking our coffee there, it would be less likely to spill out of the cup. But here's the best one, okay? Still not the winner, torsten zimmer who uh worms his way into getting his name mentioned pretty frequently on the show torsten has a photo and we really folks all we can do is describe it we'll put the link on the website you got to go to planetary.org

slash radio and you will see not an axial tilt, but a tilted axe, a memorial. It's like 20 feet high, and it is quite literally a tilted axe. And I'm guessing this is not a memorial to Mercury. No, it's not. I don't believe so. It's kind of like Paul Bunyan left it someplace. I don't even remember what it's about, but we'll put the link up, and you've got to see it, folks. But our winner was Daniel Cohn.

Daniel Cohn of, you know what, it doesn't say here, so we're going to have to write back to Daniel and find out where he hails from. But it was Daniel who got chosen randomly, and we do mean random, by the way. People question this. Random.org has a random number generator, and we use that to pick these out. Not only did Dan win, but he said this really nice thing. Can I read it to you? Please, please do.

Please accept my warmest regards and sincere thanks for producing this show. It's amazing to me that a program about cold, harsh places that are so far away, I will never get to see them, can give me such a warm feeling. Oh. Do you think he meant Pasadena? Maybe, maybe, but not today. Are you related to him? No.

Oh, okay. This is accent. It is. It really is. Do you have a new one for us? I do. I have a new one, which is kind of on the simpler side this time around. The very blue and very bright, brightest literal star in the sky other than the sun, Sirius, the dog star.

What constellation is Sirius in? Give us the nice Latin name of the constellation that Sirius is in. Go to planetary.org slash radio to find out how to get us your answer and compete for the glorious Planetary Radio t-shirt. You've got until Monday, the 16th of April, Monday, 416, at 2 p.m. Pacific, to get us your entry. That's it. Hey, that was fun. It could only have been more fun if we'd been together in person. It's true.

Well, hopefully next time, then. You bet. And in the meantime, everyone, go out there, look up at the night sky, and think about sea lions. Thank you, and good night. Go out there, look up at the night sky, and think about sea lions. Thank you, and good night. I love how he gets that ball up on his nose, and it just stays there. Here's a little piece of herring here.

Hang on. That's Bruce Betts, the director of projects for the Planetary Society, and he joins us every week here for What's Up. By the way, that book about the Apollo program Liz Kruse mentioned during our conversation, By the way, that book about the Apollo program Liz Kruse mentioned during our conversation, Moondust, In Search of the Men Who Fell to Earth, was written by Andrew Smith. We ought to talk to him someday. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week, everyone. Thank you.