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Telescopes Probe Birth Of Stars And The Universe

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Telescopes Probe Birth Of Stars And The Universe


Telescopes Probe Birth Of Stars And The Universe

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JOE PALCA, host:

From NPR News, this is SCIENCE FRIDAY. I'm Joe Palca.

If you've ever looked up in the night sky and traced the figure of Orion, you've probably seen the Orion nebula 2. It's visible even to the naked eye as part of the sword hanging from Orion's belt.

The Orion nebula is a fertile star forming region and it's one of the places a new space telescope will be studying. The telescope is called Herschel. It was launched last month by the European Space Agency. Herschel's goal isn't to take pictures that you'll ooh and ah over like the ones Hubble Space Telescope sends back. It's going to study light from the nebula beyond the visible spectrum to give us some clues to how stars are born.

Herschel launched together with another new telescope, Planck, which is going to look even farther back at the remnants of radiation from the glowing newly formed universe over 13 billion years ago.

Joining me to talk about these two telescopes are my guests. Paul Goldsmith is the project scientist for the NASA Herschel project and chief technologist for the astronomy and physics director at the Jet Propulsion Laboratory in Pasadena, California. He joins us from JPL.

Welcome to SCIENCE FRIDAY, Dr. Goldsmith.

Dr. PAUL GOLDSMITH (Project Scientist, NASA Herschel Project): Hi, Joe. Pleasure to be here.

PALCA: And Charles Lawrence is the project scientist for the U.S. Planck project and the principal scientist in the astrophysics division at the Jet Propulsion Laboratory in Pasadena, California. He's also at JPL.

Welcome to SCIENCE FRIDAY, Dr. Lawrence.

Dr. CHARLES LAWRENCE (Project Scientist, NASA Planck Project): Thank you. I'm glad to be here.

PALCA: Good. Now, I'd like to start with you, Dr. Lawrence. And maybe just to explain: NASA is a partner in these projects, but officially, we give these to ESA, the European Space Agency? Or have I got it wrong?

Dr. LAWRENCE: The European Space Agency is the lead agency…

PALCA: Right.

Dr. LAWRENCE: …for both of these missions.

PALCA: Right.

Dr. LAWRENCE: And NASA and the U.S. have made significant and enabling contributions to both of them.

PALCA: Sure. I got it. So tell us a little bit about Planck. What's it going to be looking at?

Dr. LAWRENCE: Planck will measure what we call the cosmic microwave background, the oldest electromagnetic radiation or light in the universe. It was emitted, as you mentioned, 13.4 billion years ago and it shows us directly what the universe was like just 380 years after the Big Bang. Not the movie, not the historical novel, but the original photons from the dawn of time.

PALCA: Wow. And those - there have been other missions, I mean, that have looked at this - COBE, I seemed recall, and some of these others. But what's Planck got that these guys don't got?

Dr. LAWRENCE: Yes. Planck is the third generation space mission to measure the cosmic microwave background. It will give us the clearest and sharpest baby pictures of the universe that have ever been made. And the reason for those clearer and sharper pictures is a lot of state-of-the-art technology. We're putting the most sensitive microwave and millimeter wave detectors that have ever been put into space.

PALCA: Cool. I want to remind people, by the way, that they're welcome to join this conversation by dialing 1-800-989-8255. That's 1-800-989-TALK.

And maybe I can turn to you now, Dr. Goldsmith, and say, tell us a little about Herschel. What its goal here? I mentioned it's looking for baby stars.

Dr. GOLDSMITH: Yes. Well, star formation is one of the overarching themes for Herschel. And to do that, we want - we're looking in a region of the spectrum, that is at wavelengths that you really can't observe from the Earth because - in particular water vapor and the Earth's atmosphere blocks radiation coming in at wavelengths between short radio waves and infrared radiation and heat.

And so, you have to get above the Earth's atmosphere, and that's what Herschel will do. In addition, it has a three-and-a-half-meter diameter telescope. That's the largest monolithic telescope yet launched for astronomy. So the combination of that large telescope, also with highly sensitive new detectors, will let us see what's going on in these star formation regions at wavelengths that just never could be looked at before.

PALCA: Now, one of the things that I find very interesting about these missions is that they take a very different approach than previous Earth-based, or telescopes, that launched from Earth. And that is that they're going to this thing called the Lagrange points, or one of the Lagrange points. Can you explain what the advantages of those are? Because that's like - those are millions of miles from Earth, right?

Dr. LAWRENCE: Right. Let me locate this thought. We are at the second Lagrange point - or we will be when we get there - at the second Lagrange point of the Sun-Earth system. Start at the Sun, take a line through the Earth and continue that line for about one and a half million kilometers, four times further from the Earth than the moon. So by solar system standards, not far from the Earth...

PALCA: Mm-hmm.

Dr. LAWRENCE: ...but four times as far from the Earth as the moon. And we'll stay on that line - both Herschel and Planck will stay on that sun-Earth L2 line. For both of them, the advantages are that we are far enough from the Earth that the heat of the Earth doesn't affect us. But we're also in a place where it's easy to communicate with the Earth.

And finally, especially in the case of Planck, the sun, the Earth and the moon are all off in the same direction, and we can shield from all of them. We don't want radiation from the sun, the Earth or the moon to be getting into our instruments at all. So that's a beautiful place to be.

PALCA: Right. And I guess, this goes to the debate about where to put your space telescope buck, because one of the - one of the great things about the Hubble Space Telescope was that it got serviced a couple of times and it's lasted - well, I guess - what, it's number of decades now, whereas these guys, if they break, it's finished, right?

Dr. LAWRENCE: That's right. But...

PALCA: So, you get a good spot to observe, and this is the trade-off people have been debating.

Dr. LAWRENCE: That's right. You get an excellent spot to observe, wonderful conditions. You can observe all the time, you're not - the Earth doesn't get in the way. It's true that you can't do the servicing. But servicing is expensive.

Dr. GOLDSMITH: One advantage - it's really more of an advantage - in order to really take advantage of the sensitivity of the detectors that now exist, the whole telescopes - this includes - Herschel, for example, three and a half meters in diameter, has to be very cold, in this case 70 degrees above absolute zero. And it's extremely difficult to get a telescope to be that cold if it's anywhere near the Earth.

So, while it's true, we do give up the servicing. We gain so enormously in sensitivity that it's a trade-off that's increasingly becoming -driving missions to go to the L2 point. For example, the James Web Space Telescope, the - in a sense, the successor to Hubble, will also be heading out in that direction in another few years.

PALCA: I see. We have a question now from Second Life from Laura Pelcher, I guess, who says: Why does a telescope have to be in any particular place to see old radiation, as opposed to other kinds of radiation? I mean, why do you want to go out - what's wrong with doing that from Earth, I guess? Is that Dr. Goldsmith or - no, Dr. Lawrence, maybe.


PALCA: That's your question.

Dr. LAWRENCE: Yeah. In fact, we could - and we do see this old radiation from Earth. The advantage of being at L2 or somewhere far away from Earth is that we don't see any radiation from the Earth. And L2 is particularly good because we can block the Earth and the sun and the moon all at the same time. So, it's what we avoid that's important about L2.

But, yes, you can see the cosmic microwave background from anywhere. In fact, just a fun fact about the cosmic microwave background, there are more photons in the universe from - in the cosmic microwave background than anything else. Every second, every square centimeter, 10 trillion photons of the cosmic microwave background pass through that square centimeter. So, just think how many photons are passing though our heads as we talk.


(Soundbite of laughter)

That's great. Well, let's take a call now and go to Shawn(ph) in Oklahoma City. Shawn, welcome to SCIENCE FRIDAY. You're on the air.

SHAWN (Caller): Thank you. And I enjoy your show especially on Friday, the SCIENCE FRIDAY. I really appreciate you taking my call. I have a -just kind of a general question. What are the - I mean, what are you guys trying to find with telescopes? What are we looking for?

PALCA: That is pretty general. Well, we've gotten a couple of points along that. But let me ask you, Dr. Goldsmith. When we get the data back from this telescope, are we going to - I mean, I said it wasn't going to be ooh and ah pretty pictures like from Hubble. But will there be these moments where the public will be able to say, oh, now I get it or is this going to be more fodder for scientists who are going to be, you know, chewing through this in trying to figure out about early star formation?

Dr. GOLDSMITH: That's a good question. In some ways, the data that comes back will be fairly easily understood. For example, one of the key ways in which Herschel will probe star formation is to look for signals from water. Now, that may sound surprising, but these clouds of gas and dust, out of which new stars form, are known to have water molecules, H20.

PALCA: Mm-hmm.

Dr. GOLDSMITH: It's actually the same water molecules that block our view from the Earth's surface that make us have to go into space. But out there in these clouds, water is a very important molecule because its radiation lets these clouds collapse and form new stars. So there will be signals, and there will be some images, perhaps not as quite as huge as the ones from Hubble, that will tell astronomers how much water there is in these clouds, what is - how the material is moving around, is it actually collapsing inwards to form new stars.

And I think some of the data, something that people in general will be able to appreciate and learn something about how stars, and your planetary systems that get formed with the stars, are coming into being.

PALCA: Right. And Dr. Lawrence, as I understand it, there is going to be a lot of computational oomph that's going to be needed to make sense of some of the data coming back from Planck about these early temperatures from the early universe.

Dr. LAWRENCE: That's right. Yes. We will take data and we'll observe the whole sky twice in a year. We expect the mission to last for two years. And in order to pull out the signal of the cosmic microwave background, we have to separate the radiation from all of the other radiation from the rest of the universe that is between us and the background.

So, we have to, in a sense, remove the bugs on the windshield. We also have to remove a lot of subtle effects from the instruments. We have to understand our signal at a level of about one part in 100 million, one in 10 to the eighth, of the total signal that comes into the instruments. And doing that over the whole sky, simultaneously with all of the interesting effects of how we scan the sky built-in, is a big computational job.

In the U.S., we have a partnership between DOE and NASA. And we'll be using for our biggest computational jobs the super computer at the National Energy Research Scientific Computing Center, part of the DOE supercomputing infrastructure. So that's a good thing. But we'll be calculating a lot.

PALCA: We're talking with...

Dr. LAWRENCE: I'd like to also...

PALCA: Oh, go ahead.

Dr. LAWRENCE: Sorry. Go ahead.

PALCA: Okay. I was just going to say - I have to do a brief introduction to - that we're talking with Doctors Paul Goldsmith and Charles Lawrence at Jet Propulsion Laboratory about two new missions going to outer space to observe the universe.

I'm Joe Palca and this is SCIENCE FRIDAY.

Sorry, go back to what you were saying. I had to clue people in there for a second.

Dr. LAWRENCE: Your caller asked a good question about what we would be looking for. I'd like to talk a little bit about why the cosmic microwave background is so important. We said that it's the radiation from the very early universe, the baby picture of the universe. The reason it's so important is because it's the end result of the early processes after the Big Bang.

And it's also the starting point for the development of structure in the universe after that, the formation of stars and galaxies. So it's right at that intermediate stage, and it's very, very simple. That may sound paradoxical, that something that is difficult to observe takes a tremendous technology and all this computation is very simple.

But the universe, 380,000 years after the Big Bang, was made of hydrogen, a little bit of helium, a tiny bit if lithium, and a kind of matter that we call dark matter that's of a different sort entirely. And that's it. There were no heavy atoms, no carbon, no oxygen, no nitrogen, nothing to make people or aliens or space craft or anything out of. It was very simple. No chemistry.

The temperature was about 3,000 degrees Kelvin. That's a little bit hotter than a candle flame, but think of a candle flame. So the entire universe was ionized, it was a candle flame at 3,000 Kelvin. And the density was pretty low, much higher density than it is now. So we understand all of the physics of that. We can work out what we would observe, what - how that plasma would behave, 380,000 years after the Big Bang in terms of how much mass is there.

How much mass of a kind we're made out of. What's the size of the universe, what's the age of the universe, all of these factors. We can calculate what it will look like. Then we go and measure it, we compare with the calculations, and it tells us more than any other single thing we can observe about the contents and the geometry of the universe. So...

PALCA: So you think this will help give - well, I was just going to say, do you think this will give us a little bit more insight into this stuff called dark matter, which is certainly something people are curious about now? I mean, dark energy, I'm sorry.

Dr. LAWRENCE: Well, yes. So, dark energy is something that we know exists. We have given a name to it. We don't know what it is.

PALCA: Mm-hmm.

Dr. LAWRENCE: Planck will tell us the starting conditions for the development of the universe. The effects of dark energy are seen later in the way that it affects the rate of expansion of the universe. So Planck will tell us very accurately the starting point for that expansion. And that will help a lot in refining our understanding of the effects of dark energy.

There's also another way in which we may be able to watch the effects of dark energy later on because the cosmic background radiation is traveling to us past all the other mass intervening. And the effects of that mass on the cosmic background can tell us about the development of that mass at more recent times than all the way back where the cosmic background comes from.

PALCA: Right. Well, we'll have to leave it there. But thank you very much for joining us today. That was Dr. Paul - Charles Lawrence. He's the project scientist for the U.S. Planck Project and a principal scientist at the Astrophysics division at the Jet Propulsion Laboratory in Pasadena, California.

Along with him, we were joined by Paul Goldsmith who's the project scientist for the NASA Herschel project and chief technologist for the Astronomy and Physics directorate at JPL in Pasadena. Thanks both of you.

Dr. GOLDSMITH: Thank you.

Dr. LAWRENCE: You're welcome.

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