NPR Story
12:36 pm
Fri June 8, 2012

Ex-Spy Telescopes May Aid Hunt For Dark Energy

Originally published on Fri June 8, 2012 1:02 pm

Transcript

IRA FLATOW, HOST:

You're listening to SCIENCE FRIDAY. I'm Ira Flatow. Our next story is about one person's garbage being another person's treasure. You know how that works. Well, this one is a very interesting story. Last year, the National Reconnaissance Office, they operate America's spy satellites, well, the National Reconnaissance Office called up NASA with an offer: Would NASA like a couple of old spy telescopes? We don't need them. Could you do anything useful with them? We'll give them to you.

Well, of course NASA accepted the offer, and it's a good move as it turns out because these hand-me-down telescopes are not merely throwaways, they are of higher quality than anything NASA ever built for space. It's not the first time this has happened. Back during the Cold War, NASA got a donation of the Air Force, six lightweight mirrors that were destined for military satellites, which NASA put to use in the multi-mirror telescope out there in Arizona.

Luck strikes again. What about these new telescopes? How soon can they be put to work scanning the skies? What sort of things could we learn with them? Joining me now to talk about it are my guests: Paul Hertz, director of astrophysics at NASA's Headquarters in Washington. Welcome to SCIENCE FRIDAY, Dr. Hertz.

PAUL HERTZ: Thank you very much, Ira.

FLATOW: Sean Carroll is author of the forthcoming book "The Particle at the End of the Universe," about the Higgs Boson and the Large Hadron Collider. Also he's a theoretical physicist at Caltech in Pasadena, and he joins us from there. Welcome back to SCIENCE FRIDAY.

SEAN CARROLL: Hi, Ira.

FLATOW: Paul, tell us about these spy telescopes. They basically just dropped in your lap?

HERTZ: Well yes, that's exactly what happened. They made the offer to us, told us they were available. We actually took about six months and studied the possibility of using them as to whether they could advance the kinds of missions that we were thinking of doing in the next decade or so. And we determined that yes, in fact, they would allow us to do the kinds of science that had been recommended to us by the National Academy of Sciences and other advisory groups.

FLATOW: Give us an idea of how they compare to the Hubble.

HERTZ: Well, the main difference between Hubble is that they're much larger - I'm sorry, that they're the same size as the Hubble, my mistake. The main difference with the Hubble is that they are wide-field. So if you had a camera, back in the old days, when cameras had exchangeable lenses, you might have had a wide-field lens and a telephoto lens.

The Hubble is more like a telephoto lens, it barrels in on a very small piece of the sky, whereas these telescopes are designed to look at a broader piece of the sky, a wide-field view, 100 times as much sky you can see at a time as the Hubble can see.

FLATOW: And why are they so much better quality than what NASA can do?

HERTZ: Well, they're better quality than NASA has ever needed. You know, so that means that the mirrors have been shaped more perfectly than NASA has ever shaped a mirror before, and they also can adjust the mirrors to correct for any slight changes that happen to the telescope when it's launched. It allows you to slightly focus it even sharper after you've put it into space.

And so this would give these telescopes a picture which is as sharp as the Hubble but over 100 times as much of the sky.

FLATOW: Wow, Sean Carroll, does that make it more useful?

HERTZ: Yeah, absolutely. I think that you can do different kinds of science when you have a wide field of view. Instead of picking out an object and studying it as closely s you can, you can pick out thousands or millions of objects and really do statistical surveys to learn what the universe has been doing for the last 13.7 billion years.

FLATOW: What about solving some of the problems of dark energy or dark matter? Would they help?

CARROLL: Yeah, absolutely. I think that - we have dark matter and dark energy, which are two different things. Dark energy is about 73 percent of the total energy in the universe, and it's smoothly spread out, absolutely the same everywhere. Dark matter is about 23 percent. It's a particle, it falls into galaxies. That only leaves four percent for us.

And we have more evidence to say that these things are there, they exist. What we don't know is what exactly they are. We know some of their properties, but we'd love to get these better observations that will help us pinpoint exactly how they evolve and therefore maybe what exactly they are.

FLATOW: Paul Hertz, now that you've got the telescopes there, that's the easy part, isn't it? I mean, you don't have the money, you don't have the - you know, is there any plan to get them actually into space and pay for their operation and use?

HERTZ: Well, we don't have a plan at the moment. What we do have is a plan for making that decision. We've always been - sorry, since the last National Academy Decadal Survey recommended to us that we do a wide-field telescope as our next large mission after the James Webb Space Telescope is launched, we've been studying the possibility of that.

Now we're going to look at whether these telescopes can make that mission better, can make that mission less expensive, or it can make that mission take less time to develop. So we were looking at a mission at the end of the decade, and now we'll be looking at whether these new telescopes can help us in realizing that mission.

FLATOW: But do you need all six of them to do that?

HERTZ: Two.

FLATOW: I'm sorry, both of them to do that?

HERTZ: No, it's - we would only think about using one of them. Using two of them would cost twice as much, and that's probably not the best use of NASA's constrained funding.

FLATOW: And so, give us a timeline that might work out.

HERTZ: If we were to make the decision to use one of these telescopes in a space observatory, we would be making the decision to start sometime around the time James Webb Space Telescope launches, in the 2018 timeframe. And a large telescope mission like this, like the Hubble, would take seven-ish years to build. So you'd be looking at a launch in the middle of the '20s.

FLATOW: Sean Carroll, let's talk about - we were talking about dark energy and dark matter before. There have been studies that suggest that there's not as much dark matter in our solar system, in our galaxy, in the universe as there should be. What do you think about that?

CARROLL: That's right, so the technical term for those studies was a mistake.

(LAUGHTER)

CARROLL: It was found, another paper was written by a couple of astronomers at Princeton and the Institute for Advanced Study, and they showed that, you know, it was - they made an error, which made a huge sigh of relief released from all of the physicists down here on Earth who have built experiments that are trying to detect the dark matter.

So we're still pretty sure the dark matter is there. It doesn't mean it'll be easy to detect, but that's still what we're trying to do.

FLATOW: 1-800-989-8255 is our number. Because some people talked about that they would have to change the laws of gravity or physics to conform if there's not as much dark matter as they thought there should be.

CARROLL: Yeah, absolutely. I mean, dark matter is basically the most boring kind of hypothesis that would fit the data right now. It's still incredibly exciting, but there's even more exciting possibilities, like changing gravity itself. And so we'd love to know which is right and which is wrong.

FLATOW: 1-800-989-8255. Paul Hertz, what's it going to take - you know, you say you're going to come up with a plan to use these telescopes, but what is it going to really take in terms of lobbying to get this going?

HERTZ: Well, I don't think it takes that to get it going, Ira. What it takes is for us to do the studies and come up with a plan and a decision that this would be the next space telescope mission that we want to do and then to work it into our regular budget planning, to use funding which we anticipate being available in our budget at the end of this decade and the beginning of the next decade.

So it just requires us to do the kind of planning for a future mission that we always do and to then, after we've made those plans, to be talking about it with our scientific community and with our stakeholders in our government to make sure that we're all on the same page about this being the right mission to go forward with after JWST.

FLATOW: And what would be the prime science objective of, let's say, your first mission or your first observation?

HERTZ: Well, that would depend on exactly what we picked as the mission for this telescope and what instruments we put on it. Certainly one of the configurations we'll be studying will be to use these telescopes to realize the science of the wide-field infrared survey telescope, which was the number one priority of the National Academy's Decadal Survey, and that telescope's prime science is to study dark energy, as Sean Carroll was just talking about, but also to detect planets around other stars and to do a wide-field survey of the science that can be realized by looking at the structure of our own Milky Way Galaxy.

I don't know what would be the first science that would come about when we put together an observing plan for an observatory like that. I do know that the first image we take would be breathtakingly beautiful, and we'll be excited to share it with the American people.

FLATOW: Are you a bit jealous of the sort of technology they get to use at the Department of Defense? I mean, these telescopes are the hand-me-downs. Imagine what they have, what they're using.

HERTZ: Well, jealous is probably not the right word. I feel very fortunate to be an inheritor of all the money and technology development they've invested in it. You know, this is not a unique occurrence in astronomy. You already mentioned the mirrors that were used on the multiple-mirror telescope.

But all of the CCD cameras that we use both on ground-based telescopes and one space-based telescopes have heritage to detectors that were developed by the military for military purposes. And then once they're declassified, they become of use to astronomy. Also, the active-adaptive optics that are used in ground-based telescopes to correct for atmospheric blurring is a technology which we adapted from military uses.

FLATOW: Let's go to Chris in Twin Falls, Idaho. Hi, Chris.

CHRIS: Hello.

FLATOW: Hi there.

CHRIS: I'm a former employee of the space telescope project. And I'm curious that even though these military satellites might have greater optical capability, I'm really wondering how they're going to manage to do the sort of accurate pointing like Hubble, because of course Hubble uses guide stars. And presumably if you're looking down at the Earth, guide star locking capability is not something that they're probably using. I'm just wondering how they would maintain the sort of accurate pointing that Hubble does. And I'll take the answer off air.

FLATOW: Thanks.

HERTZ: Well, Ira, I have no clue how - why satellites work.

(LAUGHTER)

FLATOW: Sean, you can't help us out on that one either.

CARROLL: Well, the good news is with a wide-field telescope you don't need to be as accurate in your pointing.

FLATOW: Give us an idea. When you say wide field - if I were looking up at the sky, what - and I put my hand out - how much of the sky would that lens, telescope take in?

CARROLL: That's probably one for Paul. It's not that much. I mean, you know, you get half a degree on the sky, the size of the moon, that's huge for astronomical purposes. It's probably much less than that. But it's - you know, we shouldn't forget that astronomy is in the middle of a sort of a gradual revolution.

When I was a grad student 20 years ago, we looked at galaxies one galaxy at a time. And when I say we, I don't mean me. I mean the people who look at galaxies. But since then, the data deluge that we've been blessed enough to be part of has absolutely changed how we do astronomy.

The discovery of dark energy in 1998, the acceleration of the universe, was completely made possible by new technology that let us scan large parts of the sky over and over again, and this is just another step in that direction.

FLATOW: Mm-hmm.

HERTZ: And, Ira, I want to - I'm going to disappoint Sean by saying that, in fact, the field of view of these telescopes is something like one and a half degrees or larger.

CARROLL: Wow.

HERTZ: So it's three full moons across.

CARROLL: That does not disappoint me.

(LAUGHTER)

FLATOW: Sean, do you wish you had control of these telescopes?

CARROLL: No. Nobody wishes that I had control of these telescopes...

(LAUGHTER)

CARROLL: ...but I'm happy to propose ideas they can shoot down and occasionally interpret the new discoveries they're going to bring to me.

FLATOW: Yeah. Who would - and, Paul, who would be controlling them once they got up there?

HERTZ: Well, that would be part of the plan for how we would develop and then operate telescopes like this. Right now, for the various space telescopes we have working, what we do is we set up science centers who are responsible for picking amongst the various good ideas that astronomers propose for using those telescopes, and then constructing an observing plan and then uploading that plan to the telescope so it can be used.

We have a Space Telescope Science Institute in Baltimore, which is in charge of the Hubble Space Telescope. We have the Chandra X-ray Center in Cambridge, Massachusetts, which is in charge of the Chandra X-ray Observatory. And we have the Spitzer Science Center out in Pasadena, California, which is in charge of the Spitzer Space Telescope.

FLATOW: This is SCIENCE FRIDAY from NPR. I'm Ira Flatow, talking with Sean Carroll and Paul Hertz.

Why not - you know, if the future of NASA is sort of jobbing out some of its work, why not just call up Elon Musk and say, hey, you know, build me a rocket to take this thing up there into outer space or into circular orbit and we'll work together in private industry on it?

HERTZ: Wow, that was a surprising question.

(LAUGHTER)

HERTZ: So, in fact, you know, when NASA builds space telescopes and missions, in fact, most all of the work is done by our partners out in industry.

FLATOW: Right.

HERTZ: The Hubble Space Telescope was built by TRW. It's operated by the Associated University for Research in Astronomy. The instruments were built by different university groups. So it's common for us - after we have come up with a plan for what our space telescope is going to be - to request proposals from people who can do a great job of the various pieces and put together the best performing team that we can.

FLATOW: Good answer.

(LAUGHTER)

FLATOW: But, you know, maybe he can do it cheaper then, or any private person might be able to do it more cheaply and quicker.

HERTZ: Our calls for proposals are open to all proposers.

FLATOW: Sean, what do you...

HERTZ: Anybody who has a good idea, NASA is listening.

FLATOW: Sean, what do you - what would you do for finding dark matter with this? Give me a little more specifics of how you would use it as a survey.

CARROLL: Well, the thing that you can do when you have a survey is sort of average over things that are going on. The wonderful thing about galaxies, for astronomers, is that they all have their individual little personalities. For physicists who want to know, you know, what is the basic composition of the universe, those wonderful idiosyncrasies get in the way.

And what a survey lets you do is say, what were galaxies like 10 billion years ago versus five billion years ago, versus one billion years ago, and so forth? And then by looking at that evolution over time, you can say, well, what has the dark matter been doing? What has the dark energy been doing? And that's just the way astronomy is headed these days.

FLATOW: Mm-hmm. And do we have a good survey, a good number that we think that - for dark matter, a confident number?

CARROLL: We have a confident number in how much of it there is. It's about five times as much dark matter as there is ordinary matter. And by ordinary matter we mean every particle ever discovered in the history of physics. So it has to be something new.

And we have this wonderful multi-pronged program for finding it. We have astronomy, like we've been talking about. We have direct detection underground, where we have big labs that are looking for dark matter particles bumping into them. And then we have the Large Hadron Collider that's trying to make the dark matter by smashing protons together and seeing what comes out.

FLATOW: It's possible to actually make it in the Hadron Collider?

CARROLL: Yeah, absolutely. In fact, one of the reasons why the Higgs boson in particular is an exciting thing to study is because the Higgs might be the single particle that connects ordinary matter to dark matter. It talks to both the electrons and the quarks that we know and love and do whatever the dark matter is.

FLATOW: So a Higgs boson might decay into dark matter?

CARROLL: That's right. And so you - it presents a challenge for the particle physicist because the dark matter is dark. It doesn't show up. It doesn't leave a trail in your particle detector. But they're sophisticated enough to know that there can be missing energy, that you've created a particle and you know you didn't see it. So you can talk about what its properties were, how it was created if it is occurring in a decay of a Higgs boson in the right way; there would be a really good reason to think, a-ha, we're on the trail of the dark matter.

FLATOW: Wow, that's exciting to think about. Thank you, Sean. Sean Carroll is author of the forthcoming book, "The Particle At the End of the Universe," about the Higgs boson and the Large Hadron Collider. He's a theoretical physicist at Caltech in Pasadena. Paul Hertz is director of astrophysics at NASA headquarters in Washington. We'll be watching for that plan and get those space telescopes into orbit. Thank you, gentlemen, for joining us this hour.

HERTZ: Thank you.

CARROLL: Thank you, Ira.

FLATOW: We're going to take a break. When we come back, the SpaceX Dragon flew safely to the Space Station and back, carrying a load of cargo. How soon are astronauts going to get on there? We'll have a chat to discuss that. Would you like to go? Stay with us, we'll be right back after this break. Transcript provided by NPR, Copyright National Public Radio.

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