Researchers Map Dark Matter to Account for the Unseen When astrophysicists try to account for all the matter in the universe, things just don't add up. What we can see accounts for only about 4 percent of everything. The rest, they reason, is dark matter and dark energy. This week researchers unveiled a new map of the dark matter.
NPR logo

Researchers Map Dark Matter to Account for the Unseen

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript
Researchers Map Dark Matter to Account for the Unseen


This is TALK OF THE NATION Science Friday. I'm Ira Flatow. First up this hour, our continuing look at the new Congress and its impact on science. The new Democratic Congress is promising swift and radical changes to Republican programs, but scientists are watching closely to see if lawmakers will pick up on some unfinished business.

The outgoing Congress, for example, failed to pass spending bills for the current fiscal year, leaving many agencies with budgets capped at 2006 levels. Physical science programs, in particular, are being hit. The flat funding threatens to cancel basic research in physics and even close some facilities.

So what can Congress do to get science back on track? If you'd like to join our discussion, give us a call. Our number here is 1-800-989-8255, 1-800-989-TALK. And as always, you can surf over to our Web site at

Bill Broad is a senior writer at the New York Times here in New York. He's written about this in the times, and he joins us today by phone from his office there. Welcome back to the program, Bill.

BILL BROAD: Hi, Ira. Thanks for having me.

FLATOW: You're welcome. Michael Lubell is chair and professor in the department of physics at City College of the City University of New York, and director of public affairs at the American Physical Society in Washington, where he joins us by phone. Welcome to the program, Dr. Lubell.

MICHAEL LUBELL: Thank you very much, a pleasure to be with you.

FLATOW: You're welcome. Bill, we should emphasize that it's not the case that science budgets have been cut, right? Because the last Congress failed to pass these new budgets, funding is stalled at last-year's levels, right?

BROAD: Yeah, that's right, but the bad news is that it turns into a cut because of that old demon, inflation. If they're held at '06 levels, that means that because it's getting a little more expensive to do science, they're having a little less money to do it with. So that's anywhere from three to four percent, or even five percent less in some areas.

For instance, I was talking to some people at Woods Hole Oceanographic Institute on Cape Cod. Their fuel costs have gone through the roof, you know, in the last two years. Oil for - and gas for their ships, and they're running at about five percent inflation. So keep freezing the budget means a serious drop for them.

FLATOW: Speaking of Woods Hole and other places, I've heard from places like those that they're also losing their public information people, because those are the first people to go in a budget cut.

BROAD: Sure, right. I mean, you know, you try to plow on with the research, but talking about the research gets the axe. You're absolutely right. So we learn less about what is really kind of a quiet crisis.

FLATOW: Michael Lubell, do you agree?

LUBELL: I completely agree with Bill. And I say, in fact, for one of the largest funders of research in the physical sciences - the Department of Energy's Office of Science - is caught in an even worse bind. Because in the previous year, the office sustained about a four percent cut, and it was largely the result, in the last analysis, of Katrina.

And in power, or I should say level, of effort, they lost between seven and eight percent, and then you tag on another three percent this year, and you're 10 percent behind where you were two years ago. And this comes on the heels of several decades of reductions in real level of effort, amounting to about 20 percent. And it comes at a time when the United States is facing increased competition from abroad.

FLATOW: What kinds of competition are you talking about?

LUBELL: Well, a number of years ago, the United States was the number one destination for students from all over the world. That is no longer the case. Asian students today, mostly stay at home to carry out their doctoral work or advanced education. And the investments are being made throughout the world in large facilities, universities, and in small facilities - mostly because there's a recognition that it is intellectual capital and scientific discovery that drives technology.

And the time to market from discovery today is no more than a year, and if you're not located in the place where the discovery is taking place, you're at a sever disadvantage. And we see the increase in the number of patent applications from the rest of the world - U.S. patent applications - gaining on American companies.

In the next few years, we will be completely outpaced. We've also seen our advanced technology trade drop into severe deficit conditions since the year 2000. So it's a real competitive race, and as things go along this way, we're not going to win it.

FLATOW: Given the scenario of the budget being flat and actually suffering now because of inflation - as Bill mentioned - Mike, can you now drill down and let's talk about some specific research projects that might be in danger of being cancelled at these lower funding levels?

LUBELL: Oh, sure. There's - what I'll do is to talk about the national facilities that the Department of Energy operates. These laboratories are open to researchers from around the world, from around the United States, and people who are in various government agencies - they carry out research in materials; they carry out research in biomedicine; it's right across the board. And there's an awful lot of basic science that is done, which doesn't have, necessarily, any immediate payoff.

Last year, for example, the relativistic heavy ion collider - a big, big machine, a ring that is located at Brookhaven National Laboratory - was going to have to be mothballed at just the time that it was beginning to produce very, very dramatic scientific results, because they didn't have the money to operate it.

A philanthropist stepped in and saved them last year, but if this current budget continues with a continue resolution, that machine will be turned off.

Another large machine at Fermi National Laboratory - the Tevatron, which is exploring very basic physics - would also be turned off, at least for part of the year.

Another facility that is just about to come on - which is in Tennessee, called the Spallation Neutron Source, in which we've just finished investing $1.4 billion, incidentally, a machine that was completed on time and on budget, just ready to go - and it would not be able to start. That would reduce its capacity and essentially extend the - we make a down payment on the construction of it, and then we can't use it. It's a foolish expenditure of money in that respect.

FLATOW: That's at Oak Ridge?

LUBELL: That's at Oak Ridge National Laboratory in Tennessee. Another example, we have a commitment to the International Thermonuclear Experimental Reactor - it's an international project - we would not be able to participate in this thing to the full extent that we said we would.

This is a fusion energy machine. And I could go on and on with major cuts in X- ray light sources, which industry and pharmaceutical companies rely very heavily on. These would all suffer major reductions. In the last analysis, the estimates are that several thousand scientists would lose their jobs.

FLATOW: Bill, many of these projects are funded by scientific agencies in the government, like the National Science Foundation. Does that mean that their budgets are being cut also?

BROAD: They are losing - they are, you know, because of inflation, they're experiencing these cuts. But in the case of NSF, they were slated for a $400 million increase in this current fiscal year. That's not going to materialize. And so, across the nation, all these universities, you know, excellent schools that were planning and bending over backwards to prepare themselves for these new NSF programs. For instance, a super-duper super computer program that was going to help link universities, you know, at the cutting edge of computing science for basic science and engineering research. Gone. You know, they just can't do it now. All of that work that they did in anticipation, you know, of this new program is just, you know, over. They don't - they're not getting the money. And, you know, as Mike was saying, it's a different playing field now. Globalization has destroyed our monopoly on the best and the brightest. Now people have lots of options.

And you go to these places - like I visited Brookhaven a couple of years ago and looked at this particle accelerator, and it's a little case study in internationalism. There are people from all over the planet working there, and they're very bright and it's a very mobile workforce. And if those machines turn down - well thank you very much, they've got lots of alternatives. Including, you know, going to work for, you know, financial giants that would just die to have their mathematical skills for working advanced algorithms in finance. So...

FLATOW: Yeah, going to Wall Street like many of them have.

BROAD: Why not?

FLATOW: Isn't the new Congress or the Democrats in power, are they not more sympathetic to this? For example, Rush Holt, who's a physicist himself from Princeton who now is as part of the majority instead of the minority.

BROAD: Right. They are but their line is - and I think it's sincere - is that they inherited a nightmare - this budget. The last - the Republican- controlled Congress didn't do due diligence on this budget and they can't patch it together. They're so overwhelmed with the current business, with the any day now - a new budget that the president will present for '08 - and they say we don't have the manpower and the time to handle two budgets at once. We're going to have to hocus focus on the - all the hearing work and the serious preparation that this to be done for the '08 budget, which is about to land.

LUBELL: Ira. Ira, I would add one more thing to what Bill has said. And that is that it's been a bipartisan commitment to address research issue. The Democratic House members a little over a year ago issued their innovation agenda, which called for doubling spending - actually investment in basic research in the physical sciences across all agencies. And the White House, in the competitiveness initiative announced a year ago, made a similar commitment. This is not a partisan issue at all.

BROAD: Absolutely. That was one of the - I mean people - you know, scientists can cry wolf like anybody else, right? But what's unusual about this period right now is that there was a huge consensus, especially for the physical sciences, that things were out of whack and we needed to do some serious rebalancing. Everybody was on board and then nothing happened. And you talked to guys like the - the head of Brookhaven or the head of Fermilab in Illinois - and they're just shaking their heads. They just - they can't believe it.

FLATOW: All right. We're going to take a short break, stop shaking our heads, come back, talk more with Bill Broad and Michael Lubell, take your questions. Talking about science budget cuts in this fiscal 2007 budget, which started last October in case you can't keep track of budgets and how they happen. So stay with us. We'll be right back after this short break.




FLATOW: You're listening to TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow. We're talking about funding in science - the shortfalls in funding in science, especially in the physical sciences: physics, chemistry, things like that. This hour on TALK OF THE NATION: SCIENCE FRIDAY with Bill Broad, a senior writer at the New York Times, and Michael Lubell, professor in the department of physics at City College. Our number: 1-800-989-8255. So Michael, are we just left with this to wait it out? I mean, do people hope next year's a appropriations will come from behind and make up?

LUBELL: Ira, I don't think we can afford not to wait a year. We certainly can't and the rest of the world is not going to wait for us to decide how we're going to do our political business. The situation in high technology is, once you start to lose you're going to fall further and further behind and it becomes much more difficult to catch up. Congress does have an opportunity in writing a continued resolution to make adjustments. And since there has been bipartisan support for science, basic science and they physical sciences in particularly, they still have the opportunity to act on it.

This is not a - the door has not been shut. It's still open a crack. And of course we were hoping that sane people will make sane decisions. Sometimes that's not how politics works, and we're still hoping to see that.

FLATOW: 1-800-898-8255. A couple of phone calls. Elliot in Washington. Hi Elliot.

ELLIOT: Yes good afternoon. Enjoying your show very much.

FLATOW: Thank you.

ELLIOT: Wanted to make a couple of points here. When Mr. Broad was speaking about the inflation whammy that science takes and federal agencies take, on top of that you have to factor in the fact that government agencies often have to absorb the cost of pay raises for their employees. So that adds another two, two-and-a-half, three percent to the loss. And I agree with the point that any delay just pushes being able to catch up far, far down the road. Can't have, under a continuing resolution, new starts that you had planned in fiscal '07 because you're working under fiscal '06 money. So that research and work gets pushed down the road. We're seeing at our agency now.

FLATOW: What agency is that? Elliot?

ELLIOT: Yes I'm sorry, I didn't get that part.

FLATOW: You didn't tell us what agency you were working with.

ELLIOT: My apologies. I'm the public affairs director for the Nuclear Regulatory Commission in Rockville, Maryland.

FLATOW: Ah. You're agency, too, is getting hit?

ELLIOT: Very much so. We - we're a small agency. We are working with $95 million, or 12 percent less than we had anticipated working with this year. We do a lot of licensing activities for nuclear facilities. We're having - we're seeing some impacts of delaying that work. I can't speak specifically to research, but when you're stuck with last year's budget and you can't start new projects and your focus is safety, it has an impact.

FLATOW: Mm hmm. Bill, this is what we were talking about, these people flying under the radar screen.

BROAD: Yeah and here - it's not all, sort of, airy-fairy(ph), you know, theoretical physics and that stuff. Listen to this list from NSF. Here's some of the things that are up in the air right now taking hits. A big ship to explore the arctic - you know, looking, doing evaluations of thinning polar ice, i.e., there's a global climate change and what's really going down. A $310 million observatory that is supposed to wire the oceans, you know, from the seabed to the surface to help answer basic fundamental research enigmas. People don't realize that the ocean is one of the outstanding issues in the global climate change studies and enigmas. I mean, we don't understand it that well and yet we know it plays a huge roll in moderating the planet's overall climate. So you've got to nail that variable better.

Another one is this NSF program for - to an international - for the U.S. contribution to this international polar year, which is just happening. It's about 12 countries. They're all pooling their money and it's hundreds of scientists. They're all getting ready to really go to work on the poles and do a very detailed baseline study - which will also be important for climate change. Well, our contribution is up in the air now, and those little things hurt.

FLATOW: Ann(ph) in Marysville, California. Hi Ann.

ANN: Hi, I was wondering whether if the budget that focuses so much on the war in Iraq, does that affect the funding at all for science and research and all that?

FLATOW: Mike, what do you think?

LUBELL: Well I would say that the war in Iraq affects everything, and science it not singled out. When you're paying $2 billion a week for a war effort, other things in the budget do suffer. Science just happens to be one of the many, many things in the discretionary - what we call the discretionary civilian budget. So obviously, as everything is hit, science is hit as well.

FLATOW: That's the cost of a whole project - one week there.

LUBELL: Yes that's exactly right.

FLATOW: Many projects together.

LUBELL: Yeah, if you look at it as, I said, this Spallation Neutron Source - this big machine in Tennessee - cost $1.4 billion, and we go through that in ten days in Iraq spending. It's quite amazing. I guess what I would also add is that science is not a spending program. It's a real investment. The returns are very substantial. Economists estimate that for every dollar that's spent we reap economically a benefit of at least $1.50 and maybe even higher. We oftentimes don't realize what we get, and I'll just give one very simple example, and it's the iPod. Apple just announced a new one.

But if you take a look at the iPod - the hard drive in it - that began with funding from the Department of Energy, Office of Science back in 1988. The lithium ion battery which powers it also came from DOE's investments in electric chemistry. And the liquid crystal display and now the new color one, of course, that came from the National Science Foundation, NIH, and the Department of Defense. These are federal investments and they've made their way into the commercial economy. Most people don't realize where it all started.

BROAD: If I can raise a point, I think in addition to the war, people who don't follow this closely are sort of - can't believe it, in a way, because we're so dazzled by the biomedical progress that we make as a nation. And the fact that there's this unending, you know, display of, you know, creativity and innovation all around us that saves lives and does wonders all the time. I don't think people realize that or the biomedical part of the federal budget is five times larger than the physical sciences part. You know, the physical sciences - all this stuff that we're addressing - is a tiny, you know, fraction of the overall federal budget. And it's been, you know, dropping, you know, relative to the other stuff.

So it's kind of getting lost down, as you said Ira, under the radar. And it, you know - it's not a good thing.

FLATOW: You would think that with Hurricane Katrina and the other hurricanes, and we didn't have a big hurricane season this year - but considering we know it's going to happen real soon now, again, that research for the oceans - you're talking about the censors on the seafloor, things like that, would be a higher priority.

BROAD: Right.

FLATOW: It just doesn't - you know, I've always said that if Washington were located on the San Andreas Fault line or in New Orleans, we'd all be getting funding for these types of projects, but it's not.

BROAD: Right.

FLATOW: It's sort of out of sight and out of mind there.

LUBELL: Yea Ira, what I would add to that is it has to do with people's time horizons. The time horizon for members of Congress is two years. The time horizon for CEO is about 90 days. Time horizon for consumers, probably tomorrow - one day. And the time horizon for science is five to ten years. That's one of the problems we face.

FLATOW: Mm hmm. So it doesn't look like we're going to get a continuing resolution or some sort of increase on this unless we shout loud enough about it.

LUBELL: Exactly.

FLATOW: In the science community.

LUBELL: I think the public ought to be screaming, because ultimately it's the public that is the beneficiary in this. It's not the scientists. The scientists do this thing - do their work because they're excited about it, but they also believe they're making major contributions to society as a whole. And it's the public that ought to be outraged about what's happening.

FLATOW: All right. I don't think we have a better place to sum up and to thank you gentlemen for taking time to be with us. Michael Lubell, Chair Professor in the Department of Physics at City College in New York and Director of Public Affairs at the American Physical Society in Washington. Bill Broad, senior writer at the New York Times. Thank you gentlemen for taking time to be with us.

LUBELL: It's been my pleasure.

BROAD: Thank you.

FLATOW: You're welcome. Have a good weekend.


FLATOW: When astrophysicists try to account for all the matter in the universe, kind of a cosmic audit, things, they just don't add up. The ordinary matter, the stuff that makes up the stars and the planets, the mountains, the trees, you and me, is only - by their estimates - a small chunk of all the matter out there. About four percent - four percent of everything. The rest, they reason, is unseen stuff: dark matter, dark energy. The astrophysicists know if - they know - they know it's there, or else the books wouldn't balance. But they don't know really what it's made of, or exactly what it does. Last year, from observations of the bullet cluster of galaxies came the best proof to date that dark matter exists.

And this week, researchers unveiled a new map of the dark matter, at the meeting of the American Astronomical Society. It's also been published online in the journal "Nature."

And joining us now to talk about the map, which you can see on our Web site at, is Richard Massey. He's a post-doctoral researcher in astronomy at Caltech in Pasadena. And he joins us from KPCC in Pasadena. Welcome to Science Friday.

RICHARD MASSEY: Hello there. Thank you very much.

FLATOW: How are you? There's a beautiful map. It's not with the real colors of what's going out there.

MASSEY: Well, that's actually the crux of the problem that dark matter is invisible, so we can't see it and we really can make a map using the real colors because there aren't any. So we'd have to make this false color map. Yeah. Sure.

FLATOW: Now, how do you - how did you know? How did you get it to show up if it's dark?

MASSEY: Right. And that's the - yeah, that's the crux of the issue that we can't see it directly so we have to find some ways of sort of proving its indirect effects on other things that we can't see. Now, there have been a few ideas about how to do this. The best way to visualize, sort of, the large scale structure of the dark matter - see how it affects the universe as a whole - is by a technique called gravitational lensing.

So the idea is we can't see the dark matter itself, but we can see galaxies, which are behind it. Just ordinary, very noble galaxies. Now the light from those galaxies has to pass through the dark matter on its way to us. And during that journey, it's affected by the dark matter. It's almost as if we see the dark matter in silhouette against these distant galaxies. There's not really silhouette. It's not that the galaxies appear faint, it's just that they actually appear distorted, because the dark matter acts like a lens and alters the path and the shape of the light coming from the galaxies.

FLATOW: So it interacts with the gravity?

MASSEY: Yeah. So that's the thing about the dark matter is that it doesn't interact in any other way. That's why it doesn't shine. It didn't even reflect light. But it does interact through its - through gravity. And so, all the ways of seeing or inferring that there must be some dark matter, adding at the books, is from its gravitational effects on other things.

FLATOW: Now, if it doesn't interact with the particles that we normally have around us, but it does interact with gravity. I had this thought - maybe, I'm totally off about it - could it be that the particles that carry gravity be in the dark matter realm - which we don't know what that stuff is yet, right, - instead of the normal matter realm. And perhaps, that's why we're finding it so hard to find particles that carry gravity?

MASSEY: The two questions are sort of inextricably linked, in that dark matter was first postulated in say - in the 1933 by Fritz Zwicky. And he was doing his, adding up his books on these spiral galaxies, which were - which are spinning way too fast to be held together by the gravity of just the stars that they contained. He totaled the amount of mass in the stars - found these galaxies would fly apart if it weren't for the dark for - some additional dark matter.

And so he postulated the idea that, well, yeah, okay. There must be some dark matter there that we can't see, but is sort of acting as a gravitational glue to hold these galaxies together. But equally, people have suggested that it's not the amount of matter or the amount of mass that's wrong in these galaxies. That's sure the laws of gravity that we've got wrong. And people have suggested various, different, alternative theories to Einstein's general relativity, which is the best theory of gravity that we have at the moment.

Now, there'll be a lot of works too, because, I mean, Einstein was a very clever guy, and we got to make a lot of things match with these new predictions of what the gravity might be. And they're having a lot of difficulty with these latest results, particularly from the bullet cluster that it seems even when if gravity is wrong, then there is some - then, they need some dark matter there as well.

FLATOW: Mm-hmm. Described what we'll see when we'll look at the map that you've created. It's very interesting map.

MASSEY: So yeah. The first thing that strikes me about looking at this map is actually that there are enormous voids. There are these vast regions of space in which there's absolutely nothing at all. But then, sort of, around these voids is a crisscrossing network of strings of dark matter, very long and relatively thin strings of this mysterious dark substance. And that forms a scaffolding, crucially, in which the ordinary that everything that we know and can touch and feel, in fact, everything that science sort of knows about basically.

All these ordinary matter that falls into the dark matter scaffolding is later construct and built up into their, into galaxies and stars and planets that we find ourselves in today.

FLATOW: Is it trapped by those strings?

MASSEY: It's - well, yeah. And in fact, it's - they're both gravitationally attracted to each other, so over time, they just - and it fall together. And importantly, the dark matter has this sort of initial lead-time over the ordinary matter. It starts collapsing into these structures very early on in the universe, when everything else was just a fairly smooth soup. So the dark matter collapsed first, and then, sort of, by its own gravity, pulled in the ordinary matter, and helped concentrate into the kind of densities where begin to form stars.

FLATOW: So you can see clumps of dark matter wherever there are clumps of galaxies, for example?

MASSEY: That was - that is exactly why the two are really closely linked. And we wouldn't have the kind of universe that we find ourselves in today without the dark matter, both for its scaffolding thing, and also in an exact analogy actually to the dark matter holding, spinning galaxies together. The universe expanded away from the big bang and a lot of explosion. And without the dark matter, it would've just gone, you know, enormous. Got - would've exploded.

Everything would've deleted and we wouldn't - can't have life. The dark matter, exactly the same way that help spinning galaxies together. It's held the whole universe together. And it's been an strict and it had been, you know, a vital element in the role - in its role of shepherding the galaxies and forming habitable universe today.

FLATOW: But having the map doesn't answer the question about what the dark matter is.

MASSEY: Yes. So we certainly answered the first question about where it is. And the question of what it is, is going to involve, you know, lots of research for, you know, which we hopefully will get lots of scientific funding for over next years. It does give us a few, sort of, tantalizing hints about what it might be and what some of the properties are. I mean, for example, one of the questions about this dark matter is - let me just emphasize, we're really starting at the very beginning. We have a very little idea what this substance is, even though it completely dominates the massive, or the budget of matter, in the universe.

So one of the tantalizing hints that it give us is to do with the dynamical temperature of the dark matter. In other words, how, sort of, warm or cold it is. If it's so warm - is these lightweight particles, which whiz around the universe and end up just moving really fastly, or fast, or hustle and bustle. If it's cold, it's sort of sits more sedately where it's put and just stays there.

FLATOW: Dr. Massey, you have to - well, you have to hold that thought.


FLATOW: Because we have to break away. So stay with us. You've joined the crowd of people I've rudely interrupted. So stay with us. We'll be right back to more with Richard Massey, about dark matter on TALK OF THE NATION: SCIENCE FRIDAY. So don't go away, we'll be right back.

I'm Ira Flatow, and this is TALK OF THE NATION Science Friday from NPR News.


TALK OF THE NATION: Science Friday. I'm Ira Flatow. We're talking this hour with Richard Massey, you know, talking about dark matter. But first, a program note. Coming up on Monday, Neal Conan talks with Iraq's acting ambassador to the United Nations about President Bush's new strategy for that country. And Faisal Istrabadi gives his response to the challenges now facing Iraq, and takes your questions. Here's your chance to question an Iraqi official. That's Monday, on TALK OF THE NATION from NPR News.

All right. I say we're talking this hour about dark matter. When I rudely interrupted Richard Massey, you were talking about - tell us what you are talking about. I don't want to rudely interrupt you again.

MASSEY: Oh, well, I was just saying that, yeah, I mean, the holy grail really in this field is going to be to try and figure out what this dark matter is. And, you know. And, you know, we've made our first steps along these lines. We know it's some sort of cold, dark matter. And we know it's there, but we still need to figure out what on Earth it is.

FLATOW: Hmm. 1-800-989-8255 is our number. We will - I'm sure there's a - lots of interest in this. Let's go to the telephone. Let's go to Lewis(ph) in Newport, New Hampshire. Hi, Lewis.

LEWIS: Hi. How are you doing?

FLATOW: Hi. How are you?

LEWIS: I'm doing all right. I was wondering whether dark matter is something that's entirely out there or whether we're speculating that there maybe dark matter locally. And if we're talking locally, whether we're talking about floating around within our galaxy or whether we may actually be surrounded by dark matter at every moment. We did now know it because we can recognize it.

MASSEY: Not yet. You're quite right. No need to be worried. This stuff doesn't do anything to us. That's the kind of point in the problem that we've had in finding it. But, sure, it's everywhere. It's all around us. It passes with us, through us all the time and we don't notice it. We don't - just don't notice it.

FLATOW: Well why, if we're just four percent - I mean, the light of the matter that we take for granted everyday is just four percent, and dark matter is, you know, 25 percent, and dark energy is 75 percent, 70 percent - something like that. Why don't we exist at all? I mean, why do we have four percent of us when all the other stuff is dark.

MASSEY: And that's a very deep, philosophical question. I mean, some people would state, we're here and were the sort of end result of the universe. We're the ones who observed it. But it's - lucky for us that we do exist though.

FLATOW: What other kinds of experiments can you perform to see? Is this the way now that scientists will be looking to see dark matter, through this lensing effect? Is this the standard operating procedure now?

MASSEY: It's now about the most exciting way of seeing it under - on very large scales, of tracing out this sort of filamentary distribution of matter on the very largest scales in the universe, that really given its overall evolution. It's not as useful as finding it nearest. And you know, there are other astronomical techniques for finding it nearest. For example, there's micro lensing in our own galaxy, and they can also look at the way that the stars are rotating very quickly around the black hole at the center of that galaxy.

But there are ways to see things that are invisible, nearer to us. But then, of course, particle physics and particle accelerators have a very important role to play in actually getting, sort of, you know, some physical stuff in a laboratory.

FLATOW: Does the dark matter tend to counteract the dark energy, the repulsive force?


FLATOW: Slowing down the expansion, perhaps?

MASSEY: Right. That's - yeah. That's exactly right. There's a giant, cosmic tug-of-war going on. The universe, you know, expanded from it from a big bang initially. And the mass of the dark matter is trying to put it all back together, just like the mass of the Earth pulls an apple back down to the Earth. The dark energy is an even more mysterious and, you know, another step on from that that. It acts as sort of some strange, anti-gravity (unintelligible), which is actually accelerating the expansion of the universe and making the whole thing happen faster. It's a giant, you know, tug-of-war.

FLATOW: Earlier this hour, we were talking about science funding, and I think we should point out that your data for this map comes from the Hubble space telescope. And right now, looks like the latest news this week is that the Hubble is saved.

MASSEY: Yeah. That's great.

FLATOW: That's a NASA service mission.

MASSEY: Yup. And I say, it's lovely. It's wonderful. I can't emphasize in at how amazing the Hubble has been in terms of its astronomical research output for, what, for researchers. And, you know, it's had a huge impact in terms of visibility and, you know, popular, you know, outreach. It's one of the, you know, NASA's greatest achievements in terms of public interest per dollar spent. It's an astonishing gem of an instrument.

FLATOW: Yeah. I couldn't have said it better. Thank you for taking time to join us. And good luck to you on your imaging.

MASSEY: Thank you very much.

FLATOW: Happy hunting.


FLATOW: Richard Massey is a post-doctoral research astronomer at the Caltech in Pasadena.

Copyright © 2007 NPR. All rights reserved. Visit our website terms of use and permissions pages at for further information.

NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.