Using NASA's Cosmic Background Explorer (COBE) satellite to measure microwaves and infrared light that originated with the formation of the universe, Dr. John C. Mather helped verify the validity of the Big Bang theory. Recently named to head up the Office of the Chief Scientist for the Science Mission Directorate at NASA Headquarters in Washington, DC, Dr. Mather was a co-recipient of the 2006 Nobel Prize in Physics.
NASA Tech Briefs: Why don't you start out by telling us a little bit about your background and what led you to pursue a career at NASA.
Dr. John Mather: Okay. I finished my graduate school at Berkeley measuring the cosmic microwave background radiation from the Big Bang in 1974. That experiment was difficult to do, so I thought I'd try radio astronomy and I got a post-doctoral position at NASA Laboratory, the Goddard Institute for Space Studies in New York City. In that same year, NASA issued an A.O. (Announcement of Opportunity) for satellite proposals and I told my post-doctoral advisor, Patrick Thaddeus, that my thesis project would've been better in space. So he said, "Get together a team and call up these people to write a proposal." That was what turned into the COBE satellite.
NTB: The COBE satellite, which stands for "Cosmic Background Explorer," was designed to study radiation patterns from the first few moments after the universe was formed. Tell us about your involvement with that project.
Dr. Mather: Well, I was the project's initiator, from the conversation I had with my post-doctoral advisor. I was one of the leaders in writing the first proposal. In 1976, I moved to NASA's Goddard Space Flight Center in Greenbelt, MD, to, I hoped, become the Study Scientist for the project, which I did. I was also chosen by Headquarters to be the principal investigator for one of the three instruments, which is the one basically that's the follow-on to my thesis project.
NTB: One of the things you learned from that project is that all of the universe's radiant energy was released within the first year after the Big Bang occurred, correct? Why is that significant?
Dr. Mather: Well, it means that the Big Bang theory is an excellent description of the early universe and that it was all pretty simple. We had imagined that maybe it was possible that the fundamental nature of matter is a little bit weird and that, say, elementary particles like protons are unstable and would decay and liberate energy after the Big Bang. That's an example of a wild idea that turned out not to be true. But there were plenty of other wild ideas and bad theories to explain the bad data that had been taken before we flew the COBE satellite.
NTB: One of the phenomena that the COBE satellite uncovered was slight temperature variations in the light detected from the early universe. These variations, it's claimed, indicate density differences that eventually resulted in stars, planets, and the galaxies. Can you explain, in simple terms, how that whole relationship works? How do temperature differences indicate the formation of stars and planets?
Dr. Mather: Yes. In simple terms, the denser regions of the early universe are the ones that are going to grow up to become galaxies because those are the places where the gravity is enough to reverse the expansion. So we'd like to find out where the denser places are.
Now, as it happens, the denser places, we proved, have enough gravity to sort of make the Big Bang radiation lose a little bit of energy coming out of the gravitational field. So what we see is that the dense regions look faint to us, because the photons have lost energy coming out, so that's what we measure, and COBE made a map of that.
NTB: Having established that the Big Bang did occur, do we know what caused it and how long ago, approximately, it occurred?
Dr. Mather: Well, we do know when it happened. It was 13.7 billion years ago, plus or minus a little bit. And no, we don't know what caused it. We have lots of stories about it, but I don't think any of them can be proven.
NTB: Are you continuing to do research in that area?
Dr. Mather: Not me personally. Other people do, of course. One of these days we hope to have a theory of nature that explains the quantum mechanics of gravity. So far, we don't have one. A lot of people have tried, but we don't have one that works, so we don't know. We would need such a thing in order to understand the Big Bang itself, or so we think.
NTB: Your work in this area resulted in you sharing the 2006 Nobel Prize for Physics with your research partner, George Smoot, from the University of California. Can you describe for our readers how it felt winning the most prestigious prize in science?
Dr. Mather: Well sure. It was a tremendous recognition for me personally, for the work that we'd done and, I think, for the whole COBE team, which was a very large team. It was very important to them, too. Somewhere, back then, we knew our work was important, and now the entire world knows that our work was important.
NTB: That's a good way to sum it up. Are you the only NASA scientist ever to win a Nobel prize, or have there been others?
Dr. Mather: Well, I'm the only civil servant. We've had other space scientists win it. Riccardo Giacconi was the father of X-ray astronomy and was also the director of the Space Telescope Science Institute for quite a few years, and he did win the prize (physics – 2002).
NTB: You currently chair the science working group of the James Webb Space Telescope (JWST). Tell us about that project. What will that telescope do that its predecessors couldn't do?
Dr. Mather: Well, the short version [of that answer] is that it's bigger, more powerful, and cold so that it can observe infrared radiation, which comes from two quite different but important places. One is the most distant objects in the universe. We get the infrared radiation from them because of the expansion of the universe; that makes a red shift.
The other major place is things that are a lot colder than stars, like planets and people, emit infrared radiation but not very much visible light. So we can study places where planets are being made, where stars are being made out of the cold material of space. That's the major difference you get with infrared technology.
NTB: When will that telescope be deployed?
Dr. Mather: It will be launched in 2013.
NTB: That seems like a long way off, but it probably isn't in terms of space programs.
Dr. Mather: That's exactly right. There's plenty to do between now and then.
NTB: Last year you were also chosen to head up the office of the Chief Scientist at NASA Headquarters in Washington, DC. What will that job entail?
Dr. Mather: Well, it involves having a view across all of the areas of science at NASA Headquarters and in the Science Mission Directorate, providing some advice about how to make proper balance among programs, and how to take full advantage of the opportunities that exist between different programs.
NTB: Final question. Having helped solve the mystery of how the universe began, what direction do you expect your research to take in the future?
Dr. Mather: I anticipate using the new telescope – the James Webb Space Telescope – and although I haven't written my proposal, I think that I will be working on the first object, how the first stars were made, and possibly also on searches for planets around other stars. I've been giving some thought to both.