A Giant Leap Towards Astronomical Discovery: A Conversation with Professor Wendy Freedman

By Patrick Reilly

February 1st, 2016

On February 1st, Global Voices Interviews Editor Patrick Reilly recently spoke Wendy Freedman, Professor of Astronomy and Astrophysics at the University of Chicago. In her three-decade career as an astronomer, Professor Freedman has been involved in a number of high-profile research projects. From 2003 to 2015, she chaired the board of the Giant Magellan Telescope, a next-generation observatory scheduled for completion in 2021. Professor Freedman came to International House to give her TED Talk about this project.

This event was co-sponsored by the Global Voices Lecture Series and TEDx UChicago. This interview has also been published in The Gate, the partner student publication of the Global Voices Interview Series.

Global Voices: In 2009, you received the Gruber Cosmology Prize for your work on the Hubble Space Telescope Key Project. Can you share your role and experiences with that project?

Professor Wendy Freedman: The Hubble Key Project was designed to measure the rate at which the universe is expanding at the current time. And it was a group of us—about thirty astronomers—an international group that was distributed in Canada and somewhat in Europe. I became a scientific leader of that group. It was about a decade long project, and at the time, the biggest project on the Hubble Space Telescope. It was, in fact, the project that the telescope was built to do, which was to resolve the issue about the size and the age of the universe. When we started, we didn't know whether the universe was ten billion years old or twenty billion years old, and it was a long-term program to resolve that issue.

Global Voices: As part of the National Academy of Sciences 2001 Decadal Survey Committee, you were involved in determining the priorities for U.S. astronomers for the 2000s. How exactly are those decisions made?

Freedman: The astronomy community has been a leader in . . . setting priorities within our own field, and it's made the other sciences now point to astronomy and its success in that area. The general idea has been: a group of people is selected, and they're asked to play a broader role than just representing their own interests. They then get together as a committee to think, "What are the priorities for the field for the next decade? What are the big facilities that we might both build on the ground and also launch into space?” And they prioritize those [facilities]. This way, congressmen don't have to make those decisions — the scientific community is behind it.

And it’s not just the committee. The astronomy community is polled, and people are invited to write in and express their opinions about priorities. So it's a very inclusive process, and it takes about two years. Then there's a report that's written that's refereed by eighteen people in the community, so it's really representative in the end, and it's been very successful for the field.

Global Voices: You mentioned Congress — have funding or other political factors proven challenging at all?

Freedman: It is a difficult era for funding. It's a combination of budgets being tight and the fact that facilities are getting more expensive, because when you build bigger things they just cost more. In the 1980s, it was possible to think about all wavelengths — x-rays, infrared, optical — and building so-called "great observatories”. Now, we can at most do one big space mission or build one big facility on the ground in a decade. So, over time, I think we'll still be able to do many different things, but it's going to take longer.

Global Voices: You’re here tonight to discuss your work on the Giant Magellan Telescope (GMT) in Chile. Early on in that project, a major decision you made was to forge the first mirror* and prove that it was technically feasible, even though you'd only received funding for a small fraction of the telescope's budget. At the time, was that decision a source of concern?

*The GMT will consist of seven 27-foot-wide circular mirrors arranged in a hexagon shape that focus starlight onto a central point. Forging large telescope mirrors such as these is a lengthy, painstaking process.

Freedman: I had been at Carnegie Observatory during the period when the Magellan Telescopes were being built. Those were six-and-a-half meter telescopes at the Las Campanas Observatory, and we used the same technology for the mirrors as we are doing for GMT. With one exception: Those mirrors were simpler. They were six-and-a-half meters wide and they were single mirrors, where you bring the light to focus on the central axis of the mirror. With the GMT, there are six mirrors that are tipped inward and one in the center as the seventh, and all the mirrors are acting as a parabola with a common focus. I knew from the experience with Magellan that the first time you try something different, it takes longer. It has to be tested, and there are things you can't anticipate. And I was very concerned that if we waited to do the first mirror until we had a completed design [for the telescope], it would take decades—literally—to build this telescope. My feeling was that we needed to take a risk and start early, just to show that it could be done.

There weren't a lot of people involved in the decision-making progress early on, because the telescope project didn't yet have a lot of partners. Yes, there was a difference of opinion in how we should proceed, but I did receive seed funding, both from the Carnegie Institution and also from a private donor, and they agreed that we needed to take a risk and move ahead. I think it was the right decision. We cast the first mirror in July 2005, and it wasn't finished in its polishing and testing until the later part of 2012. Had we waited, we wouldn't have been able to cast the first one until this year. So I made absolutely the right decision, and it was very successful, as you know.

Global Voices: Research agencies and universities from several countries are collaborating on the GMT, and among those is Brazil's Sao Paulo Research Foundation. Has Brazil's being a developing country, relatively new to international astronomy, shaped its participation at all?

Freedman: So Brazil has been very involved in other telescopes, such as the Gemini telescope, the SOAR [Southern Astrophysical Research Telescope] telescope, and they've built instrumentation for both of those.* They're very eager to be involved, not just to join and to pay for construction costs, but to get involved with more instrumentation. So I'd say it's been a very positive function for Brazil’s scientists to take to their government, and it also presents the possibility of Brazil’s industry being involved. So they're very active participants. It's been a very good collaboration.

*Note: Neither of these two telescopes is affiliated with the Carnegie Observatory, the GMT's parent organization

Global Voices: International astronomy has, as you know, been around in Chile since the 1960s. From the outset, the Cerro Tololo Inter-American Observatory has given ten percent of observing time to Chilean astronomers. Will the GMT have any kind of a similar relationship with Chile's astronomical community?

Freedman: So you may also be aware that around the same time as Cerro Tololo, the Carnegie Institution began development on the site of Las Campanas, which is where the Magellan Telescopes that I describe are located. And Chile’s agreement with the Carnegie Institution also reserved ten percent of observing time for Chilean scientists. So, when we began the development of the GMT with Carnegie as a partner, we were operating under the assumption that we would agree to those same terms. Then when ultimately we also got the GMT separately incorporated in its own entity down in Chile, that was built in. So yes, ten percent of the time will go to the Chilean community.

Global Voices: As a scientist, what's your biggest expectation for the GMT? What big questions do you hope it will answer?

Freedman: I think there are some really obvious things that the GMT will do well that we can't do with existing telescopes. One of those is the discovery, potentially, of life on other planets, if it's out there and close enough where we have enough sensitivity to detect it. I think that will be game-changing. It will be one of those discoveries that's not just of interest to astronomers, but to the whole world. We will also, I think, open a whole new window and actually see when the first light, starlight, optical light in the universe happened. We’ll see the moment when stars became dense enough to start nuclear reactions, and then fusion, and then light up the universe. Then, we’ll witness how galaxies actually came to be. Right now we know that they form because we're in one, but we've never witnessed it directly. And for me, I think the most exciting thing would be if we could discover something that we can't even imagine right now—a real discovery that we're not anticipating and that only could happen by building a telescope as technically capable as the one we're building.