Alycia Weinberger’s research includes studies of space dust to better understand how this dust becomes part of planets and what those planets’ compositions might be. She uses ground and space telescopes to study disks around young stars and search for such components as water ice and organic molecules. Weinberger also looks for young planets and studies low-mass stars to better understand the evolution of planetary systems. Credit: Roberto Molar Candanosa, Carnegie DTM.
In 1998, Alycia Weinberger joined a team of scientists at UCLA working with the Near Infrared Camera and Multi-Object Spectrometer (NICMOS), just installed on the Hubble Space Telescope. The NICMOS team had data on galaxies, brown dwarfs, and other kinds of exciting science. As a doctoral student at Caltech, Weinberger had been studying active galaxies, which have massive, accreting black holes at their cores. But as a NICMOS postdoctoral researcher, she found that the instrument also was taking data on circumstellar disks—and that not many people were working on them. There it was. All these data ready for analysis. A launchpad to astronomical discovery in a brand new field. But she needed to set aside her work on active galaxies and scoop up all this amazing data on disks and really run with it.
So that's what she did.
In 1999, Weinberger published her first results on circumstellar disks. Few disks had been imaged before that. Her images suggested that disks weren't just smooth distributions of orbiting dust. Instead, she saw complex structures—with rings and spirals—and found there was no simple explanation for that. To see these structures meant there were many processes going on in disks that astronomers hadn't really thought through. Clearly, disks were not all the same. That is what really got her started on the path of trying to understand planet formation and what circumstellar disks can tell us about it in more detail, Weinberger says.
Two decades later, now-DTM astronomer Alycia Weinberger talks about circumstellar disks, the importance of curiosity, and what it means to seize the opportunities life throws our way.
Alycia Weinberger at Carnegie's Las Campanas Observatory, a place she says she loves to go to observe because of its amazingly great telescopes and beautiful skies. Photo courtesy of Alycia Weinberger.
Alycia Weinberger at Carnegie's Las Campanas Observatory, a place she says she loves to go to observe because of its amazingly great telescopes and beautiful skies. Photo courtesy of Alycia Weinberger.
DTM: What is the ultimate goal of your research?
AW: It's understanding our place in the universe. We think we're really special, but that is a very non-Copernican view of the universe, right? The history of astronomy has been about teaching humans that we aren't at the center of anything. The Earth isn't at the center of the solar system. The sun isn't the center of the galaxy. Our galaxy is just one average galaxy amongst others. But we'd still like to know how common life is in the galaxy, and in order to understand that, we need to know how common the kinds of planets that can host life are and how common the conditions that form those planets are. So I really see the whole project of planet formation and planet discovery as being a question of, "How unique are we, and what is our place in this vast cosmos in which we live?"
What's your favorite thing about being an astronomer?
Well I think it's always fun when you make a new discovery, and that's true for any science. I think finding puzzling data is also fun.
For example, last year former DTM postdoc Jessica Donaldson and I measured the distances to a lot of young stars in a nearby group of young stars. When I selected our targets, I chose equal numbers of stars that still had disks (that is, the raw materials for planets) and stars that didn't. One of the questions I was interested in was: Is there an age difference between those two sets of stars? We think disks go away with time, so my expectation when I designed the project was that the stars with disks would be younger than the stars without disks. But what we actually found was that stars without disks were, on average, the younger stars, and the stars with disks were a little bit older. This was completely unexpected. It's common to be surprised, but maybe not as blatantly as this.
My current favorite idea for explaining our finding is that we're seeing the impact of a really important process: Magnetic fields acting as an "anti-aging cream" for stars. So, the stars without disks aren't really younger, but just appear that way. We just found this intriguing result, I have a hypothesis, and now it is something I have to test.
DTM's Alycia Weinberger uses ground and space telescopes to study disks around young stars such as the ones shown here from her research. Disk images courtesy of Alycia Weinberger.
How did you end up doing research on circumstellar disks?
I was lucky. I actually switched topics between my PhD and my postdoc. And I hadn't necessarily intended to. As a graduate student, I was interested in active galaxies, which are galaxies with massive black holes at their cores consuming material at a rate sufficient that they can put out as much luminosity as all the stars in the galaxy combined. But other galaxies also have massive black holes that are not active. I was interested in what controls whether a black hole is active or not and how you feed material into the vicinity of a black hole to make it active.
I had intended to continue that research as a postdoc when I went to work with Erick Becklin at UCLA. He was part of the science team for a brand new instrument launched on the Hubble Space Telescope called NICMOS. The various groups within that team had data on all kinds of topics, and other people were analyzing the active galaxy data by the time I started working on the project. And Eric, who is an extremely broad scientist who's done research on a huge range of astronomy, was very interested in disks and brown dwarfs around other stars. Nobody was really working on the disk data, so there was a great opportunity to just jump in and explore all these data.
What are the milestones of your career?
Soon after I started graduate school, I got a chance to go on my first observing run at the 200-inch Telescope at Palomar Observatory in California. I had been reading about the 200-inch since I was a kid. I was fascinated by how difficult it had been to build the world's largest telescope, and how successful it had been. So in my mind, the 200-inch was the apotheosis of telescopes. I couldn't imagine anything more exciting than going to observe there. I remember thinking that was the culmination of my life. What could have been better? Now, I don't think that was actually the culmination, but I would say that was a huge moment for me. Actually, I've loved every large telescope I've observed on since!
I think the big serendipitous things in my career were choosing my advisors well, even though I didn't necessarily know much about how to do that. My PhD advisor, Gerry Neugebauer, gave me many opportunities and forced me to develop independence. My postdoctoral advisor had been his student, so I definitely benefited from the "old boys network." That turned out to be tremendously serendipitous because he had all the disk data and was an inspiring person to work with. These people shaped my career in substantial ways that I didn't know to expect.
What do you think is the most challenging aspect of your research?
The challenge of all astronomy is that the objects we are interested in are far away. Except for gravitational waves, which now have been detected from extremely distant objects, light is the only messenger that we have to bring us information. So we have to figure out how to make the best possible use of it at all wavelengths that come to us. That's a technical challenge: to have the right instruments or to build them. It's also a data analysis challenge because we need to separate, for example, the very bright starlight from the disk or a planet that we're actually interested in.
The computer revolution of the last 20 years has really helped, because now we can do the kinds of computations that used to take forever or be impossible. If you want to correct in real time for Earth's atmosphere every thousandth of a second, you need a computer that can keep up with that. Even for future space telescopes, we want to be constantly measuring the distortion of the telescope and correcting it.
I actually did my PhD thesis using a very computer-intensive technique, and I used what then was the world's fastest computer at Caltech to do my calculations. Now I can do those calculations on my desktop.
DTM's Alycia Weinberger and one of the twin 6.5-meter Magellan telescopes at Carnegie's Las Campanas Observatory in Chile. Photo courtesy of Alycia Weinberger.
What do you think are the biggest challenges of the scientific community?
We have to convince the American people to care about science. As wonderful as Carnegie and its endowment are for sustaining my science, the total budget of American science vastly exceeds what individuals are willing to support. We need public support for science, and I firmly believe that science has returned to the American public amazing dividends. But we have to advocate to Congress and to our fellow citizens that science should be a priority in our nation with commensurate funding. We need people to understand that what we do challenges the limits of our imagination and inspires us to advance technology. It's distressing to see climate change denial and belief in conspiracy theories—a lot of evidence of anti-scientific thinking.
What do you think is a definition of a really good scientist?
I once had someone say to me, "Oh, I had no idea scientists were so creative." I think creativity for solving problems is what makes a good scientist. That's probably true in any field, but I think that is something underappreciated about scientists. Solving puzzles takes creativity. Coming up with new projects takes creativity.
One thing I've been pleased to see is that science communication has improved. I think there were a lot of scientists when I was a student who took pride in doing work that was so difficult that it was hard to explain to people. But I think that understanding that we rely on public support for science has led to an improvement in science communication and to scientists who feel responsible for communicating their work succinctly and clearly to non-scientists. We scientists benefit from better communication with each other, too.
How do you think those qualities can help the scientific community face its challenges?
It's really important to convince young people that science is interesting and to engender an appreciation for it. I'm a skeptic about most things I hear, and I think my kids pick up on that. They know they shouldn't believe in just anything or any source. They should ask questions and take a second look at how we know if something is true or not. My kids are naturally skeptical now, which means they never really believed in the tooth fairy. They thought, "How come mom doesn't believe in anything magical but has this weird fascination with the tooth fairy?" They didn't realize I just loved to try to trick them with some late night sneakiness.
Was that environment similar to how you grew up?
People often ask me how I got interested in astronomy, and I have a stock answer to this, which is, when did you stop being interested in astronomy? I ask this because pretty much every kid I've met is interested in astronomy, so that is always kind of a puzzle to me. When do kids lose their natural sense for curiosity? Curiosity seems innately human to me. But, yes, I do have to give my parents a lot of credit for encouraging my curiosity and having me play with toys based on physical principles (Lego, marble runs, circuits, and the like).
What is the coolest science fact you know?
If you ask me this tomorrow, my answer will probably be something different. But it's amazing that the closest star to the Sun (Proxima Centauri) has a planet around about the same mass as the Earth. Really, planets must be so darn common. Because otherwise, what are the odds that the closest star to the sun has a planet very similar to the Earth, in mass and probably in temperature?
What do you think are the most fascinating mysteries out there?
I think the brain is really interesting. One of the humbling things as a parent has been to see how my kids develop differently and have different innate skills and personalities, perhaps despite my best attempts to guide them. Also, how do we humans have the ability to be creative, to think of things that no one has ever thought of before? I find that to be a really intriguing mystery.
Would you rather travel 1000 years to the future or into the past?
I would travel to the future. We know a lot about the past. Probably not enough, but I think I would be happy to live in the 22nd century, with its advances in knowledge, medicine, computer capabilities, and visualization.
I'm also optimistic and think there will be many exciting discoveries in the future. I always think about eminent Carnegie staff scientist Vera Rubin. She was very humble about astronomical discovery. She always said that we think we've learned so much when we look back on the astronomers of 400 years ago, and there's no reason to think that astronomers 400 years from now won't feel exactly the same way about us.
What's the next step for you?
I'm excited about the Giant Magellan Telescope (GMT), which in 10 years could be really powerful for studying planet formation. I've been working on a science book that describes all the fabulous science that the GMT can do, such as measuring the atmospheres of nearby planets. Ten years from now, things could be really different, with whole new projects to detect new planets and study them in ways we're just beginning to consider.
It's always fun to work on the next largest telescope, right? I thought this amazing moment in my life was at Palomar Observatory, which then had the world's largest telescope. Then, as a graduate student and postdoc, I got to use the Keck telescope, the new world's largest. A big part of my PhD thesis came from Keck data. So, I want to use the next one! How lucky is it if in your life you get to use three of the world's biggest telescopes in succession? That would be pretty awesome.
—Roberto Molar Candanosa, Carnegie DTM