5 Questions for Astronomy Professor Alex Filippenko

Alex Filippenko, UC Berkeley Professor of Astronomy

Alex Filippenko is Professor of Astronomy and the Richard & Rhoda Goldman Distinguished Professor in the Physical Sciences at UC Berkeley. An elected member of the National Academy of Sciences, he has coauthored about 700 scientific publications and is one of the world’s most highly cited astronomers. He has received numerous prizes for his research, and was a member of both teams that discovered the accelerating expansion of the Universe, which was honored with the 2011 Nobel Prize in Physics to the team leaders. Winner of the top teaching awards at UC Berkeley and voted the “Best Professor” on campus a record eight times, he was selected as the National Professor of the Year in 2006. He has produced several astronomy video courses for The Great Courses and has appeared in numerous television documentaries, including about 40 episodes in The Universe series on The History Channel. He will speak on Dark Energy and the Runaway Universe on Tuesday, May 15 at 7:30 pm in the BBLC Lecture Hall.

Alex teaching at UC Berkeley

1. What is dark energy and the runaway universe?

In 1998, two teams on which I participated discovered that the expansion of the Universe is speeding up with time, rather than slowing down due to attractive gravity as had been expected. This discovery was honored with the 2011 Nobel Prize in Physics to the leaders of the teams. It’s thought that the acceleration is caused by gravitationally repulsive “dark energy” that fills all of space. If this dark energy continues to dominate, the Universe will expand faster and faster with time, ending in a “runaway Universe.”

2. Why did you decide to study astronomy? Why do you think it’s important?

I decided to study astronomy because I wanted to know how the Universe works as a whole, and how things like galaxies, stars, and planets form. I wanted to know where everything came from, including the chemical elements of which we are made. In a sense, astronomy is the study of our ultimate origins.

The bright white dot is a supernova, a very bright exploding star. The surrounding spiral pattern is the galaxy which contains the supernova. The picture on the right was taken several years later, when the supernova had faded. Credits: Lick Observatory image: W. Li and A. V. Filippenko (University of California, Berkeley); HST image: NASA, ESA, The Hubble Heritage Team (STScI/AURA), and A. Riess (STScI)

3. How did you get involved in your specific area of astrophysics?

In 1985, I discovered an exploding star (supernova) while conducting a study of the centers of nearby galaxies. This got me interested in supernovae in general: what kinds of stars explode, how they explode, what chemical elements they produce, etc. Well, it turns out that one kind of exploding star known as a Type Ia supernova is very powerful and usually quite uniform—that is, different Type Ia supernovae all have about the same peak power. This makes them very useful for determining the distances of very distant galaxies. Knowing the distances of galaxies and measuring their spectrum can tell us the expansion history of the Universe, and it’s from this type of study that we discovered the accelerating expansion of the Universe.

4. What advice do you have for students who are interested in entering your field?

Take a lot of math and physics courses, both in high school and in college. Study hard. But also don’t neglect reading and writing, because you have to understand a lot of technical writing in my field, and you must have the ability to express yourself clearly both to technical and general audiences.

5. If you could know the answer to one thing, what would it be?

I would like to know how the Universe began, what existed before it, and whether ours is the only universe. (Perhaps this sounds like three questions, but actually they are closely related so I think they count as one.)

Special thanks to Jon Bretan’s astrophysics students for coming up with these questions for Alex!


About Travis

Head of School, Marin Academy.
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