An astronomer hunts galaxies on the darkest mountain in Chile

Interview: OWEN MYERS

Owen Myers: What’s it like working in Cerro Tololo, one of the darkest places on earth?

Kathy Vivas: It’s fantastic for astronomers, that’s why we built the Cerro Tololo Inter-American Observatory here! The light we study comes from galaxies millions of light years away and is very dim, so only in very dark places are you able to record photos of it.

OM: Is it rare to find a place on earth which is this dark?

KV: It is. Most cities have a lot of light, and that’s not good for doing astronomy. Much of the world’s population has never seen a sky full of stars, or the Milky Way, because you can only see them from very dark places.

OM: How does it feel to look at the Milky Way without a telescope?

KV: It’s just amazing. I’ve observed hundreds of times here, but I don’t get tired of it. Even when I’m working inside on the computer, I always go outside to see the Milky Way.

OM: What’s the most amazing thing you’ve seen since working here?

KV: We discovered 20 very small satellite galaxies around the Milky Way, using our Dark Energy Camera. These are tiny galaxies, so small that they are called "ultra-faint dwarf galaxies".

OM: What’s dark energy?

KV: That’s one of the biggest questions that we have in astronomy today. We know that the universe is expanding. We also know that there is something that is accelerating the universe’s expansion, but we don’t know what that is yet.

OM: Is it called dark energy because it has no light?

KV: The name “dark” is more because we don’t know what it is. But it doesn’t interact with light, so we can’t see it.

OM: What first captured your imagination about the world of astronomy?

KV: I am originally from Venezuela, and ever since I was a little kid, I’ve been captivated by a sky full of stars. I was in high school when Halley’s Comet came. And when my family took me to an observatory, I made the decision that I wanted to pursue astronomy as a career.

OM: And Cerro Tololo is an American operation?

KV: Yes, the observatory is funded by the National Science Foundation in the United States. In Chile, there are observatories from countries all over the world. I guess everybody discovered that we have the best skies.

OM: I heard that you were observing last week. How did that go?

KV: It actually didn't go that well! On two nights the sky was completely covered by clouds. It was bad luck.

OM: That's a shame. I'm curious, what do you think of the way that astronomy is depicted in movies?

KV: It's quite bad. In movies, the astronomer puts their eye directly on the telescope and is stargazing. No! That's not the way we do it. We observe the images on our computer, in a separate room.

OM: So, the romantic image of an astronomer gazing through a telescope is a bit naive and old-fashioned?

KV: Exactly.