MARY LOUISE KELLY, HOST:
The path of a total solar eclipse passed over a major observatory in Chile this afternoon. NPR science correspondent Joe Palca was there. He saw the eclipse from the Cerro Tololo Inter-American Observatory from where he joins us now live.
JOE PALCA, BYLINE: Hey, Mary Louise. How are you doing?
KELLY: I'm well. Thank you. And I'm thinking, I have actually - I have seen a couple of total solar eclipses. I have never seen one from an observatory, which I'm guessing is a pretty darn good place to see one.
PALCA: Well, since I've never seen one before, I can't tell you whether it's better or worse. But I can tell you it's pretty stunning. I mean, I'm at 7,000 feet. And you know that what happens is the shadow - or the moon, you can watch it sort of creep across the face of the sun. And then eventually, it gets to block the whole sun out.
But just before that happened, you could see a wall of shadow moving over the ocean, which we can see from the mountains here, toward the mountaintop, over the town of La Serena, which is along the coast, and then over the lower hills up to the side of the mountain. And then all of a sudden, you look up, and there is the sun with this bright circle of light around it. And - they call them Baily's beads. They're these amazing, like - I don't know - ball bearings or something made out of light. And it's just - it was just stunning. You know...
KELLY: You've still got the shivers, I can...
PALCA: ...I'm speechless.
KELLY: (Laughter) You're not quite speechless. But blown away, it sounds like.
PALCA: Well, pretty much.
KELLY: In terms of why scientists were there and watching all this, what are they hoping to learn from this particular eclipse?
PALCA: Well, you know, there's only a few times when you can see that thing called the corona, which is the outer atmosphere of the sun. It's an interesting thing. It's powerful gases that are heated even hotter than the surface of the sun. And scientists would like to know more about it, not just, you know, what's in it, which is interesting, but how it changes over time and what it tells you about the magnetic field of the sun.
And also, you know, these are the - inside these - this corona, the particles that cause the solar wind that then affect the Earth and can affect the Earth and disrupt communications and electrical signals, they'd like to know more about that so they understand better how to predict space weather essentially.
KELLY: And tell me more about who you're watching with, this observatory where you are. You said you're 7,000 feet above sea level.
PALCA: Right. We are at - this is an observatory. It's got several telescopes. The one that is right here at Cerra Tololo made the observations that told the world that there was such a thing as dark energy, which was not even known before 1998, and in 2011 earned the discoverers a Nobel Prize. It's a force that's making the universe expand rather than contract. And so that was unknown. And it was - and the stars that proved it - the supernova that proved it were discovered here.
On the other mountain right nearby, Cerra Pachon, they're building the next generation of telescopes. It's called the LSST - great name - a Large Synoptic Survey Telescope. And that will be something that will - it will look at the entire sky and essentially look for things that go bump in the night, things that change from one night to the next that might indicate a planet or an asteroid or some star that's behaving in a way that nobody's seen before.
KELLY: Just briefly, Joe - what else have you got in store for your reporting trip down there? You came down for more than just the eclipse, I'm guessing.
PALCA: Well, yeah. I mean, Chile is an amazing place for observatories. And I'm headed off to the Atacama Desert, where they have several telescopes, including ALMA, which is the Atacama Large Millimeter Array telescope. And that's been making all sorts of interesting discoveries, as is a new set of telescopes that's trying to look for the origins of the universe. So that should be interesting.
KELLY: I think you're officially winning the have more - having-more-fun-than-the-rest-of-us award for the day. NPR science correspondent Joe Palca, thank you.
PALCA: You're welcome. Transcript provided by NPR, Copyright NPR.