AILSA CHANG, HOST:
Let's take a moment to appreciate science. No doubt you've been hearing all about the eclipse that'll be visible across America in about a week. But imagine someone thousands of years ago who saw the sun disappear and didn't know why.
ED KRUPP: It was bad news. And you can understand that. It's a reversal of the normal circumstances of the world and life. It's as if the whole cosmos is under threat.
CHANG: That's Ed Krupp, the director of the Griffith Observatory in Los Angeles. He's a veteran of 14 eclipses and counting. As a scientist, Krupp likes eclipses because of what he can learn from them. But science cannot explain all the appeal of an eclipse, like that moment when animals start to react.
KRUPP: You hear a silence develop where the birds stop singing, roosters and chickens go back to roost. And of course, people act wacky. Now it's exuberance and amazement and, in some people, a very strong emotional response. But you hear a lot of spontaneous yelling and shouting and exclamations.
CHANG: Can you describe - what does an eclipse look like?
KRUPP: The sky grows darker and, in fact, gets very dark at the time of totality, when the last bit of sunlight disappears and is extinguished by the disk of the moon. And you see the corona around the sun, this pearly, tremulous halo of more or less white light that you don't normally ever see with the sun because the sun's too bright. There are red flames, prominences that even the unaided eye can detect. And planets pop out. And the sun looks blacker than the sky around it.
CHANG: What do scientists hope to learn from this one that's coming up? I mean, is there still a lot about the sun we don't know yet?
KRUPP: There certainly are mysteries that remain about the sun. And just to give you an inkling about that, that corona, there's hardly any material there. There are atoms, of course, but there's not a lot compared to what's below it. And yet they're extremely hot. And so the question, once it was discovered, is, well, what in the world is heating this gas to such a high temperature?
And that question still remains incompletely answered. But in a total solar eclipse, that still is the one time to get critical physical data about what's happening in those zones. And that information is continuing to be used to try to come to a better understanding.
CHANG: What are some practical things that we can learn from an eclipse?
KRUPP: There is material being ejected by the sun in a huge mass of vents. And those high-energy particles travel to the Earth. If they intercept the Earth they can, in fact, disrupt the electromagnetic field of the Earth. And we've had major blackouts of the electrical grid regionally in the past because of these things.
And so observing the sun and eclipse, if that helps you understand how the sun works, you're going to be better able to adapt to the whims, in a sense, of this extraordinary star that we call the sun but, in fact, is a fury of thermonuclear energy pouring out of it and propelling high-energy radiation our way and elsewhere in the solar system.
CHANG: What makes you keep going back and witnessing all these eclipses?
KRUPP: Every eclipse is different. Every eclipse is extraordinary. It is, in fact, the most spectacular thing the sky does. The aurora borealis is a close second, but there's really nothing quite as amazing to people as the effect in its entirety of a total solar eclipse.
CHANG: That's Ed Krupp, the director of the Griffith Observatory. Transcript provided by NPR, Copyright NPR.