DAVID GREENE, HOST:
Well, today, one of those events that can turn us all into science nerds - we're going to be wearing these weird-looking glasses and looking up at a solar eclipse. That is, a total eclipse is sweeping its way across the U.S. from Oregon to South Carolina. And millions of Americans have been just enduring bad traffic and back roads to get into this path of totality. But the partial eclipse is going to be visible everywhere. I'm in Southern California. Ailsa, I can see you in Washington, D.C., on a video screen.
AILSA CHANG, HOST:
GREENE: You're with Joe Palca, NPR's science correspondent. Do you guys have your glasses? I mean, is this something you're doing?
JOE PALCA, BYLINE: Well, I have a set. I'm going to give mine to Ailsa so you can see.
GREENE: Oh, that'd be great. Yeah, we should say we have this video feed. So put them on. Oh, those are weird.
GREENE: That is science nerdy.
PALCA: Now, Ailsa, if you can see me, there's something wrong.
CHANG: I cannot see anything. I feel like I have black construction paper in front of my eyes.
PALCA: That's basically it.
GREENE: You look like a character from "Star Wars."
PALCA: Yeah, pretty much. No, that's - there's a point to this, though, because that kind of glasses - no matter how dark a pair of sunglasses you have at home - they're not dark enough. These are special glasses for looking at the partial eclipse. And can I just say it's really important to understand that it's the partial eclipse that David and you and I are going to see if the sky's clear? That's dangerous for your eyes. Total eclipse - the sun is completely obscured. And during totality, that's the only time the only time - the only time - it's safe to look at the sun without glasses, without these special glasses.
GREENE: But, generally, everyone should err on the side of wearing these glasses. I mean...
PALCA: Yes, but not during the total eclipse because then you'll lose all the fun because that's the only time you can look at the sun, and you get this amazing light show, apparently, of the wispy atmosphere of the sun flickering around the sun.
GREENE: So just those moments for people who are actually in the path of totality...
PALCA: That's it.
GREENE: That's the only time to not have the glasses...
GREENE: So this is - timing, Joe - the sun rises in the east, but the eclipse is starting on the West Coast. That doesn't make sense to me.
PALCA: All right. Well, don't think about it too hard.
PALCA: Or get out your old models and, you know, your Earth with the moon running around it and the sun. But, yes, it's going to start - it's going to hit the West Coast at 1:16 - thereabouts - Eastern Time. Although, actually, if you happen to be in a boat out in the Pacific, you'll be able to see it about a half an hour earlier.
GREENE: Oh, good.
PALCA: (Laughter) And it exits the East Coast of the United States around 2:49-ish. But then you've got another - I don't know - almost 40 minutes or so - almost 40 minutes out into the Atlantic. It reaches almost all the way to Africa. But it won't quite get to Africa.
GREENE: And what about weather? I mean if it's cloudy, does that just mess everything up?
GREENE: Pray for clear skies.
PALCA: Exactly. It's looking good in the western United States. I'm told that the weather service is reporting good-looking for Nashville, Tenn., Paducah, Ky. - a little more iffy in other parts of the country. You're just going to have to play it by ear. Is that right? No.
GREENE: I think ear. Yeah, play it by ear. You'd be a great weatherman.
GREENE: I mean, you sound great. So I mean - but if it's cloudy, it'll still get dark, right?
GREENE: Like, we'll experience something.
PALCA: Yes, you will - the sky will get very, very, very dark.
GREENE: OK. So even if you're in a cloudy place, don't worry. It'll feel weird and wonderful. This is the big day of the eclipse. Just wear those glasses.
GREENE: That was NPR's science correspondent, Joe Palca. Joe, thanks.
PALCA: You betcha. Transcript provided by NPR, Copyright NPR.