What Is An Annular Solar Eclipse?

TIME

The 2023 eclipse is an annular solar eclipse, which occurs when the moon is farthest away from the Earth. A “ring of fire” will be created in the sky when the eclipse reaches its peak on Saturday.

Transcript

00:00 The moon, the earth, and the sun are all going around in space, right?

00:07 And so earth is orbiting around the sun.

00:10 Meanwhile, the moon is going around earth.

00:13 And sometimes we all just by chance kind of line up in a line.

00:23 So I'm Morgan McLeod.

00:24 I'm an astronomer at the Harvard Smithsonian Center for Astrophysics in Cambridge, Massachusetts.

00:30 So a solar eclipse is when the moon in the sky blocks all or part of the sun.

00:38 And we have an eclipse coming up this fall on October 14, 2023.

00:43 It's what's called an annular eclipse.

00:46 Annular means ring.

00:47 And so what's going to happen is that the moon is going to cross perfectly in front

00:53 of the sun.

00:54 And something you may have noticed is both the moon and the sun look about the same size

00:59 in our sky.

01:01 And that's not because they're the same size.

01:04 They're different sizes and different distances away.

01:06 So the moon is much closer and much smaller.

01:09 And the sun is much bigger and much further away.

01:11 They're about a half degree in angle.

01:14 It's about the size of a fingernail on the sky.

01:17 What that means is that the moon is about the right size to block the sun if it's lined

01:24 up just right.

01:27 A total eclipse is when the moon is perfectly blocking the sun on the sky and it completely

01:34 blocks the glowing hot disk of the sun.

01:38 And all we see is the atmosphere around the sun.

01:43 We're seeing the sun's extremely hot million degree atmosphere.

01:48 It's actually hotter than the surface of the sun.

01:50 The surface of the sun is about 5,000 degrees, but its atmosphere is close to a million.

01:56 An annular eclipse is what would be a total eclipse, but it's at its furthest point in

02:03 its orbit.

02:04 It's closer to 400,000 kilometers away than its average of 380,000.

02:11 It's a little bit too small to cover the entire sun.

02:16 And what we'll see instead is a ring of bright sun around the outside and most of the sun

02:23 blocked out by the moon.

02:25 When you see that with just your eyes, you know, the sun is so bright, it's hard to see

02:29 what's going on.

02:30 But if you have either a pinhole projector or eclipse glasses, you can see a perfect

02:36 ring of lit up sun just behind the moon.

02:42 And so unlike a lunar eclipse where you can see anywhere that it's nighttime, a solar

02:46 eclipse, you have to be just in the right spot on the earth.

02:51 And so people will travel all over the earth just to be in the path of a solar eclipse.

02:56 The path of the moon blocking the sun is narrow on earth.

03:00 And so it's a narrow path that will see a total eclipse, a much bigger path that will

03:05 see a partial eclipse.

03:07 So even if an eclipse is total somewhere, it's partial somewhere else.

03:12 So just being a few cities away might be enough that you're not like aligned enough and you

03:20 would see a partial instead of a total eclipse.

03:24 Now to get that kind of perfect alignment with a perfect ring, you have to be right

03:29 in the path of that.

03:31 The path of that eclipse, it passes through Texas, for example, where I live in Massachusetts,

03:36 we'll see a partial eclipse.

03:38 So the moon will miss a little bit, but it'll partially block out the sun's light.

03:44 And the part where the moon perfectly blocks out the sun is only a couple of minutes long.

03:52 But it's supposedly a completely amazing moment because rather than just our sun's normal

04:00 bright disk, you get to see its hot outer atmosphere that's normally glowing.

04:06 Most of that energy is coming off as x-rays and you see it's sort of stringy outer atmosphere.

04:12 For just a moment, it becomes night in the middle of the day and all the animals react

04:17 and it's this kind of amazing thing.

04:19 (music)

04:21 (silence)

04:23 [BLANK_AUDIO]

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