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For an ad free listening experience,

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A link can be found in our show notes. Thank

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you you're

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listening to sleep Tight Science.

0:39

Did you know that the Moon's

0:41

shadow races across the Earth's

0:44

surface at super speeds of

0:46

up to one seven hundred kilometers

0:49

per hour about one fifty

0:51

six miles per hour. What that's

0:55

even faster than the speed of sound. Hello,

1:11

friends, and welcome back to Sleeptight

1:14

Science, a bedtime show that answers

1:16

your questions about science.

1:21

Did you know that on April eighth,

1:24

twenty twenty four, North

1:26

America will witness a total

1:28

solar eclipse as it travels

1:30

across Mexico, the United

1:33

States, and Canada.

1:37

This occurs when the Moon moves directly

1:40

between the Earth and the Sun, fully

1:43

covering the Sun's face. As

1:46

this happens, the sky will turn

1:48

dark, mimicking the light of early

1:50

morning or late evening. Eclipses

1:55

are really special because they don't happen

1:57

all the time and you need

1:59

to be in the right place on Earth to

2:01

see them. We will

2:04

experience it where we live at about

2:06

four forty PM and are

2:08

very excited. According

2:13

to NASA, the next total

2:15

solar eclipse will occur on August

2:17

twelfth, twenty twenty six, visible

2:20

in Greenland, Iceland, Spain,

2:23

Russia, and a small portion of

2:25

Portugal. In

2:28

Canada, the next time a solar

2:30

eclipse will be visible will be in twenty

2:32

thirty nine, when the path of

2:34

totality passes through the

2:36

northern part of the Yukon. But

2:42

what is a solar eclipse? A

2:45

solar eclipse occurs when the

2:48

Moon passes between the Earth and

2:50

the Sun, temporarily blocking

2:52

the Sun's light from reaching us. This

2:56

can turn day into night, cool

2:58

the air, and reveal the Sun's

3:01

outer atmosphere, known as the

3:03

corona, which is usually

3:05

invisible to the naked eye.

3:09

To understand how a solar eclipse

3:12

has happens, we need to look at the mechanics

3:14

of our solar system.

3:17

The Earth orbits around the Sun,

3:19

and the Moon orbits around the

3:21

Earth. While these

3:24

orbits are happening, there are

3:26

moments when the Earth, the Moon,

3:28

and the Sun a line or line

3:31

up perfectly. When

3:35

the Moon positions itself directly

3:38

between the Sun and the Earth, it casts

3:40

a shadow on the Earth's surface. This

3:43

shadow is what we experience as

3:46

a solar eclipse. Put

3:49

another way, the Earth is like a big

3:52

ball that spins around the Sun, and

3:54

the Moon dances around the Earth.

3:57

Every now and then, the Moon, the Earth,

4:00

and the Sun line up perfectly. When

4:03

the Moon gets right in the middle, it blocks

4:06

the Sun's light from reaching us, causing

4:09

a solar eclipse. During

4:14

an eclipse, two shadows

4:16

are cast. The first

4:18

is called the umbra. This

4:21

shadow gets smaller as it goes

4:23

away from the Sun. It

4:26

is the dark center of the eclipse

4:28

shadow. The

4:31

second shadow is called the panumbra.

4:34

The penumbra gets larger as

4:36

it goes away from the Sun. The

4:40

umbra, the inner, darker part

4:42

of the shadow, is where the Sun is completely

4:45

blocked by the Moon. Observers

4:48

in the path of the umbra experience

4:51

a total solar eclipse, turning

4:54

the day into a brief night. The

4:57

sky darkens significantly, stars

5:00

and planets become visible, and

5:02

the temperature drops. The

5:04

corona, a halo of plasma

5:07

that surrounds the Sun, becomes

5:09

visible, displaying a

5:11

beautiful glow.

5:15

The penumbra is the outer part

5:17

of the Moon's shadow, where the

5:19

Sun is only partially obscured.

5:23

Observers in this area see

5:25

a partial solar eclipse,

5:27

during which the Sun appears as if a

5:29

bite has been taken out of it. The

5:32

effect is less dramatic than a total

5:35

eclipse. The

5:43

reason we don't experience a solar

5:45

eclipse every month, even

5:47

though the Moon orbits the Earth monthly,

5:50

is due to the tilt of the Moon's

5:53

orbit. The

5:55

Moon's orbit around the Earth is tilted,

5:58

leaning about five degrees to

6:00

the Earth's orbit around the Sun. This

6:04

means that the Moon usually passes above

6:07

or below the Sun from our

6:09

perspective on Earth, A

6:12

solar eclipse occurs only

6:15

when the orbits line up just

6:17

right and the Moon is near

6:19

one of its two crossing points

6:21

with the Earth's orbital plane,

6:24

known as nodes. Solar

6:29

eclipses can only occur during

6:31

a new moon, when the Moon is between

6:34

Earth and the Sun. However,

6:37

not every new moon results

6:39

in a solar eclipse. The

6:42

precise alignment necessary

6:44

for an eclipse happens just

6:46

a few times a year. A

6:54

total solar eclipse goes

6:56

through several unique stages.

6:59

It begins with a partial eclipse

7:01

phase, where the Moon starts

7:04

to move in front of the Sun, partially

7:06

covering it and creating a crescent

7:09

shape.

7:11

Then comes Bailey's beads

7:13

face, where the Sun's light

7:15

peaks around the jagged edges of the

7:17

Moon due to its uneven surface,

7:20

creating a string of bright spots.

7:25

Following this, the diamond ring

7:27

phase occurs, when a single

7:29

bright point of light shines

7:32

beside the Moon while the Sun's

7:34

atmosphere forms a glowing circle

7:36

around it, looking much like

7:38

a sparkling diamond ring. This

7:43

stunning visual signals the approach

7:46

of totality after

7:48

the moment of total eclipse. These

7:51

stages happen in reverse as

7:53

the Moon continues on its path

7:56

leading up to the end of the eclipse.

8:02

Eclipses are really special because

8:04

they don't happen all the time and

8:06

you need to be in the right place on Earth

8:08

to see them.

8:12

Eclipses have fascinated us for

8:14

millennia, inspiring awe,

8:17

fear, and curiosity.

8:20

Ancient civilizations often

8:22

interpreted eclipses as omens

8:25

or messages from the gods. Today,

8:29

solar eclipses continue to

8:31

attract attention from scientists

8:33

and the public alike, offering

8:36

opportunities for scientific study,

8:39

photography, and personal

8:41

reflection. You might

8:43

want to listen to our episode called

8:46

Our Solar System to learn more

8:48

about the Solar system.

9:08

Experiencing a solar eclipse

9:11

can be super exciting, but

9:13

you have to be very careful not to hurt

9:15

your eyes. The sun

9:18

is incredibly bright even

9:20

when partly hidden by the moon. If

9:23

you look at it without protection, the

9:26

strong sunlight can damage your eyes

9:29

and you might not even feel it happening.

9:33

So how can you watch a solar

9:35

eclipse without hurting your eyes? Here

9:38

are some safe ways. You

9:41

can use special eclipse glasses.

9:44

These aren't your regular sunglasses.

9:47

They're super special glasses made

9:49

just for looking at the sun. They

9:52

have a special film that blocks out

9:54

the harmful rays so you can

9:56

look at the eclipse safely. You

10:01

can use a pinhole projector. This

10:04

is a fun DIY project and

10:06

one we are going to try.

10:09

You and your family can make a simple

10:11

pinhole projector with just

10:13

two pieces of card. Make

10:16

a tiny hole in one piece, then

10:19

let the sun shine through that hole

10:21

onto the second piece of card. You'll

10:24

see a mini eclipse happening

10:27

right on your card.

10:31

You can use a colander. If

10:33

you have a colander in the kitchen, you

10:35

can use it to see the eclipse. A

10:38

colander is a kitchen tool that looks

10:40

a bit like a bowl with lots of little

10:43

holes in it. People use

10:45

a colander to rinse fruits and vegetables

10:47

under water, or drain water from

10:50

things like pasta or cooked vegetables

10:52

after boiling them.

10:55

Hold the colander up to the sun during

10:57

the eclipse and you'll see lots

10:59

of little crescent suns projected

11:02

onto the ground or a wall. Remember

11:06

never look at the sun directly

11:08

with a telescope, binoculars,

11:11

or camera unless they have special

11:13

solar filters. Even

11:16

with eclipse glasses, you should

11:18

only take quick glances at the Sun,

11:21

not stare at it for a long time. Did

11:29

you know the Sun is actually white

11:32

When we look at it from Earth. The atmosphere

11:35

scatters the light, making the Sun

11:37

appear yellow, But if

11:39

you saw it from space, it would

11:42

look dazzling white.

11:47

Now for some listener questions. Our

11:50

first question is from Adeline Harmon,

11:53

who is seven years old and lives

11:55

in Anchorage, Alaska.

11:58

Adeline wants to know how the Northern

12:00

lights appear. The

12:03

Northern lights, also known as

12:05

the Aurora borealis, are

12:07

a magical light show in the sky

12:10

that can be seen most easily near

12:12

the North Pole. They look

12:14

like big curtains made of light, gently

12:17

waving back and forth. These

12:20

lights can be green, pink, purple,

12:23

blue, and sometimes even red.

12:27

They can look like soft, glowing clouds

12:30

or sharp streaks of color that light

12:33

up the night. Here's

12:35

how the beautiful spectacle happens.

12:38

The Sun sends out a stream of charged

12:41

particles, like an invisible

12:43

wind blowing through space. This

12:46

wind is called the solar wind. When

12:50

it reaches Earth, it bumps into

12:52

our planet's magnetic field, which

12:55

is like an invisible shield that protects

12:57

us. The Earth's

12:59

magnetic field has weak spots

13:01

near the poles, so some

13:03

of the charged particles from the Sun can

13:06

sneak through there. When

13:09

these particles hit the gases

13:11

in our atmosphere, they light

13:13

up, just like a neon sign.

13:16

Different gases light up in different

13:19

colors. Oxygen gives

13:21

us greens and reds, while nitrogen

13:24

can make pinks and purples. The

13:27

Northern lights usually happen in a ring

13:29

shaped zone around the north pole, but

13:32

when there's a lot of solar activity,

13:34

they can be seen farther south than usual.

13:38

So the northern lights are a bit like

13:40

a natural light show put on by

13:42

the Earth and the Sun, and

13:44

they're one of the most beautiful things

13:47

you can see in the sky. Thank

13:50

you for the question, Adeline. Our

13:54

next question is from Nate, who

13:56

is seven years old. Nate

13:59

asks why is lightning so

14:02

hot. Lightning

14:04

is super hot because it's a

14:06

powerful electric current racing

14:09

from the clouds to the ground or

14:11

sometimes inside the clouds.

14:15

When this electric current zaps

14:17

through the air, it heats the air up

14:19

very very quickly. This

14:23

happens because the electric current

14:25

is so strong and fast that

14:27

the air doesn't have time to move out of the

14:29

way, so it gets squeezed

14:32

and heated up to about twenty thousand

14:35

to thirty thousand degrees celsius.

14:38

That's thirty six thousand to fifty

14:40

four thousand degrees fahrenheit, hotter

14:43

than the surface of the sun. When

14:46

the air heats up so much and so

14:49

fast, it creates a bright

14:51

flash of light, which we see

14:53

as lightning. The

14:55

superheated air expands

14:58

explosively, which we hear

15:00

as thunder. So

15:02

lightning is hot because of the intense

15:05

electric energy passing through the air,

15:08

heating it up to incredible temperatures

15:11

in the blink of an eye.

15:14

Thank you for the question, Nate. Did

15:20

you know that rainbows are circular?

15:23

We usually see rainbows as arches,

15:26

but they're actually full circles.

15:29

The ground usually blocks the bottom

15:31

half, so we don't see it. You

15:34

might be lucky enough to see a rainbow's

15:37

full circle if you are high enough,

15:40

like in an airplane.

15:45

Our last question comes from Isaiah,

15:48

who is six years old and from Texas.

15:52

Isaiah asks why is the sky

15:54

blue.

15:57

The sky is blue because of something

16:00

called scattering. When

16:02

sunlight reaches the Earth, it has

16:04

to pass through the air in our atmosphere.

16:08

Sunlight might look white, but it's

16:10

actually made up of all the color of

16:12

the rainbow mixed together. As

16:16

sunlight comes down, it bumps

16:18

into the tiny bits of air and water

16:20

in the atmosphere. Different

16:23

colors in the sunlight have different energies

16:26

and scatter in different ways. Blue

16:29

light has shorter waves and more energy,

16:32

so it gets bumped and scattered all

16:34

around the sky by the air. This

16:37

scattering sends blue light everywhere,

16:40

and when we look up, that's the color

16:42

we see. The other

16:45

colors like red and yellow, have

16:47

longer waves and don't get scattered

16:49

as much in the lower atmosphere, so

16:52

they keep going straight. That's

16:55

why the sky isn't red or yellow during

16:57

the day, but at

16:59

sunrise and sunset, the

17:01

light has to travel through more air to

17:03

reach your eyes, making the blue

17:06

and green light scatter out even more,

17:08

leaving the reds and oranges for us

17:11

to see. That's why

17:13

sunsets are red and orange,

17:15

not blue. So

17:18

the sky is blue because the blue light

17:20

from the sun gets scattered in all

17:23

directions by the air and our

17:25

atmosphere, and that's what reaches

17:27

our eyes the most. Thank

17:31

you for the question, Isaiah.

17:37

Now for some fun facts. Did

17:40

you know the moon is not perfectly

17:42

round. It's actually

17:45

shaped a bit like an egg, with one

17:47

end slightly flattened and the other

17:49

more pointed. This is

17:51

because of the gravitational forces

17:54

between the Earth and the Moon. Did

17:59

you know the Sun is so big that

18:02

about one point three million

18:04

earths could fit inside it. If

18:07

the Sun were a hollow ball, you

18:09

could neatly pack all those earths

18:12

in inside and still have room

18:14

for more. Did

18:18

you know some satellites are really

18:20

small. There are cube

18:23

sacts, which are tiny satellites

18:25

as small as a loaf of bread. That's

18:28

pretty small.

18:30

Despite their size, they can

18:32

do serious science, test

18:35

new technologies, and even teach

18:37

students about space. Did

18:43

you know the Moon is slowly moving

18:45

away from the Earth each

18:48

year, it drifts about three point

18:50

eight centimeters about one point

18:52

five inches further away. This

18:55

means that very very slowly, the

18:58

Moon is getting farther from us. And

19:02

for something different, did you know

19:05

that the world's largest chocolate chip

19:07

cookie weigh as much as an elephant?

19:11

In two thousand three, the Immaculate

19:14

Baking Company in South Carolina

19:16

baked a cookie that was one hundred

19:18

and two feet wide and weighed

19:21

over forty thousand pounds.

19:24

That's a big cookie.

19:27

Do you think you would want to eat it? In

19:33

this episode, we learned a little about

19:35

solar eclipses. A

19:37

solar eclipse occurs when the Moon

19:40

passes between the Earth and the Sun,

19:42

temporarily blocking the Sun's light

19:44

from reaching us. This

19:47

can turn day and to night, cool

19:49

the air, and reveal the Sun's

19:51

outer atmosphere, known as the

19:53

corona, which is usually invisible

19:56

to the naked eye. Two

20:00

shadows are cast when there is a solar

20:02

eclipse. The first, the

20:04

inner shadow, is called the umbra,

20:07

and the second, the outer shadow,

20:09

is called the panumbra. There

20:12

are safe ways to look at a solar eclipse,

20:15

but you should never stare at the sun. There

20:19

are special eclipse glasses or

20:21

you could make a pinhole projector or

20:24

use a calander to reflect it on your

20:26

wall or floor. We

20:28

had questions from Adeline Harmon

20:31

who wanted to know how the Northern lights

20:33

appear, Nate who asked

20:35

why is lightning so hot? And

20:37

Isaiah who asked why is

20:39

the sky blue? Thank

20:44

you to Jesse who is four years

20:46

old, Liam

20:48

Max Christensen who is four and a half

20:51

years old and lives on the North Island

20:53

of New Zealand, Alblow

20:56

in Scotland who is five years old,

20:59

Sophia Harmon five years old,

21:02

and Amelia Harmon seven years

21:04

old. The Thompsons

21:06

in Manhattan Beach, California,

21:09

Harrison Gryce in Germany, Caylee

21:12

of Nelson Case

21:14

age eight, Jesse

21:17

who is four years old from Brazil, Rohan

21:20

who is four years old from Maryland,

21:23

Elizabeth Frey from San Anselmo,

21:26

California, who is five years

21:28

old, Holland

21:30

from White House, Texas, Emily

21:34

Abigail Claire who is five years

21:36

old in Lubbock, Texas, and

21:39

Zara.

21:42

We would love to get your feedback on our

21:44

show. If you have any feedback,

21:46

please send it our way. If

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you want to make sure you get all the episodes

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22:01

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22:03

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22:11

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22:16

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