WEBVTT

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🎵 [music] 🎵

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KIDS: Our World!

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EVAN: Hey Globey, have you ever
done the hula?

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Why am I wearing a grass skirt?

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Because today we're going to
Hawaii!

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Well, we're not really, but we
are going to talk about

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some cool observatories in
Hawaii. Do you know what an
observatory is?

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That's right! Telescopes are
instruments that help make

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distant objects look larger and
nearer.

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And observatories are where
astronomers use telescopes to
look out into space.

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There are two basic types of
observatories.

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One is earth-based, which means
the observatory is located here
on Earth.

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The other is space-based, which
means the observatory

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is in outer space, such as the
Hubble Space Telescope.

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Hubble is one of the giant
telescopes that orbits Earth

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and sends back amazing pictures
of our universe.

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You can find Earth-based
observatories all over the

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globe, but today we're going to
talk about some special

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earth-based observatories in
Hawaii.

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Hawaii is our 50th state, and
it's made up of hundreds of

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small islands in the Pacific
Ocean.

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Some of the observatories here
are built on the Big

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Island of Hawaii on top of the
Mauna Kea summit.

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Mauna Kea is a Hawaiian name
that means the "white
mountain."

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But it's not just any kind of
mountain. It's a dormant
volcano crater.

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Dormant means the volcano is
not going to erupt anymore.

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High on this mountain,
astronomers from several

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different countries operate 13
of the world's most

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powerful Earth-based telescopes
of different kinds.

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Observers on Earth have to look
into space through Earth's
atmosphere.

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As light travels through the
atmosphere, it bounces off

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particles in the air and may
appear fuzzy.

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Clouds and city lights
interfere with the view as

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well, making faraway light hard
to see.

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So astronomers built these big
observatories on Mauna

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Kea to advantage of the high
altitudes.

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The summit, or very top of the
volcano, is so high up

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that it's actually free from
most of the pollution in the
sky.

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The air here is thinner or less
dense, so there are

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fewer particles to scatter the
light.

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Also, there is less water vapor
in the air here so

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there are almost never any
clouds covering the summit.

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Astronomers usually have a
clear sky to look into outer
space.

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And because the telescopes are
on an island, there is

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less light pollution, so
astronomers look out into an

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extremely dark sky to observe
some of the faintest far off
galaxies.

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Some of the observatories in
Hawaii use optical

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telescopes, which means they
see in "visual" light.

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DR. KELLY HERBST: Well light
comes in many different
varieties.

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We know about visible light.
That's the kind of light that
we see all the time.

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It let's us see the whole world
around us. But we're

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also pretty familiar with
another kind of light that
comes from the Sun.

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You know when mom makes you put
sunscreen on before you go
outside in the Sun?

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That's to help prevent damage
to you skin from an ultraviolet
light.

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We're also familiar with
infrared light.

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Infrared light is heat. That's
what we feel as heat,

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but it's actually a kind of
light. If you've ever been

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to the dentist or the doctor,
you might have had an x-ray
done.

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They are a kind of light that
can actually penetrate into

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your body and let a doctor see
inside what's going on with
your bones.

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So we have lots of different
kinds of light.

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Optical telescopes use visible
light. The same kind

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of light that our eyes can see
are what an optical telescope
can see.

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EVAN: Galileo used an optical
telescope, but the telescopes
today are much more powerful.

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In Hawaii, they have giant
mirrors that gather visible

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light from far away objects in
space.

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The light is too faint for us
to see with our naked eyes.

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But these giant telescopes make
dim objects like stars

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seem brighter and magnify the
images of distant planets,

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so we can look even farther
into space and see more clearly
than ever before!

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DR. HERBST: Another way to make
really big telescopes is

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to make more than one telescope
and link them together by
computer.

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So for example, on Mauna Kea is
the Gemini North telescope.

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Well, the Gemini South
telescope is located in Chile.

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So imagine having a telescope
that's mirror was so big,

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that it stretched from Hawaii
down to Chile.

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That would be a huge mirror and
we could never make a

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mirror that big on the Earth
and have it survive.

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But because of the way we can
link the telescopes together,

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those two observatories
separated by all those miles

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function as one telescope. And
the neat thing is when

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you're able to link them up
like that, now you've got the

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ability to almost see like our
eyes see. We have two

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eyes that see a little bit
differently don't they?

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You ever do the trick of
closing one eye and then
closing the other.

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And things look a little
different. Ok, that's called

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binocular vision. Well, having
two telescopes

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separated by a distance almost
gives us the same kind

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of effect with our telescopes.

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EVAN: Today's Earth-based
optical telescopes are getting
so powerful,

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that soon they'll be able to
see planets and stars as

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clear as the Hubble Space
telescope can.

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DR. HERBST: Telescopes. Optical
telescopes use a mirror.

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And mirrors have to be made in
a certain way in order for

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the images not to come out
fuzzy. Well, it's really

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hard to make really big mirrors
that don't give you fuzzy
pictures.

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So one way to do it is instead
of making one giant mirror,

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we make lots of small mirrors
and position them so they

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make one big mirror.

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Now each of those mirrors can
be controlled by a computer.

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So not only do you get the
advantage of a really big
mirror,

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but now let's say that the air
outside tonight when

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you're looking with your
telescope is a little foggy.

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You can actually control the
mirrors to focus the light to

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get rid of the fogginess from
the atmosphere.

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So that's one of the ways that
telescopes are now

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getting even better than back
in the days when we made
Hubble.

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EVAN: So Globey, today we've
learned that astronomers pay

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close attention to where they
build these giant
observatories.

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By building them on high
mountains, like the

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ones in Hawaii, they can avoid
many of the

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problems in the atmosphere that
make it difficult to look into
space.

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EVAN: So Globey, how do you
think Galileo would have looked
in a grass skirt?

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? [music] ?

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KIDS: Our World!