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KIDS: Our World!
EVAN: Hey Globey, have you ever done the hula?
Why am I wearing a grass skirt?
Because today we're going to Hawaii!
Well, we're not really, but we are going to talk about
some cool observatories in Hawaii. Do you know what an observatory is?
That's right! Telescopes are instruments that help make
distant objects look larger and nearer.
And observatories are where astronomers use telescopes to look out into space.
There are two basic types of observatories.
One is earth-based, which means the observatory is located here on Earth.
The other is space-based, which means the observatory
is in outer space, such as the Hubble Space Telescope.
Hubble is one of the giant telescopes that orbits Earth
and sends back amazing pictures of our universe.
You can find Earth-based observatories all over the
globe, but today we're going to talk about some special
earth-based observatories in Hawaii.
Hawaii is our 50th state, and it's made up of hundreds of
small islands in the Pacific Ocean.
Some of the observatories here are built on the Big
Island of Hawaii on top of the Mauna Kea summit.
Mauna Kea is a Hawaiian name that means the "white mountain."
But it's not just any kind of mountain. It's a dormant volcano crater.
Dormant means the volcano is not going to erupt anymore.
High on this mountain, astronomers from several
different countries operate 13 of the world's most
powerful Earth-based telescopes of different kinds.
Observers on Earth have to look into space through Earth's atmosphere.
As light travels through the atmosphere, it bounces off
particles in the air and may appear fuzzy.
Clouds and city lights interfere with the view as
well, making faraway light hard to see.
So astronomers built these big observatories on Mauna
Kea to advantage of the high altitudes.
The summit, or very top of the volcano, is so high up
that it's actually free from most of the pollution in the sky.
The air here is thinner or less dense, so there are
fewer particles to scatter the light.
Also, there is less water vapor in the air here so
there are almost never any clouds covering the summit.
Astronomers usually have a clear sky to look into outer space.
And because the telescopes are on an island, there is
less light pollution, so astronomers look out into an
extremely dark sky to observe some of the faintest far off galaxies.
Some of the observatories in Hawaii use optical
telescopes, which means they see in "visual" light.
DR. KELLY HERBST: Well light comes in many different varieties.
We know about visible light. That's the kind of light that we see all the time.
It let's us see the whole world around us. But we're
also pretty familiar with another kind of light that comes from the Sun.
You know when mom makes you put sunscreen on before you go outside in the Sun?
That's to help prevent damage to you skin from an ultraviolet light.
We're also familiar with infrared light.
Infrared light is heat. That's what we feel as heat,
but it's actually a kind of light. If you've ever been
to the dentist or the doctor, you might have had an x-ray done.
They are a kind of light that can actually penetrate into
your body and let a doctor see inside what's going on with your bones.
So we have lots of different kinds of light.
Optical telescopes use visible light. The same kind
of light that our eyes can see are what an optical telescope can see.
EVAN: Galileo used an optical telescope, but the telescopes today are much more powerful.
In Hawaii, they have giant mirrors that gather visible
light from far away objects in space.
The light is too faint for us to see with our naked eyes.
But these giant telescopes make dim objects like stars
seem brighter and magnify the images of distant planets,
so we can look even farther into space and see more clearly than ever before!
DR. HERBST: Another way to make really big telescopes is
to make more than one telescope and link them together by computer.
So for example, on Mauna Kea is the Gemini North telescope.
Well, the Gemini South telescope is located in Chile.
So imagine having a telescope that's mirror was so big,
that it stretched from Hawaii down to Chile.
That would be a huge mirror and we could never make a
mirror that big on the Earth and have it survive.
But because of the way we can link the telescopes together,
those two observatories separated by all those miles
function as one telescope. And the neat thing is when
you're able to link them up like that, now you've got the
ability to almost see like our eyes see. We have two
eyes that see a little bit differently don't they?
You ever do the trick of closing one eye and then closing the other.
And things look a little different. Ok, that's called
binocular vision. Well, having two telescopes
separated by a distance almost gives us the same kind
of effect with our telescopes.
EVAN: Today's Earth-based optical telescopes are getting so powerful,
that soon they'll be able to see planets and stars as
clear as the Hubble Space telescope can.
DR. HERBST: Telescopes. Optical telescopes use a mirror.
And mirrors have to be made in a certain way in order for
the images not to come out fuzzy. Well, it's really
hard to make really big mirrors that don't give you fuzzy pictures.
So one way to do it is instead of making one giant mirror,
we make lots of small mirrors and position them so they
make one big mirror.
Now each of those mirrors can be controlled by a computer.
So not only do you get the advantage of a really big mirror,
but now let's say that the air outside tonight when
you're looking with your telescope is a little foggy.
You can actually control the mirrors to focus the light to
get rid of the fogginess from the atmosphere.
So that's one of the ways that telescopes are now
getting even better than back in the days when we made Hubble.
EVAN: So Globey, today we've learned that astronomers pay
close attention to where they build these giant observatories.
By building them on high mountains, like the
ones in Hawaii, they can avoid many of the
problems in the atmosphere that make it difficult to look into space.
EVAN: So Globey, how do you think Galileo would have looked in a grass skirt?
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KIDS: Our World!