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? [music] ?

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KIDS: Our World!

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EVAN: Today on Our World we’re
going to learn about...

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Globey, what are you wearing?

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X-ray glasses? You know those
things don’t actually work,
right?

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I know, I know, I’d like to
have X-ray vision, too.

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But there is a space telescope
that actually DOES

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have X-ray vision...the Chandra
X-Ray Observatory.

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This state-of-the-art space
telescope observes X-rays to

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help us learn new things about
our universe.

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So what is an X-ray? It’s a
type of light that has a really
short wavelength.

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Visible light, or the light we
can see, has a wavelength that
looks like this.

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X-ray wavelengths are much
shorter.

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This short wave length allows
the x-ray to pass through many
objects.

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That’s why doctors use X-rays
to look at broken bones.

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X-rays pass through our skin.

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The x-rays, however, are
stopped by the bone.

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X-ray film can be used to
detect the x-rays and the

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shadow of the things the x-rays
cannot pass through.

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When you go to the dentist,
X-ray pictures are taken so

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the dentist can see what’s
happening INSIDE your teeth.

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X-ray telescopes can be used in
a similar way to look at

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shadows caused by clouds of
dust and gas in space,

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but usually they are used to
look at "x-ray machines"

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in the universe such as hot gas
produced by the explosion of a
star,

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to see a kind of light that 
isn’t visible with a regular
camera.

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The Chandra X-ray Observatory
is named after a 
astrophysicist,

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Subrahmanyan Chandrasekhar, or
Chandra for short.

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Chandra made new discoveries on
how and why stars change.

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He was one of the first
scientists to combine physics

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(the study of matter and how it
moves) with astronomy

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(the study of objects in the
universe). He was awarded the

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Nobel prize for his study of
stars.

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The Chandra X-ray Observatory
was launched in 1999.

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It allows NASA scientists to
get a whole new view of the
universe,

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kind of like looking out into
space with a pair of "X-ray
glasses".

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Stars and other matter in space
give off X-rays under

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certain violent conditions.
Scientists can now observe

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what it looks like when
galaxies collide or supernovas
explode.

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Seeing these hot spots in the
universe gives scientists

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information they could never
get from taking regular
pictures.

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So why can the Chandra X-ray
telescope capture such
brilliant images?

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Chandra is the best X-ray
imaging telescope ever built.

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Its power is like being able to
read a stop sign at a distance
of 19 kilometers.

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But this special telescope
wouldn’t work here on Earth.

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It had to be placed high in
outer space.  You see,

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Earth’s atmosphere is thick
enough that X-rays are not

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able to reach Earth’s surface. 
Chandra’s orbit

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around Earth is so big that the
farthest points of the

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oval shaped orbit are about one
third the way to the moon.

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Even at is closest approach to
Earth, Chandra’s orbit is more
than

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200 times higher than the
circular orbit of Hubble.

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This gives the Chandra
telescope an ability to look

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for X-rays that are being
produced by faraway objects in
space

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in a large region of the sky
without the Earth blocking its
view.

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With the help of special
mirrors and a high-resolution
camera,

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Chandra is able to "see" x-rays
in action!

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Whoa! That’s some incredible
X-ray vision, huh Globey?

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Chandra’s observations have led
to important discoveries

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that are accumulating at a
rapid rate as Chandra

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observes hundreds of objects
each year.

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Observations of the collision
of two huge clusters of

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galaxies has helped to provide
the best evidence yet

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for the existence of dark
matter, a mysterious form of

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matter that gives off no
detectable light, but is

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apparently the dominant form of
matter in the universe.

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Chandra has also been used to
probe the geometry of space
around black holes,

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and revealed that  
supermassive black holes can
affect an entire galaxy.

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If Chandra was still alive
today, I’m sure he’d be

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thrilled to see all the amazing
information the X-ray telescope
is providing us.

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So the next time you’re at the
dentist getting teeth X-rays,

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think about the Chandra X-ray
Observatory...giving us an

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inside look at the “X-ray
machines” of the universe!

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? [music] ?

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KIDS: Our World!