WEBVTT FILE

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So X-rays
really show us that the universe

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is very energetic.

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We find X-rays in jets

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erupting from the centers
of active galaxies.

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We use them to measure the spin
of black holes

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or supernova explosions.

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It takes a powerful event

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to produce cosmic X-rays.

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Sometimes people also call it
the hot universe

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because, you know, when you have this gas

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in galaxy clusters or also around galaxies
that you can see only in X-rays.

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This gas is about 10 million
to 100 million degrees,

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which is so hot that this gas does not
radiate in the

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optical, does not radiate in the infrared,
but only radiates in X-rays.

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To understand these hottest regions.

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We need the next-generation X-ray

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telescope.

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The Japan Aerospace Exploration Agency,
or JAXA, is partnering with NASA

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and the European Space Agency to launch
the next-generation

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X-ray Space Telescope.

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The telescope,

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called XRISM, launches
from the Tanegashima Space Center

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at the southern end of Japan on an H-IIA

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rocket.

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The spacecraft weighs over 5,000

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pounds, stands over 30 feet tall
and will orbit

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approximately 340 miles above Earth.

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We're familiar
with the medical uses of X-rays.

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X-ray light is energetic enough
to pass through our skin.

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Our calcium dense bones absorb that light,

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blocking it from reaching the detector
and creating a shadow.

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Luckily for us, X-rays

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from space
don't make it through our atmosphere.

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But what that does mean
is that we have to send X-ray

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hunting missions into orbit
to detect this high-energy

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light.

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XRISM also needs special kinds of mirrors,

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which are built at NASA's
Goddard Space Flight Center.

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The type of the mirror
is called nested mirror

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that looks like
a cross-section of an onion.

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X-rays are

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so energetic, they fly right through
typical mirrors

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For the visible light,

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we typically place them like this,
so that light just bounces back.

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But for the X-rays, this doesn't work

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so that we put the mirror like this,

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so that X-rays just grazes
the surface of the shell.

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When they strike mirrors at very shallow
angles,

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X-rays, too, can bounce.

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And then so
we made it like a conical shell,

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like this.

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Then X-ray can be directed.

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XRISM

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has two instruments, each
with their own mirror assembly,

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one for imaging, called
Xtend, the other for spectroscopy,

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called Resolve.

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JAXA built Xtend to provide XRISM
with a wide

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field of view.
It can observe an area about 60% larger

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than the average appearance
size of the full moon.

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NASA's Resolve instrument

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is a spectrometer
that splits X-ray light like a prism

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so scientists can detect specific

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elements present in the sources
they're studying.

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It uses a small six-by-six

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pixel detector called a microcalorimeter,
nestled

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in a refrigerator-sized container of liquid helium.

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Resolve
will measure the small temperature changes

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caused
when X-rays hit one of those pixels.

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To track such
small temperature changes, Resolve’s

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detectors must be kept extremely cold.

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That liquid helium
cryocooler will keep the instrument

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at 0.05 degrees.

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It's so cold

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it is a fraction of a degree above

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absolute zero.

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Heat is simply a product of moving atoms

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keeping Resolve’s detector that cold means
that the atoms barely move.

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So there's very little thermal noise
in the system.

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It's what keeps these
accurate measurements

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possible.

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Each X-ray detected will help scientists
pursue

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many questions
about the hottest regions of the cosmos.

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What's happening

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in the extreme
gravitational fields around black

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holes?

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Can we discover

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what is inside a neutron star?

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How did some of the universe's
largest structures

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like galaxy clusters, evolve?

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Optical Telescope,

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you will just see galaxies everywhere.

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If you if you look at this
same cluster of galaxies in X-rays,

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you will see actually a lot of gas.

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And this gas constitutes
actually most of the matter

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the cluster of the galaxies,
which is something it's important

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to to understand,
because it means that most of the matter

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in the universe
is not in the form of planets or stars,

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but it's really in the form of this
all of this gas. So.

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But XRISM really has this capability
of decomposing this X-ray light

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in a way that's much, much more accurate
than what has

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ever been done before.