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This is an ultraviolet image of the planet Saturn.

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Saturn looks a little different
in the ultraviolet.

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You can still see the edges of the rings
here.

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But the reason we use the ultraviolet
with the Hubble Space Telescope

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is because of what you see in the poles
here.

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Those are the aurorae of Saturn.

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They glow really beautifully
in the ultraviolet.

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So the Hubble Space Telescope
is one of the key tools

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that we have had to study these beautiful

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aurorae of Saturn.

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This is a sequence of ultraviolet images

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with the Hubble Space Telescope, and
what you can see is how dynamic they are.

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They don't just sit there glowing.

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The glowing part is changing all the time.

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And it's changing
because our sun is changing

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and our sun is spewing out
particles all the time.

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And when these particles hit this planet,
they get sucked into the magnetic field

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and then they get deposited
at higher altitudes.

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So what you're seeing here is really
a combination of Saturn changing, but also

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our sun.

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What’s particularly special about this
Hubble image is

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it was taken at a time close
to what we call the ring-plane crossing.

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So the rings are almost in a straight line
relative to us.

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They almost disappear.

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Saturn takes 30 years
to make a trip around the sun.

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So the Saturn year is 30 Earth years long.

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We only get this particular orientation
twice in that 30 year orbit.

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So every 15 years we have an opportunity

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to see this sideways view of Saturn.

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Most of the time Saturn is tilted

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one way or the other
relative to the sun and to us.

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And what's great about that
is that it allows us to see

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both the northern and the southern pole
together at the same time.

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By using
the Hubble ultraviolet observations

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we can see the aurorae.

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That's the first thing.

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And we can actually see variations

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in the aurorae around
what we call the auroral oval.

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And that allows us to track out
the strength of the magnetic field,

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depending on how bright these aurorae are.

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One of the things you can tell from
an image like this from Hubble

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is that the aurorae in the north and south
are pretty comparable in brightness.

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And that means that the magnetic field
strength here

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is pretty similar in these two poles.