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This is a group

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of galaxies known as Stephan's Quintet.

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Quintet meaning five, of course.

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And you can see them here.

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One, two, three, four, five.

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Although, it's really just a visual
quintet because it turns out that

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the galaxy here on the left
is a lot closer than the other four.

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The other four are at a distance
of about 290 million light years away.

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And the nearby one
is only about 40 million light years away.

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You can also see its difference
in color and details.

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They're still all in our deep universe.

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And they make
for a very interesting picture.

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The ones on the right

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are actually gravitationally interacting
with each other.

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They are feeling each other's pull,

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and that's creating structural changes
in these galaxies.

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You can even see evidence that the spiral
structure in these galaxies is becoming

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distorted as they feel each other's
gravitational tug.

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It's creating long tails of stars
and star formation between the galaxies.

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Because as you have more regions
where gas is stirred up and compacted,

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that's the recipe
for more clumps of gas in

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each of these galaxies
to collapse and form more stars.

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You can see these two are closer
in this dance of merging.

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And all of this is evidence
of the merging process of galaxies

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that we now know is very common
in the history of our universe.

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Galaxies that are close enough
to each other will feel each other's

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gravitational pull.

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They'll come toward each other.

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that creates a little dance
as they orbit around each other, sometimes

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go through each other
and they distort each other structure.

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So you can see this cosmic dance
going on right now

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in Stephan's Quintet, and you can see
some of the impacts of that.

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So we

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can see that
the galaxies are connected to each other.

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Now and they're showing us
that merging is an important part

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of forming structure
in stars and galaxies.

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We actually believe

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that most galaxies have gone through
at least one merger in cosmic history.

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We believe our Milky Way
has and will again.

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So we want to watch this dramatic dance
so that we understand how galaxies

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have formed and grown over cosmic history,
including our own Milky Way.