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Exozodiacal dust.

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If we break this word
down, exo means external.

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And zodiacal, similar to the word zodiac,

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means the portion of the sky through
which the Sun and the planets move.

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Put these two compounds together
and you get exozodiacal dust.

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But what does this mean?

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Exozodiacal dust is the dust around stars

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produced mainly by colliding asteroids
or passing comets.

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We can see these same tiny grains
in our solar system, too.

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The dust reflects sunlight,

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so we can often see it in pictures
taken at dawn or dusk.

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This is an illustration
of exozodiacal dust.

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So why look at exozodiacal dust,
the dust outside of our solar system?

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Distribution patterns of space dust
can offer clues about planets

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orbiting other stars,
and the amount of dust in a star system

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can inform scientists
about the frequency of comet activity.

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NASA's Roman telescope,
launching in the next few years,

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will study the chemistry of exozodiacal
dust to better understand how

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rocky planets form.