WEBVTT FILE

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Reporter: Today is an exciting day and that's because
Mercury will transit across the face of the sun

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and here to tell us about this rare phenomenon is Dr. Alex
Young at NASA's Goddard Space Flight Center.

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Thanks so much for joining us.

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Alex: Thank you

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Reporter: So Mercury is trekking across the sun today for
the first time in ten years.

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How can we see this transit?

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Alex: If you're fortunate to have the right kind of solar
viewing

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equipment, telescope or binoculars with the appropriate
filters

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you can see it from the ground but the best way to see is
from space.

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We've got data coming from the Solar Dynamics Observatory

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which is going to show this roughly seven hour transit
uninterrupted.

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Reporter: Why are transits so important to astronomers?

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Alex: Well transits have been used for hundreds of years to
show

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us distances, like a ruler we can figure out how far away

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planets and the sun are.

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We've also be able to out sizes or even the fact that Venus has

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an atmosphere using transits.

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But transits are also important because they're how we

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figure out if there planets around other stars outside

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of our own solar system.

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Reporter: Why does NASA watch the sun?

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Alex: The sun is constantly putting out huge amounts of
energy

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and material, it's producing its own space weather

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that effects us here on Earth, effects our astronauts in
space

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and moves through out the entire solar system and

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this transit is import because it allows us to fine tune

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our observations of the sun to see even better detail

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by using the transit itself to fine tune and focus the
telescope

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to give us the best possible data to show us the sun

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in all its glorious detail.

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Reporter: So NASA is using the transit method to study
planets beyond our

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solar system, what do we expect to learn from future
missions doing this?

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Alex: We've already found thousands of planets around other
stars

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and we've got future missions like the

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Transiting Exoplanet Survey Sattelite or TESS

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which is going to look closest, brightest starts

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to give us a whole set of potential

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candidates that we can then point even more

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powerful telescopes like the James Webb space telescope

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at to see the atmosphere's of these stars

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look for the finger prints of life itself and hopefully get
a better

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understanding life on other planets and ultimately life on
our own planet.

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Reporter: Where can we learn more?

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Alex: You can go to www.nasa.gov/transit

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to see all this amazing imagery, videos,

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as well as learn more about transits

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or even special kinds of transits called eclipses

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and see something about the eclipse in August 21, 2017

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