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Narrator: This is our inner solar system.
It consists of Mercury, Venus, Earth and Mars.
All of which travel around our sun.
Here you will also find the main asteroid belt
that covers a large, diffusely populated region of our solar system
roughly between the orbit of Mars and Jupiter.
It is here, in the main belt, where we find Themis -
a 200 to 250 kilometer wide asteroid,
which is about the distance from the northern border
of Tennessee to its southern border.
With the help of NASA's Infrared Telescope Facility,
UTK's Josh Emery found evidence for the first time
of water ice on the surface of an asteroid,
as well as evidence of organic material.
We have been monitoring asteroids in the main asteroid belt
for a number of years looking for specifically signatures of organic material
and not finding it. It's uncertain how widespread organics are in the solar system.
And the discovery of ice was just completely unexpected.
So finding ice at the position of the solar system we found it
and finding organic materials were both big discoveries in asteroid science.
Narrator: Emery's research data tells us that Themis' exterior
has a thin coating of ice, which is surprising since its surface
should be too warm for ice to remain for a significant length of time.
The researchers theorize that the asteroid's interior must have a rich
and uniform reservoir of water ice that slowly migrates to the surface
and replenishes the ice on the exterior.
The original nebula out of which the solar system formed - as it was forming -
had a lot of hydrogen, it had a lot of oxygen.
And so almost certainly it had a lot of water. The material from which the earth formed
was all close to the sun. The Earth was close to the sun.
And that material would have formed dry, but of course we have all this water
on the Earth. We couldn't live without all this water. So where did that water come from?
Well, now we are seeing that asteroids were probably very water-rich.
So it could have been perhaps the dominant carrier of water onto the Earth.
Narrator: For Emery, space is more than the dark void that envelopes our lonely planet.
For him, space is a vibrant place of discovery and exploration,
holding mysteries waiting to be explained.
When I go to the telescope and I point it at Themis, and I collect data,
no one else has seen that data before. There was a time when I was the only
one in the world who knew there was water ice on Themis.
That's a really cool feeling.
Exploration, I think, is thrilling to me and that growth of thought
that it produces I think that humankind just needs.
It's like, why study art?
Because art makes us think in new ways. It expands our horizons
in ways we didn't plan. And exploration, the study of space, the study of new things
does that as well.