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[silence, followed by music]

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[music] Narrator: As the moon orbits the Earth, it occasionally passes through the Earth's shadow, resulting

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in a spectacular change in the moon's appearance for a short time. This event is called a

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lunar eclipse, and it happens at least twice a year, providing a rare show that's worth staying awake

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for. But what would a lunar eclipse look like if you were on the moon? From that perspective,

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you would actually be viewing a solar eclipse, with the Earth blocking the Sun for a short period of

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time. The view would be spectacular, but there's more to it than that.

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Having such a large-scale "lights out" on the moon gives scientists a unique opportunity to study

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the moon's surface, and NASA's Lunar Reconnaissance Orbiter is in a position to do just

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that. So, what exactly does LRO plan to study? When the Sun is

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obscured, the moon cools down, but not every area cools at the same rate.

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Rough areas of the moon, with large rocks and boulders, cool down more slowly than areas with fewer

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large rocks. By measuring the temperature of the moon as it cools, scientists can identify

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which areas are rougher than areas. Earth-based telescopes have been doing something like this

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for years, but they're so far away that it's hard to get a good view. LRO's DIVINER

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instrument, on the other hand, can measure temperature at an extremely high resolution,

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giving scientists a first-ever up-close measurement of this kind. By taking these

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measurements, scientists can infer the size and density of moon rocks on a very small scale,

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teaching them new things about the moon's surface. And while they might not be able to get

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a view of the solar eclipse from the moon, they'll still get a look at the moon that's just as exciting.

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[beeping]