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[silence]

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[music]

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sterile, gray, unchanging world. But while the moon has

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remained largely unchanged during human history, our own understanding of it has

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evolved dramatically. Thanks to new observations,

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we now have not only unprecedented views of its surface, but a whole

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new tour of the moon that shows how both it and other rocky planets in our solar

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system have been shaped over billions of years.

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We'll start with one of the largest impacts--Orientale Basin, a feature

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that's as wide as the distance from New York City to Cincinnati. Using new

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elevation measurements, we can clearly see the effects of what is likely the last

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giant impact event in lunar history, with its outer mountain rings

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rising many kilometers above the lowest points inside the crater.

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The interiors of some craters in the moon's polar regions, like Shackleton,

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haven't seen sunlight in over two billion years. However, new

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measurements have created our best-yet maps of these types of craters, allowing us to

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see deep into the shadows of this surprisingly young-looking impact crater

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in the south that's more than twice as deep as the Grand Canyon.

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Some impacts are invisible for other reasons. Although the ancient South Pole-Aitken Basin

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is difficult to see from orbit because it is so large,

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new LRO topography maps reveal the largest impact basin in the Earth-

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moon system, measuring several kilometers in depth and around 2500

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kilometers in diameter. Only the Hellas basin on Mars

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rivals it in size. One of the youngest

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large-scale impacts on the moon is the Tycho Crater. This fresh crater

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may have formed only 108 million years ago--when dinosaurs roamed the Earth.

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We now also have an extreme close-up view of the crater's

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central peak--revealing a mountain with sharp edges, building-sized

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rocks, and a central boulder about the size of a baseball stadium.

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[music]

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Narrator: The Aristarchus Plateau is another recent lunar formation that has

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long interested scientists and astronomers. The crater itself

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formed in the same era as the Tycho Crater, and what appear to be snaking river valleys

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were actually carved by ancient lava flows.

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[music]

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Narrator: Next, we arrive at Mare Serenitatis on the near side of the moon. In December

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of 1972, the crew of Apollo 17 landed in the Taurus Littrow

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valley, marking the last time humans have visited the surface of the

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moon. With images from LRO's narrow-angle

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camera, we can clearly see the evidence of that visit. In this

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image, you can easily see the base of the lunar lander, along with the lunar

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rover, parked far from the blast-off zone. You can also

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clearly see the astronaut trails and the wheeltracks left on the lunar surface.

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[music]

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Narrator: We now head to the far side of the moon--which cannot be seen from Earth. Our

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first stop is the Compton-Belkovich region, which shows evidence for young volcanic

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activity in the farside highlands. This feature is unique

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not only because it is isolated from other volcanoes in the area, but also

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because it is located nowhere near the maria, where volcanoes are usually found.

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Also, on the far side, we find

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the Jackson Crater--which like the Tycho Crater on the near side, has an

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extensive and complex ray system. In fact, this crater is often considered

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to be like a twin to Tycho. Finally, the

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Tsiolkovsky Crater stands out as an excellent example of a farside crater

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filled with a sea of ancient lava--known as a mare. It is

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particularly interesting to scientists and other observers because of its isolation

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from other similar craters--as well as its beautiful central peak.

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As we continue to study the moon, our understanding of it

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improves, giving us new insights not only into how it has evolved over

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time, but also how other rocky planets in our solar system have come to

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look the way they do. With new missions, new instruments,

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and new technologies, we will continue to improve our knowledge of the moon...

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...and better understand the history of our solar system.

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[music fades]

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[beeping]

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[beeping, silence]