NASA provided a unique view of the moon from the side that can't be seen from the Earth and explained how the images were captured. (YouTube/NASA)

Thanks to NASA, we now know what the solar system looks like, centered on a view of the moon's far side. The computer-generated time-lapse gives two views of the lunar cycle from the side of the moon we never see from Earth.

Although it doesn't appear to spin from Earth's perspective, the moon does rotate, once about every 27 days. That's also approximately the same amount of time it takes the moon to orbit the Earth, once. The phenomenon is called synchronous rotation. In all, about 59 percent of the moon is visible from Earth over the course of an orbit. We never ever see 41 percent of the moon - the side that many call "dark."

But the "dark" side of the moon has always, from its perspective, gotten plenty of light. When Earth sees a waning crescent, the far side is nearing fullness.

And it's light in another sense, too: The "dark" side has few of the distinctive dark spots that mark the Earth-facing side of the moon. Those spots are called maria, from the Latin word for sea, because early astronomers mistakenly thought they were lunar seas (they're actually volcanic plains). The smooth and dark maria cover 17 percent of the surface of the moon. Almost all of them are visible from Earth.

Humans first got a look at the far side of the moon in 1959, thanks to the Soviet Union's Luna 3 spacecraft. The images were grainy, but still showed a surface very different from what the moon showed Earth:


NASA now has tens of thousands of images of the moon all the way around, which can be used to make much more detailed projections, like this one:

(NASA/GSFC/Arizona State University)

The mystery of the "dark" side's lighter surface has long been a difficult question for scientists. Although the going theory has been that the maria were the result of a huge asteroid impact, recent research suggests that the dark surface of the Earth-side moon is the result of ancient magma flooding.


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