From 1969 through 1972, six Apollo missions landed on the moon and returned a total of

840 pounds of moon rocks to the Earth.

Geologists were able to study them and learned an enormous amount about the composition and

formation of the Moon.

However, those same rocks have been the center of several controversies and mysteries

ever since they came back.

Learn more about Moon Rocks and where they are now on this episode of the basics. What is a moon rock? A moon rock is a rock that comes from the moon.

Well that's pretty obviously a tautology. For the purpose of this episode I'm only going to focus on moon rocks which have been brought back to the Earth.

There aren't very many moon rocks on Earth. In fact, they're one of the rarest substances on the planet.

There are only four sources of moon rocks. The first source is meteorites that have landed on Earth that were ejected from the moon.

It's possible to tell the origin of meteorites by their chemical composition.

As of today, only 370 meteorite pieces have been identified as having come from the moon, and those only came from 30 sources.

None of them were found after an observed meteor falling from space.

The total mass of all the moon

meteorites found on Earth is around 190 kilograms or 420 pounds. The other

sources all come from human activity. The Chinese Changi-5 mission return 1.7 kilograms or 61 ounces of moon rock to the Earth in 2020.

The Soviet Union sent several unmanned probes to the moon during their Luna program.

Three of them managed to successfully return samples of Moon Rock back to the Earth.

Luna 16 and 1970 return 101 grams.

Luna 20 in 1972 return 55 grams. And Luna 20, 1972, return 55 grams, and Luna 24, 1976, sent back 170 grams of

Moon Rock. The total amount brought back by the Soviets was less than a third of a

kilogram. The largest amount of moon rock

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