What do Moon rocks reveal about the universe? | The Economist

Between 1969 and 1972 six Apollo missions returned to Earth with Moon rocks. It was hoped that they would unlock lunar secrets but they also ended up teaching scientists more about the creation of the Earth and the universe beyond.

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These have been described as the most expensive rocks in the world. Until NASA’s Apollo moon missions they’d laid on the lunar surface for millions of years undisturbed by humans.

From 1969 to 1972 there were six Apollo missions which returned to Earth with samples. It was hoped they’d uncover secrets about the Moon – they ended up teaching scientists a lot about the Earth too.

Nine containers of lunar samples were brought back to Earth. Scientists studying the rocks learnt a great deal about the many impacts early in the Moon’s development. These created huge craters – some the size of large countries.

Ancient volcanic eruptions then filled some of these basins with vast plains of lava, creating the dry seas that can be seen by humans on Earth billions of years later.

But the moon rocks also revealed the biggest impact was the one that created the Moon itself. Scientists found the Moon rocks to be surprisingly, perhaps disappointingly, like those on Earth. It turns out that the Earth and the Moon are chemically very similar indeed, as if twins.

It was this revelation that led to a game-changing idea – The giant impact theory. The latest version of this theory involves the new idea of a synestia. In this theory the impact fills nearby space with a doughnut of hot vapour. Both the Moon and Earth are formed from the magma rain that resulted. The gravitational pull which binds the Moon and Earth to each other became the main cause of the rise and fall of the Earth’s ocean tides.

Scientists believe these tides could have been crucial for the evolution of animal life on Earth by offering a route from under the sea to above it.

For almost 50 years no human has returned to the Moon. Now missions are being planned to its unexplored territories. The hope of the next generation of scientists is that by studying new samples of rock they can unlock many more of the Moon’s secrets – and even some of the Earth’s.

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