In a recent study, scientists from the California Institute of Technology looked into a mystery about how the Moon was formed. They think they may have found evidence that an ancient planet called Theia is connected to the Moon's creation.

According to the most popular idea, the Moon was created when a planet called Theia crashed into Earth a very long time ago.

This collision caused a lot of debris, and from that debris, the Moon was formed. But until now, there was no concrete proof of Theia's existence.

Now, these scientists have found some big, iron-rich things deep inside Earth. They believe these might be the last parts of Theia hidden deep inside our planet.

If this turns out to be true, it's a huge deal because it could change how we understand Earth's history and how the Moon was born.

Main theory

The main idea here is something called the "giant impact hypothesis".

It says that Theia used to go around the Sun, pretty close to Earth's path. But because of the pull from other big planets like Jupiter and Venus, Theia got pulled away from its path and eventually crashed into Earth.

That's how the Moon came to be.

Findings

To support this idea, scientists looked at rocks brought back from the Moon by astronauts during the Apollo missions.

These rocks are a lot like the outer layer of Earth which made people think the giant impact theory was true.

But, they still didn't have direct proof that Theia existed, until now.

Significance of new discovery

The key to this new discovery is large low-velocity provinces (LLVPs) which are like huge blobs deep within Earth.

Scientists have known about them since the 1980s, but their origin was a mystery.

These LLVPs are special because they have a lot of iron in them. They make seismic waves (the kind of waves created during an earthquake) slow down when they pass through. It's like they're different from the rest of Earth's insides.

During a seminar about planet formation, one of the scientists had a realization.

Dr Qian Yuan thought that Theia which had a bunch of iron might have turned into these LLVPs deep within Earth.

So, the scientists used smart computer simulations to see what would happen if Theia smashed into Earth.

These simulations showed that this kind of crash would make the LLVPs in Earth's insides and create the Moon.

The result of all this is that instead of mixing evenly with Earth's insides, the pieces of Theia formed two separate groups, sort of like how wax in a lava lamp moves.

Because of cooler conditions deep inside Earth, these groups of stuff stayed mostly whole and went down closer to the centre of our planet.