Untitled Page

Today scientists say that 3.5 billion years ago, when our solar system was nothing like it is today, a planet the size of Mars crashed into another planet, forming the foundation for the Earth as we see it today.

Not only did this alien planet fuse with our planet, and give birth to a new world, but a massive piece of this cosmic collision is thought to have ended up in space, eventually forming what we know today as the Moon.

This story is part of the giant-impact hypothesis where a planet called Theia crashed into Earth. The giant impact hypothesis has been the preferred explanation in the scientific world of how the planet we live on today came to be, and how we have a massive moon orbiting our world.

Although this theory is mostly accepted in the scientific world, evidence of such a collision was nearly nonexistent until now. According to a recently published paper, we’ve just found traces of a chunk of Theia, buried deep inside the moon.

Planetary scientists decided to reanalyze lunar samples. Their study revealed something fascinating: the levels of oxygen isotopes that they analyzed in some of the moon samples were found to vary depending on the lunar rocks they tested. The deeper the rock samples of the moon, the heavier the oxygen isotopes were compared to those from Earth

This suggests that although the outer parts of the Moon were pulverized during the heavy impact, they have similar characteristics to that of Earth. Deep within Earth’s natural satellite are traces of Theia that remain largely intact. Theia’s distinct oxygen isotope composition was not completely lost through homogenization during the giant impact,” the researchers explained in their study.

We know very little about Theia, but the paper published in Nature Geoscience suggests that the world that gave rise to the moon probably formed farther out in the solar system, and made its way towards the inner planets, eventually crashing into the early Earth.