SCIENCE LAB SCIENCE : ORIGIN STORY

IN a ' vast cosmic billiard game,' Earth got its moon from a carom shot. Not long after Earth formed, it received a big sucker punch when an object roughly the size of Mars slammed right into it.

The interloper known as Theia, was destroyed and part of it and Earth sprayed into space. The result was the moon.

It's a violent, elegant theory for how Earth got its moon. But questions about this moon-making cataclysm remain. One unanswered  query : Where in the solar system did Theia come from?

A study in the journal Science may shed light on the question. By looking at chemical clues hidden in Earth's rocks, meteorites and moon matter, scientists have found ghostly remnants of Theia.

And they show that Theia and the early Earth were built from the same construction materials.

That explains why the chemistry of moon rocks is so similar to Earth's : Theia's impact on a chemically similar Earth would make a moon that resembled both orbs.

This also means that Earth and Theia took shape in the same part of space, in a swirl of dust and gas next to an adolescent sun, in what we now call the inner solar system.

Although there are several hypothesis as to how Earth got its Moon. Theia is the prime suspect.

The proposed object explains much about the Earth-moon system, and the solar system's  planet-making era '' resembles a vast cosmic billiard game, said Nicolas Dauphas, a cosmochemist in Hong Kong and an author off the new study."

Back then, big impacts were common. Eventually, these dropped off, but didn't disappear entirely.

'' Earth happened to have been hit by a late one,'' said Thorsten Kleine, a geochemist in Germany and an author of the new study.

This Universe Creation and Research publishing continues. The World Students Society thanks Robin George Andrews.