Researchers in Germany have announced new evidence of the world that collided with the earth billions of years ago to create the moon.

Analysis of moon rock brought back by Apollo mission astronauts shows remnants of the planet-like mass of space material researches have dubbed "Theia," which in Greek mythology was said to be the mother of the moon, as well as sun and dawn.

The researchers, from the University of Goettingen, claim that their discovery confirms the theory that emerged in the 1980s and explains the moon coalesced from then debris that resulted when the young Earth and Theia slammed into each other about 4.5 billion years ago.

Findings of the new research, published in the journal Science, indicate astronauts found material on the lunar surface that didn't appear to originate from the moon itself.

According to lead researcher Daniel Herwartz, his team was the first to find definitive evidence for the collision theory.

"We have now discovered small differences between the Earth and the Moon. This confirms the giant impact hypothesis," Herwartz told BBC News.

The impact theory, said Herwartz, has always offered a straightforward explanation for the moon's creation and fit well with computer simulations.

But, up until the latest discovery, evidence of Theia had never before been detected in lunar samples.

And there's still an unsolved piece of the puzzle, because, now that traces of Theia have been proved, it's not yet understood why the composition of Theia was so much more like that of Earth than the moon.

One possibility is that Theia was formed very close in proximity to the earth and, therefore, ended up being composed of the same elemental materials that the Blue Planet was.

An alternate and highly debated theory proposed by Prof Rob de Meijer of Groningen University in the Netherlands suggests the earth's crust and mantle were blasted into space by a buildup of nuclear material about 300 miles below the surface -- and the debris from that event drew together to that clumped together to form the moon.