New research may explain why the moon contains elements similar to Earth, a question that has plagued scientists studying how the moon was born.

The long-standing "Giant Impact Theory" posits that the moon was created when a newborn Earth collided with a Mars-sized rock called Theia billions of years ago. The predominant theory is that debris from Theia shot into the atmosphere after the collision and coalesced to form the moon, according to several science publications including Space.com and Astronomy Magazine.

But scientists haven't quite been able to explain why the elements found in moon rocks and Earth rocks are so similar. The new study, published Monday in the journal Nature, has a potential explanation: If Earth was made of molten magma at the time of the collision, more of its elements could have been launched into space with the debris, according to a report by Space.com.

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The study was done using advanced computer models that simulated an Earth covered in an ocean of magma, which is consistent with most models of the planet's formation, the report said.

They results suggest that if Earth were molten at the time of the Theia collision, instead of solid, then much more Earth material could have been blasted into space, leaving the Moon mostly made out of our planet instead of Theia.

"Prior work on lunar formation basically ignored the effect of the magma ocean," lead author Natsuki Hosono, from Japan’s Agency for Marine-Earth Science and Technology, told Space.com. "Our research concluded that the magma ocean is one of the most important things for the moon-forming giant impact."