Scientists may have been missing a crucial piece of the puzzle in explaining how the Moon came to exist, according to new research that revisits one of astronomy's most enduring questions.

The leading theory holds that early in the solar system's history, a Mars-sized object called Theia collided with Earth, and the debris from that impact eventually became the Moon.

But new simulations suggest that a factor long dismissed as irrelevant -- the temperature and physical strength of the colliding bodies -- may actually be central to how the event unfolded.

Researchers previously assumed that the extreme energy of the collision made the geological properties of the objects involved largely unimportant.

The new study challenges that assumption, reports The Independent.

Led by Adeene Denton of the Southwest Research Institute, the team ran simulations that factored in how the strength of rocky bodies changes with temperature -- hotter bodies being weaker, cooler ones more resistant.

The results varied dramatically depending on those conditions.

In some scenarios, the collision shattered Theia entirely, leaving behind a disc of debris that slowly coalesced into the Moon over time.

In others, using the same temperature parameters as earlier models, a fully formed Moon emerged within just five hours of impact.

"Depending on how hot the Earth and Theia are prior to the collision, the impact can destroy Theia and produce a massive disc of debris that eventually forms the Moon," Denton said.

"But when I used the same parameters as original impact modelling, within around five hours, an intact Moon emerged."

The findings could also shed light on one of the field's lingering mysteries: why the Earth and the Moon are so chemically similar.

One explanation is that Theia and Earth formed close together in the early solar system, while Mars developed further out.

"Because Earth and Mars formed in the same neighbourhood of the solar system, they are like siblings," Denton said. "The Moon and Earth are more like fraternal twins."

Robin Canup, who helped develop the giant impact theory in 2001, said the results could help scientists narrow down when exactly the Moon-forming collision occurred.

The study was published in the Astrophysical Journal Letters.