The Giant Impact Hypothesis, also known as the Theia Impact or the Big Splash, is a theory which suggests that the moon formed after a huge rock hit our planet. According to scientists, the object that hit Earth was Mars-sized. The huge rock was named Theia. The debris caused by the collision is the one that led to the “creation of the moon.
This theory is a popular one. However, it has been challenged recently by computer models. Calculations revealed that material from Theia should make up more than 60 percent of the moon if The Giant Impact Hypothesis was true. But, it appears that scientists did not find any chemical fingerprints of Theia on the Moon. Lunar rocks have mostly material from our planet.
Natsuki Hosono from Japan’s Agency for Marine-Earth Science and Technology posted a new theory in the Nature Geoscience which explains why there are no Theia traces on the Moon. According to the paper, our planet was still young and covered with a magma ocean at the moment of the collision.
The Moon formed from the Earth’s magma, according to the Giant Impact Hypothesis
“We perform density-independent smoothed particle hydrodynamic collision simulations with an equation of state appropriate for molten silicates. These calculations demonstrate that, because of the large difference in shock heating between silicate melts and solids (rocks), a substantial fraction of the ejected, Moon-forming material is derived from the magma ocean, even in a highly oblique collision,” explained researchers.
If our planet was covered in molten this would explain why more of Earth’s material was ejected into space. The new theory matches the mass of the moon as well.
“We show that this model reconciles the compositional similarities and differences between the Moon and Earth while satisfying the angular momentum constraint,” added researchers.