CLAUS LUNAU/SCIENCE PHOTO LIBRARY
If an object hadn’t crashed into Earth to form the moon, as is hypothesised, Earth would be bigger. Would it still sustain life?
Ron Dippold
San Diego, California, US
You reference the giant impact hypothesis, the most favoured explanation for the moon’s existence and composition.
It suggests that, about 100 million years after our solar system started to form, proto-Earth got smacked by Theia, a Mars-sized planet. This knocked enough debris into orbit to form the moon. The early solar system was so crowded and chaotic, it was like the seven-lane “Magic Roundabout” in Swindon, UK, if all the drivers…
