Simplify the following text for a Grade 10 native English-speaking person.
Original: This has led to the giant impact hypothesis , the idea that the Moon was formed during a giant impact of the proto-Earth with another protoplanet by accretion of the material blown off the mantles of the proto-Earth and impactor .
Simplified: This has led to the giant impact hypothesis : the idea that the Moon was formed during a giant impact of the proto-Earth with another protoplanet .