~4.5 billion years agoReputable sourceWell documented
Earth and the Moon
On the timeline · around ~4.5 billion years ago · The Solar System & Us
What happened
The young Earth finished forming about 4.5 billion years ago. Around the same time, according to the leading theory, a Mars-sized body — nicknamed Theia — collided with the Earth, flinging molten and vaporized rock into orbit. That debris quickly gathered together to form the Moon.
Why it matters
The giant impact gave Earth its large Moon, which stabilizes the planet's tilt and drives the tides — conditions that helped make the Earth hospitable to life.
Sources
- NASA Science. Moon Formation · Reputable source