Why do we say that the Moon is younger than the Earth?

Human beings have always wondered about the origin of the Moon. The Greeks were perhaps the first to study our satellite. But, modern scientific study of our natural satellite moon began in 1609, and there are many theories about its origin. The most popular one is ‘Giant Impact Hypothesis’.

According to this theory, about 4.5 billion years ago, our Earth was hit by a large body which was about the size of Mars. This impact blasted portions of the Earth into the Earth’s orbit. The broken pieces gradually came together, along with the gas and dust which solidified, to form the Moon.

Molten lava then oozed out of the interior of the Moon for the next two billions of years old, it is still younger than the Earth.

moon earth

image source: wikimedia commons