Our Planet, the Earth

Around 170 million years after the formation of the Earth, another young planet known as Theia struck the Earth’s still soft crust. Theia was demolished after the collision, and it merged with the Earth. The Earth’s mass therefore increased, effectively reaching its current mass. The impact created a large ring of debris around the Earth, which later formed into the Moon. After the dissolution of the ring, the Moon became a glowing hot celestial body orbiting 25,000 kilometres above the Earth. During this period, the Moon still had volcanoes, lava flows and its own magnetic field.

Impact crater

The surface of the Moon is peppered with craters, most of them caused by meteorite impacts. Many of these are covered with solidified lava, which used to be mistaken for seas. Some younger meteorite craters can also be found on Earth.

1. Impact

Around 4.5 billion years ago, another young planet known as Theia struck the Earth’s still soft crust.

2. Debris cloud

A ring of debris formed around it after
the collision.

3. Solidified Moon

After the dissolution of the ring, the Moon became a glowing hot celestial body.

Barringer Crater

Location: Northern Arizona, US

Age: about 50 000 years

Diameter: 1.2 km

Spider crater

Location: Kimberley Region, Australia

Age: approx. 600–900 million years

Diameter: 13 km

Lonar crater

Location: Maharashtra, India

Age: approx. 50 000 years

Diameter: 1.8 km

Manicouagan Reservoir

Location: Quebec, Canada

Age: approx. 210 million years

Diameter: 100 km