The Earth formed around 4.5 billion years ago from a cloud of dust and gas that collapsed under gravity to form a spinning disk. As the disk spun and separated into rings, the particles at the center became molten and formed the Sun, while the outer particles cooled to form planets like Earth. The Moon is believed to have formed from debris ejected during a giant impact between Earth and a Mars-sized planet called Theia. Without the stabilizing effect of the Moon, Earth's rotation would have been faster and its climate more extreme, potentially preventing the emergence of life.

1. By Luis Andrés Manchado
How was the Earth formed?
About one hundred billion years ago the Earth, the Sun, and
all the planets of the Solar System were nothing but a cloud of
cold dust particles swirling through empty space.
Gradually, these particles were attracted to each other and
came together to form a huge spinning disk.

2. As it spun, the disk separated
into rings and the motion
made the particles white-hot.
The center of the disk became
the sun, and the particles in
the outer rings turned into
large balls of gas and moltenliquid that cooled and
condensed to take on solid
form. Four or five billion years
ago, they turned into the
planets that we know today as
Earth, Mars, Venus, and the
outer planets.

3. Giant impact theory
The Giant Impact Theory says that Earth’s moon was created in an apocalyptic
collision between a planetary body the size of Mars called Theia and the early
Earth. According to the theory, the planet smashed up against Earth, releasing so
much energy that it melted and vaporized Theia and much of the proto-Earth’s
mantle. The Moon then condensed out of the cloud of rock vapor, some of which
also re-accreted to the Earth.
Without the
moon, planetary scientists
believe the Earth would
spin more rapidly, making
days shorter, weather
more violent, and climate
more chaotic, which they
believe would have also
resulted in humans not
coming to existence.

4. The Earth became a planet with a hard crust about
4000 million years ago. Even though it was a much
cooler place by then, it was still too hot to support
any forms of life. The Earth did not have any water
or air. Earthquakes, volcanic eruptions and
meteorites were common events at that time. The
eruption of volcanoes created our actual
atmosphere and oceans (the atmosphere has
prevented most of the meteorites to hit Earth ever
since). Meteors also hit the Moon, that’s why we
can see large craters when we look at it.