How Are Planets Formed?

What are the types of planets in our solar system?

Our solar system has eight planets. The first four are Mercury, Venus, Earth, and Mars. They're called terrestrial planets because they have solid surfaces and cores. These are the inner planets.

The other four are Jupiter, Saturn, Uranus, and Neptune. They're known as Jovian planets or gas giants. They are much bigger than Earth and mostly made of gas, but they might have tiny solid cores. These are the outer planets.

These planets formed a really long time ago. Scientists have been studying how planets form for a very long time.

How are planets formed?

Scientists say that the dust around a young star helps make planets. When the Sun (the star of our solar system) was born, it had a big, round disc of gas and dust around it. Most of this disc’s material went into the Sun, but some tiny dust bits stuck together because of gravity. These dust bits turned into small rocks, then into bigger ones sticking together with the help of gas.

In the cold parts of this disc, far away from the Sun, water turned into ice and mixed with dust. These icy bits stuck together, forming big cores for planets. In these cold places, gas slowed down and stuck to the icy and rocky cores, making giant gas planets like Jupiter and Saturn. 

Compared to Jupiter and Saturn, Uranus and Neptune had smaller cores and were placed farther away from the Sun. Due to this, they could not attract much gas, making them much smaller and icier than the other gas giants. Thus, they are also called ‘ice-giants’.

The closer, warmer parts of the disc were where rocky planets like Earth formed. By the time the icy giants were made, not much gas was left for the rocky planets. So, scientists think it took a really long time, maybe millions of years, for planets like Earth to form after the Sun was born.