In what ways are the inner planets different from the outer planets?

The Sun was once very bright and radiant, managing to drive away almost all of the gas from the inner solar system, leaving only the rocky cores. However, the Sun was not radiant enough to drive away this gas from the outer planets, so over time, as the gas was already present in the outer solar system, these rocky cores managed to accrete mantles of gas. This is why the outer planets are mostly composed of gases, mostly hydrogen and helium. The formation of the planets took place nearly 4.5 billion years ago, from a rotating, spherical cloud of diffused gas, which collapsed primarily due to the gravitational effect of a nearby event like a dying star.

The inner planets have greater temperatures than the outer planets because of their closer proximity to the sun. They also rotate more slowly than the outer planets.

The inner planets, also known as terrestrial planets, are Mercury, Venus, Earth, and Mars. They are smaller, denser, and have solid surfaces. The outer planets, also called gas giants, are Jupiter, Saturn, Uranus, and Neptune. They are larger, less dense, and composed mainly of gas.