What is the scientific reasoning for the order of the planets?

Question

Matthew Arnold · Accepted Answer

The order of the planets is partly due to where they were formed and partly from the evolution of the Solar System.

The planets began to form after the Sun was formed, which was created from a nebular of gas and dust that collapsed under the force of gravity. The remnants of the nebula formed an accretion disc around the Sun, where dust grains orbiting the Sun collided and began to clump together. The clumps continued to collide to form the four inner rocky planets, Mercury, Venus, Earth, and Mars. In the region within about 4 AU of the Sun, it was too hot for volatile compounds to condense. The rocky planets moved to larger orbits because of friction with other material in the disc they were forming in, which caused them to form closer to the Sun than they are today. More dwarf planets would have been present in the early Solar System; one roughly the size of Mars is assumed to have collided with Earth to form the Moon. It is beyond the orbit of Mars that is cool enough for compounds like water and methane to be solid enough to start the clumping together process, which is how the giant planets Jupiter, Saturn, Uranus, and Neptune formed. It is believed that Uranus and Neptune formed further inwards and migrated outwards to their current positions, and that the giant planets—Saturn in particular—interact gravitationally with each other. Jupiter is thought to have formed further out and migrated inwards to its current position.

Cooper Ann · Answer

undefined The solar system's planets are arranged in a particular order according to how far apart they are from the Sun. Mercury is the planet closest to the Sun, while Neptune is the planet farthest away.