Earth is a rocky planet, and third planet from the yellow star known as Sol or just the "Sun" which Earth orbits, and the densest and fifth-largest of the eight planets, not counting the one dwarf planet Pluto, in the Sol System. Earth is home to humans, the planet's dominant intelligent species.
In Superman/Batman Vol 1. #50, Kryptonian scientist Jor-El sent a probe to Earth that made contact with a human known as Thomas Wayne while on a drive with a pregnant wife, the probe holographically transmitting Thomas' consciousness to Krypton so that Jor-El could better learn what kind of world Earth was to help him decide which of many possible candidates he should send his son to. Thomas told Jor-El that the people of Earth aren't perfect, but are essentially a good and kind race who would raise the child right, convincing Jor-El to send Kal-El there. Thomas recorded his encounter in a diary, which was discovered by his son Bruce Wayne in the present day.
Jor-El decided to send Kal-El to Earth, realizing he would gain superhuman powers under Earth's more intense yellow sun and lower gravity. As Krypton finally went through its final destructive stages, Jor-El and Lara placed their son in the rocket and launched him toward Earth. Kal-El landed on the North American continent in one of the Earth's nation states the United States of America. He was recovered by two humans known as Martha and Jonathan Kent outside the town of Smallville, Kansas. The couple adopted him and raised him at the home on the Kent Farm. He was renamed Clark Kent and brought up on Earth to one day become the planets protector "Superman".