We end up with a planet with an iron core surrounded by rock, and maybe water and ice on the outer edges. Denser materials sink toward the core, and lighter materials float to the planet's surface. A 33 Part (a) Calculate the angular momentum, in kilogram meters squared per second, of the Earth in. (8) Problem 7: The planet Earth orbits around the Sun and also spins on its own axis. Rising pressure in the core then causes the core to melt. (8) Problem 7: The planet Earth orbits around the Sun and also spins on its own axis. Because of the force of gravity, the planet spins faster, like an ice skater drawing in her arms to spin. When the baby planet gets massive enough, the force of gravity begins crushing it, making it denser. As a baby planet starts to grow, it gets heavier, and its gravity attracts more and more little pieces. We think that inside the disk, the gas and dust can stick together in a process called accretion. All of it - the star, the gas, the dust - spins in the same direction.Īstronomers think that our solar system looked a lot like Beta Pictoris in its early years. The star forms, spinning at the center of a flat pancake of rotating gas and dust called a protoplanetary disk.

The force of gravity causes these clouds to tug on one another as they pass, which makes them slowly rotate.Įven when one of these clouds collapses to form a star, it continues to rotate. Every star is born from a cloud of gas and dust that moves through space surrounded by other similar clouds.

Animation of earth spinning on its axis