Table of Contents
What factors determine a planet?
It says a planet must do three things:
- It must orbit a star (in our cosmic neighborhood, the Sun).
- It must be big enough to have enough gravity to force it into a spherical shape.
- It must be big enough that its gravity cleared away any other objects of a similar size near its orbit around the Sun.
How is the shape of a planet determined?
A planet is round because of gravity. A planet’s gravity pulls equally from all sides. Gravity pulls from the center to the edges like the spokes of a bicycle wheel. This makes the overall shape of a planet a sphere, which is a three-dimensional circle.
What caused different type of planets to be formed?
The various planets are thought to have formed from the solar nebula, the disc-shaped cloud of gas and dust left over from the Sun’s formation. The currently accepted method by which the planets formed is accretion, in which the planets began as dust grains in orbit around the central protostar.
Why all planets are in round shape?
Planets are round because their gravitational field acts as though it originates from the center of the body and pulls everything toward it. The only way to get all the mass as close to planet’s center of gravity as possible is to form a sphere. The technical name for this process is “isostatic adjustment.”
How did the planetesimals form planets?
The Birth of the Planets. Each planet began as microscopic grains of dust in the accretion disk. The atoms and molecules began to stick together, or accrete, into larger particles. By gentle collisions, some grains built up into balls and then into objects a mile in diameter, called planetesimals.
How did the Earth and other planets form?
The Sun and the planets formed together, 4.6 billion years ago, from a cloud of gas and dust called the solar nebula. A shock wave from a nearby supernova explosion probably initiated the collapse of the solar nebula. The Sun formed in the center, and the planets formed in a thin disk orbiting around it.
How is the mass of a planet determined?
Based on what we have learned about orbits and the Newtonian laws of physics, we can calculate the mass of a planet based on the effect it has on its parent star. As a planet orbits a star, there is a minuscule pull on the star caused by the mass of the planet’s movement.
How are the different types of planets formed?
Since different materials condense at different temperatures, our solar system formed different types of planets. The dividing line for the different planets in our solar system is called the frost line. In the simulation below, notice where hydrogen and helium condense in the solar nebula.
How long does it take for a planet to form?
In the warmer parts of the disk, closer to the star, rocky planets begin to form. After the icy giants form there’s not a lot of gas left for the terrestrial planets to accrete. Planets that are rocky like Mercury, Venus, Earth and Mars may take tens of millions of years to form after the birth of the star.
How can you determine the properties of a planet?
Before you can do any sort of comparison of the planets, you need to know how far away they are. Once you know their distances, you can determine basic properties of the planets such as mass, size, and density. Distances