what makes planets rotate while in orbit around there star?

Answer 1

When a figure skater spins and pulls in her arms and legs to a tight axis she spins much faster conserving rotational momentum. If the planet was formed from a cloud of gas (and space stuff?) with any whirl to it, the condensed end mass would spin faster than the materials brought together and in the near-perfect vacuum of space there would be nil friction to slow it down. If the mass was not already orbiting the star it would fall into the star and disappear.

Answer 2

The core of the planets are liquid. The liquid moves faster than the shell, so it keeps the planet turning.

I think the action of the orbit, and/or the magnetic field generated by the moving magnetic liquid contribute to the rotation.

FYI:
The orbit of a planet is actually the planet falling toward its star, but it is going just fast enough to keep missing the star. If a planet went too fast it would reach escape velocity and take off into outer space. If it went too slow it would crash into its star.

Answer 3

Take the formation of planets in steps:

1. The particles (rocks, dust, gas whatever) that are going to make up the planets initially are orbiting in bands, a bit like Saturn's rings.

2. The particles begin to attract one another, firstly by static charge, but as the mass builds up, by gravitational attraction.

3. The material on the outer part of the band moves in, and like the skater pulling in her arms, they speed up.

4. The matter on the inner side, by contrast, moves outward to coalesce with the body of the material, and thus slows down.

5. We thus create a "couple", imparting a rotation in the condensing masses. This will tend to be a rotation in the same direction as the overall orbit, which is what we see in most planets. As the planets increase in mass they maintain this spin.

There will be other factors disturbing the overall picture, but in a nutshell, that's it.

Answer 4

Some don't. It all depends on the gravitational pull of the planet. If one side of the planet is denser than the other (take earth for instance, the water is more dense than the dirt) then it will start the planet in motion. Think about those magnetic things in the mall, once you spin them, they never stop. The same principle applies. Once the planet tilts do to it's density, it just keeps spinning. Of course it would have to have started spinning just after the planet was fully developed. Hope this answered your question adequately.

Answer 5

NASA - Still-Forming Solar System May Have...
... solar system in which all the planets orbit the Sun in the same direction," said ... The disk and the resulting planets...
www.nasa.gov/centers/goddard/news/op_o...
Curious About Astronomy: Why do the...
Why do the planets orbit the sun? Why do the planets rotate around the sun? ... reason why the planets revolve around, or...
curious.astro.cornell.edu/question.php...
Curious About Astronomy? Planets
Why do planets rotate? (Intermediate) ... Why do all the planets orbit in the same plane? (Intermediate) ... most moons...
curious.astro.cornell.edu/planets.php

Answer 6

Obviously the earth can be drawn straight into the sun because of the earth gravity, tangental force, and inward force. It's like if a new video game came in the mail and your older brother had his hands on one end of the video game and you had your hands on the other end and your both pulling on it because you both want to be first to play it. What happens to the video game? It stays stuck between you because you are both pulling on it. Maybe one of you starts spinning around to shake the other one free.

Principia was a book written by either Kepler or Newton describing the laws of gravity relating to planets. Tangental force is the earths momentum it gained when it first formed and the momentum wants to carry it in one direction, but the Suns gravity tugs it gently toward it. Once a celestial body like a planet has momentum, or speed, in a particular direction it will never slow down or change direction unless acted upon by a force, such as gravity.

Answer 7

When Gravity and centrifugal force are in balance then planets rotate around their star

Answer 8

In the earth it is due to the iron/nickel core orbiting, as it has for quite a while, this also gives the earths its magnetism

Answer 9

I am sure its just from when they were formed...they were spinning as they formed and so have just kept spinning to this day. With no friction or resistance of any sort, what is there to stop the spin?

I don't think all planets spin.

Answer 10

the lack of friction, and inertia, and gravitational forces.