Question: hi the earth spins on its axis what make the earth spin?

Louise Dash answered on 23 Jun 2010:

Hi vijaldm!

The earth spins because of the way it was formed. The planets formed from dust and rock orbiting around the sun left over from the formation of the sun in an explosion. These particles are moving (because of the explosion) and are gravitationally attracted to each other so start to form into clumps.

There’s a law of physics that says that momentum has to be conserved, so something that’s moving/spinning will carry on until something acts to stop it – and so all the clumps went on spinning, and formed into a flat plane called an “accretion disk” around the sun (this is why all of the planets are in the same plane!). The clumps attracted each other, formed into bigger and bigger clumps, and eventually became the planets – still spinning.

The earth is still spinning, because there’s no friction in space to slow it down.

Strangely, Venus spins in the opposite direction to the other planets, and scientists think this is because it collided with something early on in the formation of the solar system that gave it enough momentum to start spinning the other way round.