Question

how a asteroid get move in the space

Answer 1

By the no gravity in space asteroids tend to get pressurized

Answer 2

Asteroids move because of gravity. Isaac Newton pretty much started physics and he said that if something is moving, it will continue to do so until something (air resistance, friction, brick wall) stops it moving. In space there is no air, so the asteroids first get their initial push from something exploding or dust clouds sticking together and then nothing stops them. The only thing that affects them is gravity, which pulls on them so they move in orbits. I don’t know if you’ve ever seen one, but sometimes you get these large curved bowls that you drop a coin in and it runs round in circles till it reaches the hole then drops out of sight. This is a little bit like how space works except that there is no friction to slow the coin and so it goes on forever until it accidently crashes into something.