eli5: When probes are released into space they start to spin. What gives every object in space this momentum to rotate? Would it be possible to send something to space and release it very cautiously so it won’t get any energy from the releasing spacecraft and the object hence wouldn’t rotate?
In: Physics
Are you talking about spinning around is own axis or “spinning” (orbiting) around the earth, the sun, or some other body in the solar system?
Spinning around its axis has been a way to stabilize some rockets and even some probes but it is not a requirement to do that. Most satellites are stabilized so they point on the same side toward earth. That is technically spinning one around its own axis per obit.
When you launch a satellite to orbit the earth it does that because you accelerate it you 7.5km/s parallel to the surface of the earth for low earth orbit, The majority of the rocket is used do this.
If you just go straight you will fall back down. The energy to go up to the altitude of the low orbit is a lot lower than is required for an orbit. The needed acceleration is around 2km/s compared to the total of around 9.5km/s for low earth orbit.
You can launch straight up and if it sends you far enough you will be out of earth’s gravitation influence and orbit the sun. Earth orbit the sun at 29km/s the acceleration you have done is added or subtracted from that. It is not that different than if you throw a ball in an aircraft the ball will move at the speed of you + the speed you throw the ball.
You need to accelerate so you move at 29km/s in the opposite direction of Earth’s orbit to have an orbit around the sun. That acceleration is higher than needed to get out of the solar system if you do it in the other direction- So it is harder to get the sun compared to Pluto and beyond because you start with the motion of the earth.
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