**Ask a monkey a physics question thread**

[MadMojoMonkey]

I feel like I'm following a little bit here and there. So to put it simply, that guy floating out into space in Gravity would fall into (an orbit around) the Sun, unless by freak accident he happened to bang into the Moon or Jupiter, with these being dependent on the trajectory.

Yep.

Now, intuitively I'd think it's far more likely to either a) get sucked into something or b) get thrown out, but seeing all of them planets and moons on fairly stable orbits, would it be more likely to end up on collision course/get thrown out of the Solar system or end up eternally encircling something? And why is this?

It's really hard to say. The initial trajectory makes all the difference. As packed as the solar system is, it's still mostly empty, and generally in a plane called the ecliptic plane. An orbit exists in a plane. All the planets' planes are within about 7 degrees of making a single flat plane. Pluto is about 17 degrees off from Earth. If your initial trajectory isn't near that plane, then it's really unlikely you'll hit anything.

The typical way things go is that in the early stages of planet formation, bigger bodies tend to interact with smaller bodies such that the bigger body moves into a closer orbit and the smaller body gets flung out. That is probably due to these bodies forming out of the same swirling mass of gas and dust in the pre-solar nebula. When you impose a random trajectory on this, I think it all evens out as to what possible interactions there are.

Whether or not you'll escape the Earth is a matter of whether or not your speed is greater than the escape velocity for Earth. This is also true for the Sun, but it's a new relative speed and a new escape velocity. Then again for Sagitarius A*.

Like how precise do the velocities need to be for satellites and the ISS to remain up there, and not fling out or crash down?

Orbits are weird.