We measure space objects speed in relation to earth. But since earth is also moving through space, how do we know the true speed of objects without a universal “non moving” point?

Question

The speed of an object is measure relative to the observer. But since all objects are moving in relation to all objects, how can we know the true speeds of things? Wouldnt two observers on different planets measuring an object in space come up with different answers?

In: Physics

Answer 1

A teacher I had in college brought up this, basically poking fun at Star Trek. In the show they would say full stop, but full stop compared to what? If Earth, then what ever your trying to look at would zoom past you. He liked pointing out that speed is just like time, a concept made up by humans that ultimately means nothing to the universe.