How do you measure stuff in space? How do we know this star weighs x-times the weight of the sun? And how we know how much the sun weights. Same goes for distances. How can you tell how far something is?

Question

How do you measure stuff in space? How do we know this star weighs x-times the weight of the sun? And how we know how much the sun weights. Same goes for distances. How can you tell how far something is?

In: Physics

Answer 1

Once you know the distance to a double-star, or multiple-star, system, you can determine the absolute size of the stars’ orbits. Add knowledge of their periods, and you can determine their masses.