How are distances between Earth and other planets/stars calculated?
Well, for solar system objects orbiting our Sun, it’s easier to calculate the objects distance from the Sun. For Pluto,, you would discover it, track it’s movements over time, and come up with an “orbital period” how long it takes to orbit the Sun. From there, you could use Kepler’s Third Law to figure out its distance from the Sun. Subtract 1AU from that number when it is at opposition, and you know it’s distance. For stars, parallax is used (triangulation). Using half the orbit of the Earth as a 2 AU baseline and measuring the tiny little shift against more distant background stars to calculate the parallax, and calculate the distancee.
