how did figure out the distance from the sun to earth?

Question

how did figure out the distance from the sun to earth & the distance between planets??

Answer 1

I believe the first method was to use the parralax method. They triangulated the Sun's (or planets) position using two different points where the earth was in its orbit, i.e. summer and winter. This is similiar to the method GPS satelites triangulate your position on earth.

Now they can use RADAR and lasers to more accuratley calculate distances.

Answer 2

Kepler's laws tell you the RATIOS of the distances of all the planets, so if we could just find the distance between any two planets, we know them all. The first attempts were to find the distance to Venus when it crossed on front of the Sun by triangulation based on observations from widely separated parts of the Earth. But Venus is too far away, so the results were not that accurate. Later a better measurements was obtained by observing an asteroid that passed closer to Earth than Venus ever does. In modern times, we use radar and space craft to get extremely accurate measurements.

Answer 3

We can measure the time it takes to send & receive a (radar) signal to Mars or Venus and determine the distance.

Also parallax.

Also the distance of various planets from the sun can be computed with Keplers laws of motion since we know the orbital period .

Answer 4

A very long measuring stick.