How is the distance between Earth and Venus calculated?

The greatest elongation of Venus is about 46 degrees, so by this reasoning, the Sun-Venus distance is about 72% of the Sun-Earth distance. Similar observations and calculations yield the relative distance between the Sun and Mercury. (However, Mars and the outer planets are more complicated.). read more

The distance between the Earth and Venus varies widely during the year (Earth’s year) because both planets are in orbit around the Sun. Because Venus is closer to the Sun it whizzes around faster than the Earth, and of course, the planets may be widely separated if they happen to be on opposite sides of the Sun. read more

Venus passes in between the earth and the sun.Two people would observe from different points on earth ,Venus transiting the sun.The angle formed by this observation and by using Kepler s third law, it is possible to measure the distance bw earth and sun .This is the astronomical unit itself. read more

Once this Earth-Venus distance is known, the distance between Earth and the Sun can be calculated. As you have indicated, once the distance between Earth and Sun is known, one can calculate all the other parameters. We know that the Sun, as seen from Earth, has an angular diameter of about 0.5 degrees. read more