Who first measured the distance from the Earth to the sun?
1 Answer
Explanation:
The ancient Greek Aristarchus calculated the distance between the Earth and the Sun in around 300BC. He used measurements of the parallax of the Moon to do this. His measurements were not accurate and his results were very wrong.
The key to measuring the distance to the Sun is measuring the distance to another planet when it is at its closest to the Earth. Once the distance is known the Earth-Sun distance can be calculated using geometry or Kepler's third law.
In 1672, Giovanni Cassini and John Flamsteed independently measured the distance fro Earth to Mars by taking parallax measurements. They calculated the distance to be 87 million miles which is quite close to the actual 93 million miles.
In the 1960s the accuracy was improved by bouncing radar signals off the planet Venus and measuring the time taken for the signal to return.
