# What is the distance between the Earth and Sun?

Distance from the Sun to Earth is about 147.2 million km or 93 million miles. This distance between Earth and Sun is also known as AU or Astronomical Unit. It’s a primitive element that comes in handy to find the distance between the earth and unknown planets, Stars, etc. For a measurement, tape to measure a table length. Here 1AU is the measurement scale.

# How can we measure the distance between the earth and the sun?

Since 1961, after the discovery of radar, scientists have been using this device to measure the distance between planets. Before that, astronomers rely on trigonometry and another relative planet Venus. Venus and the earth revolving the sun in the same plane; that’s why they choose Venus for this calculation, and I hope you know why they choose trigonometry.

Because they two revolve around the same plane, at some point, Earth-sun-venus will come at 90 degrees(as shown in the image). Where the game begins; The distance between the earth and Venus is determined as a*cos(e). With little more calculation, we find the distance between the Sun and Venus as a*sin(e). Here e is the sun-earth-venus angle.

The famous astronomer Aristrachaus calculated this geometrical measurement method. His reasoning is correct, but the measurement is wrong…