# How was measured distance to the sun in ancient times?

Science 0 CommentsWho were the first who tried to measure distances in the universe, and what techniques were used?

those that tried to determine distances in space – including the distances from Earth to the moon and the sun. He did in ancient times only by measuring angles.

The lack of reliable instruments did, however, that his results were quite inaccurate, even if the measuring principle has proved to be completely correct.

Aristarchus concluded that the distance from the Earth to the Sun was 19 times greater than the distance from Earth to the moon. The correct factor was subsequently found to be around 390.

**A little help from Crescent**

When the measurement used Aristarchus, who lived 310-230 BC, the fact that the angle between the lines of sight the moon-sun and the moon-Earth is exactly 90 degrees at the half-moon. By measuring the angle between the sight lines of the Earth-Sun and Earth-moon, he could determine the relationship between the distance to the moon and sun.

**Small error with serious consequences**

Aristarchus measured the angle at half moon at 87 degrees, but today we know that the correct value is 89.85 degrees.

This, at least on paper, minimal error of 2.85 degrees had major consequences, since the results are extremely sensitive to even small errors in angle measurement. With the correct value of the ratio is about 20 times greater than that Aristarchos reached.

Error measurement of the angle is probably because halvmånfasen not last more than a moment. Without modern measuring phase is very difficult to hit accurately. The moon moves constantly around the earth, while the earth moves around the sun. Therefore, changing the angle Aristarchus would measure all the time.