What is the radius and diameter of the Sun that Aristarchus found?
Aristarchus, Greek: 310 BC – ca. 230 BC was a Greek astronomer and mathematician, born on the island of Samos, in Greece. He was the first person to present an explicit argument for a heliocentric model of the solar system, placing the Sun, not the Earth, at the center of the known universe. Aristarchus concluded that the Sun was 19 times farther away than the Moon. The Sun’s distance is actually about 390 times the Moon’s. Aristarchus pointed out that the Moon and Sun have nearly equal apparent angular sizes and therefore their diameters must be in proportion to their distances from Earth. He thus concluded that the diameter of the Sun was about 20 times larger than the diameter of the Moon; which, although wrong, follows logically from his data. It also leads to the conclusion that the Sun’s diameter is almost seven times greater than the Earth’s. Aristarchus introduced six hypotheses, from which he determined first the relative distances of the sun and the moon, then their relative
