NASA Astronomy Picture of the Day Collection

Aristarchus' Unbelievable Discoveries

Here lived one of the greatest thinkers in human history. Aristarchus [ http://www-groups.d…] lived on the Greek island of Samos, a small island in the center of the above picture [ http://images.jsc.n…] that can be identified with a good map [ http://www.cruiseai…]. Aristarchus, who lived from 310 BC to 230 BC, postulated that the planets orbited the Sun [ http://antwrp.gsfc.…] - not the Earth [ http://antwrp.gsfc.…] -- over a thousand years before Copernicus [ http://www-groups.d…] and Galileo [ http://antwrp.gsfc.…] made similar arguments. Aristarchus used clear logic to estimate the size of the Earth, the size and distance to our Moon [ http://antwrp.gsfc.…], the size and distance to our Sun, the the even deduced that the points of light we see at night are not dots painted on some celestial sphere but stars like our Sun at enormous distances. Aristarchus' discoveries [ http://www.perseus.…] remained truly unbelievable to the people of his time but stand today as pillars of deductive reasoning.

Space Shuttle Columbia [ http://antwrp.gsfc.…], STS58 [ http://www.ksc.nasa…], NASA [ http://www.nasa.gov/]

Goddard Space Flight Center (GSFC)

Johnson Space Center (JSC)

Earth

Galileo

Moon

Sun

Perseus

Columbia

Space Shuttle Orbiter

http://antwrp.gsfc.…

SPD-APOD-ap960914