Using the parallax of an asteroid can be used to determine the scale of the Solar System and distance of the sun. In 1931, Eros approached within 16 million miles of Earth, closer than any planet. Fourteen observatories in nine countries tracked it. After the decade that followed, the distance of the sun was determined to be 93,005,000 miles.
A visual chronology of Asimov's ~1500 scientific inventions and discoveries.
