A telescope toppled an old universe

Copernicus proposed a heliocentric model with the Sun near the center, but Ptolemy’s geocentric system still ruled. Aristarchus had even proposed a heliocentric cosmos long before—and was rejected.

From Ptolemy to Galileo: How Heliocentrism Won

Why Copernicus didn’t win—yet

His model eliminated the equant, which astronomers praised, but it didn’t displace Ptolemy’s.

From Ptolemy to Galileo: How Heliocentrism Won