In the sixth century B.C.E., the Greek philosopher Anaximander theorized that Earth was at the center of the cosmos. That idea became ingrained in scientific thinking and Christian religious beliefs for more than one thousand years. Defiance of church doctrine could mean death, so no one dared dispute this long-accepted idea. No one except a handful of courageous scientists. In the 1500s and 1600s, men like Nicolaus Copernicus, Johanned Kepler, Galileo...