10-THE UNIVERSE

10-THE UNIVERSE 

IN THE SECOND CENTURY A.D., THERE WAS A FAMOUS GREEK ASTRONOMERNAMED PTOLEMY. HE BELIEVED THAT THE EARTH WAS THE CENTER OF THE UNIVERSE. THEOTHER PLANETS AND THE SUN MOVED AROUND THE EARTH. PEOPLE ACCEPTED THIS BELIEFUNTIL THE MIDDLE OF THE 1500S. A POLISH ASTRONOMER NAMED NICOLAUS COPERNICUSSAID THE EARTH WAS NOT THE CENTER OF THE UNIVERSE. THE SUN DID NOT REVOLVEAROUND IT. INSTEAD, THE EARTH—AND ALL THE OTHER PLANETS—REVOLVED AROUND THE SUN. HE WAS RIGHT. BUT IT TOOK MANY YEARS BEFORETHIS FACT WAS ACCEPTED.