A man of inspiration and vision, astronomer Carl Sagan (1934-1996) taught the world about the wonder of science.

"The cosmos is all that is or ever was or ever will be," he said.

In 1980, his 13-part PBS series Cosmos sparked our curiosity and dazzled our imagination about the incredible possibilities of the universe. Sagan made us look up and dream.

"When you make the finding yourself, even if you're the last person on Earth to see the light, you'll never forget it," he said.

A respected scientist in biology and astrophysics, Sagan discovered that the atmosphere of Venus is extremely hot and dense. Always an outspoken believer of extra-terrestrial life, he worked with NASA on the Mariner, Viking, and Voyager exploration missions.

"In the deepest sense," he explained, "the search for extraterrestrial intelligence is a search for ourselves."

"We are the product of 4.5 billion years of fortuitous, slow, biological evolution. There is no reason to think that the evolutionary process has stopped. Man is a transitional animal. He is not the climax of creation," he wrote poetically in The Cosmic Connection.

Sagan won the 1978 Pulitzer Prize for nonfiction with The Dragons of Eden: Speculations on the Evolution of Human Intelligence.

Known for his self-deprecating humor, he once said about public opinion, "They laughed at Einstein. They laughed at the Wright Brothers. But they also laughed at Bozo the Clown."

There is no end to the possibilities.