Journey to the Stars Space Exploration--Tomorrow and Beyond [Paperback]

Robert Jastrow discusses the past and future of space exploration, the cosmic mysteries that still await solution, and the possibility of extraterrestrials whose intelligence far outstrips our own.Introduction
 
If intelligent beings exist in space, and they look in our direction now and then, they will have observed something in recent years that must pique their curiosity. At television and FM frequencies, our planet blazes more brightly in the sky than the sun itself. For the first time in the history of the Universe, the earth has become a conspicuous object in the heavens—a beacon sending signals to every nearby star that intelligent life has arisen on this planet.
 
Some astronomers believe no intelligent beings exist on these stars to receive our message. They believe mankind is alone in the Universe. But other astronomers are unwilling to accept that conclusion. They do not find it credible that, out of all the billions of planets in the Universe around us, only one should have been touched with the magic of life.
 
These astronomers point to the fact that the Universe is 15 billion years old, but the sun and the earth are only four and a half billion years old. It follows that if other solar systems contain intelligent life, this life must, on the average, have evolved at least a billion years beyond mankind.
 
Reflecting on the fact that the human brain has doubled in size in the last million years, the astronomers say to themselves: Beings whose evolution has carried them a billion years beyond the human level may possess great heights of brainpower; how interesting it would be to speak to them, and find out what they have learned in that long interval. The greatest thinkers in human history might be as children in their presence. “In their eyes,” one observer suggests, “Einstein would qualify as a waiter and Thomas Jefferson as a busboy.”
 
How long must we wait beforel]