Page:Concepts for detection of extraterrestrial life.djvu/11



The mystery of his own origin has intrigued man since earliest antiquity. Throughout the ages he has puzzled and theorized over the question of how he began, where and when.

But man is like a detective arriving at the scene some millions or billions of years after the event and trying to reconstruct the event. The principals have long since departed; most of the clues have disappeared; even the scene itself has changed.

Of equal fascination today is the question of life on other worlds—extraterrestrial life. Do the seasonal changes in the darkening on the Martian surface mean that plant life blooms, withers, and dies there? Are there living things beneath the covering clouds of Venus despite the great heat this planet is subjected to? Did life on the Moon go underground eons back when the atmosphere departed; and does life, or its residue, still exist there? Is Jupiter actually ice encrusted beneath its hydrogen shroud; and if it is, does this preclude some form of life undreamed of by man?

Now, for the first time, man is beginning to grasp the key which may solve the question of whether or not life in some form exists on the other celestial bodies of our solar system. The key is, of course, the technology of space exploration. The search for life in space now being planned by the National Aeronautics and Space Administration is part of that technology.

The question of extraterrestrial life and the question of the origin of life are interwoven. Discovery of the first may very well unlock the riddle of the second.

The oldest form of fossil known today is that of a microscopic plant similar in form to common algae found in ponds and lakes. Scientists know that organisms like it flourished in the ancient seas over 2 billion years ago. (See fig. 1.) However, since algae are a relatively complex form of life, it is obvious 1