Page:Concepts for detection of extraterrestrial life.djvu/15

Rh Scientists, in fact, can duplicate many of the individual steps through which they think life first arose. But they cannot (or cannot yet) reconstruct the actual process by which life originated, a process which may have occupied Nature for hundreds of millions of years.

At some point energy and chemical materials combined under the right conditions and life began. Nucleic acid molecules were probably formed as well as other complex molecules which enabled the nucleic acids to replicate. Due to errors in replication, or mutations, evolution occurred, and in time many different life forms arose. Since this happened on Earth, it is possible that it also happened on other planets.

The NASA program of space exploration for the next few decades holds great promise of solving one, and of throwing light on the other, of these great twin mysteries—extraterrestrial life and the origin of life. American space technology is now developing the capability of exploring the Moon and the planets of our solar system to search there for organic matter and living organisms.

Spacecraft have flown past, and crashed on, the Moon. Mariner II, launched from Cape Kennedy on August 27, 1962, flew past Venus on December 14, 1962, taking readings and transmitting data which are significant in the search for extraterrestrial life. Mariner’s measurements showed temperatures on the surface of Venus in the order of 800° F, too hot for life as known on Earth.

Other flights past Venus and to Mars are planned. Later, instruments will be sent to Mars in search of extraterrestrial life or biologically significant molecules. Culture media, microscopes, and chemical detecting devices will search out micro-organisms and life-related substances. Eventually, television cameras will look for foliage—and, who knows, footprints?