The Search for Alien Life

The Search for Alien Life (October 2002)
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Are we alone in the universe? It's a question that every school kid has probably asked at some time-and scientists in particular want an answer. In their quest after alien beings, astronomers have scanned the heavens for radio signals from another technologically advanced civilization; they've sent probes to all but one of the planets around our Sun; they've studied extreme life forms on Earth to better understand the conditions under which life can take root; and they've scrutinized the neighborhoods around distant stars.

We may never discover whether or not extraterrestrials exist-at least not until they contact us. But researchers continue to refine their search. Discoveries that water likely flowed on Mars at one time and that Jupiter's moon Europa may house a subterranean sea have intensified the hunt for alien organisms in our own solar system. And the identification of approximately 100 extrasolar planets in recent years has raised hopes of finding inhabited worlds similar to Earth elsewhere in our galaxy.

In this exclusive online issue, Scientific American authors review the evidence for and against the existence of ETs. In Where Are They?, Ian Crawford ponders what it means that all of our surveys so far have come up empty handed. In Is There Life Elsewhere in the Universe?, Jill C. Tarter, director of research for the Search for Extraterrestrial Intelligence (SETI) Institute, and her colleague Christopher F. Chyba assert that the search has only just begun. Other articles examine the cases to be made for relic life on Mars and other bodies in our solar system, as well as the plans to launch a new space telescope for spying on distant worlds. Buy the issue, read the articles and, the next time you gaze up at the night sky, make up your own mind. --The Editors

Cover; The Search for Alien Life; by Staff Editor; 1 Page(s)

Table of Contents; The Search for Alien Life; by Staff Editor; 1 Page(s)

Where Are They?; The Search for Alien Life; by Ian Crawford, sidebar by Andrew J. LePage; 6 Page(s)

Maybe we are alone in the galaxy after all (originally published July 2000)

Is There Life Elsewhere in the Universe?; The Search for Alien Life; by Jill C Tarter and Christopher F. Chyba; 6 Page(s)

The answer is: nobody knows. Scientists' search for life beyond Earth has been less thorough than commonly thought. But that is about to change (originally published December 1999)

Profile: Jill C. Tarter, An Ear to the Stars; The Search for Alien Life; by Naomi Lubick; 2 Page(s)

Despite long odds, astronomer Jill C. Tarter forges ahead to improve the chances of picking up signs of extraterrestrial intelligence (originally published November 2002)

Searching for Life in Our Solar System; The Search for Alien Life; by Bruce M. Jakosky, sidebar by Richard Lipkin; 5 Page(s)

If life evolved independently on our neighboring planets or moons, then where are the most likely places to look for evidence of extraterrestrial organisms? (originally published in Magnificent Cosmos-Spring 1998)

Searching for Life on Other Planets; The Search for Alien Life; by J. Roger P. Angel and Neville J. Woolf, sidebar by Corey S. Powell; 7 Page(s)

Life remains a phenomenon we know only on Earth. But an innovative telescope in space could change that by detecting signs of life on distant planets (originally published April 1996)

The Case for Relic Life on Mars; The Search for Alien Life; by Everett K. Gibson, Jr., David S. McKay, Kathie Thomas-Keprta and Christopher S. Romanek; 7 Page(s)

A meteorite found in Antarctica offers strong evidence that Mars has had - and may still have - microbial life (originally published December 1997)