Logo IMG
HOME > My Amsci > Restricted Access

Alone in the Universe

Restricted Access The content you've requested is available without charge only to active Sigma Xi members and American Scientist subscribers.

If you are an active member or an individual subscriber, please log in now in order to access this article.

If you are not a member or individual subscriber, you can:


2011-07SmithF1.jpgClick to Enlarge ImageThere has often been the assumption, even amongst astrophysicists, that because the universe is infinitely large, there must be somewhere else in it a planet with conditions hospitable to intelligent life. Recent surveys locating a number of extrasolar planets may seem to bolster this conclusion. The author, however, argues that the new data only reinforces the conclusion that humans are alone in the universe, at least for all practical purposes. Smith points out that even if we were to wait for signals that would not reach us for 100 human generations, we still would not be able to detect any messages from farther than 1,250 light-years away, a relatively small pocket of the universe. He goes on to extrapolate from available data on extrasolar planets to conclude that the number of even vaguely suitable stars with possible habitable planets within that distance is slight—and even then, the chances of life evolving to intelligence is much slimmer. He concludes by considering how humans should respond to the idea that even if there is intelligent life somewhere out there, we’ll likely never know about it.

Connect With Us:

Facebook Icon Sm Twitter Icon Google+ Icon Pinterest Icon RSS Feed

Subscribe to Free eNewsletters!

  • American Scientist Update

  • An early peek at each new issue, with descriptions of feature articles, columns, and more. Every other issue contains links to everything in the latest issue's table of contents.

  • Scientists' Nightstand: Holiday Special!

  • News of book reviews published in American Scientist and around the web, as well as other noteworthy happenings in the world of science books.

    To sign up for automatic emails of the American Scientist Update and Scientists' Nightstand issues, create an online profile, then sign up in the My AmSci area.

Read Past Issues on JSTOR

JSTOR, the online academic archive, contains complete back issues of American Scientist from 1913 (known then as the Sigma Xi Quarterly) through 2005.

The table of contents for each issue is freely available to all users; those with institutional access can read each complete issue.

View the full collection here.

RSS Feed Subscription

Receive notification when new content is posted from the entire website, or choose from the customized feeds available.

Write for American Scientist

Review our submission guidelines.

Subscribe to American Scientist