View by:








What is SETI - the Search for Extraterrestrial Intelligence? Perhaps it is best to start by saying what SETI is not. It is also not an investigation of UFOs or alien abductions. It is not a religion, or worse, a cult. And, perhaps unexpectedly, it is not actually a way of directly detecting intelligent life elsewhere in the universe. More about that later.

What is SETI? SETI is a suite of scientific explorations that attempt to answer the question, “Are we alone?” in the universe by doing experiments. It is the product of our anthropocentric experience and our limited understanding of the universe that we inhabit. It is an endeavor practiced by very pragmatic people. It is potentially a multi-generational exploration. It is not possible to predict when or if SETI will be successful. But, most of all, SETI is very important.

As an experimental exploration, what are the appropriate experiments? One possibility is active experiments, physically going to places where life might be found and then looking. We have visited the Moon and will likely visit Mars in this century. Such physical exploration is fine for the solar system, but the stars are too far away. This situation leads to passive experiments, remote sensing of distant environments. This is what SETI is really all about.

At the same time SETI investigators try to keep an eye out for unexpected things. There could be little nanoprobes in our local environment or other extraterrestrial artifacts. More likely there could be the sorts of anomalies in our astronomical data that could turn out to be as fruitful as those little bits of scruff that Jocelyn Bell found when she discovered the first pulsars.

Contributed by: Dr. Jill Tarter and Jim Miller

Cosmic Questions

Are We Alone? Topic Index
What is SETI?


Life in the Universe
Detecting Intelligence
Electromagnetic Signals
Sky Surveys: Serendip IV, BETA and Argus
Targeted Search: Project Phoenix
A Pseudo-interferometer
Plans for the Future


Jill Tarter

Related Media:

Is There Intelligent Life Elsewhere in the Universe?
Did the Universe Have a Beginning?
Was the Universe Designed?
Are We Alone?
Interview Index
Hubble Deep Field Animation
  Media Index

Other Resources:

Glossary Terms
Bonus Material Home...