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Who's Out There?

Are we alone? Are we humans the only ones in the universe gazing up from our planet and asking, Who else is out there?

It could be that, out among the billions of stars, there are other planets with other living creatures. And among those creatures, there could be intelligent ones, wondering if there's life on Earth!

People have been pondering these questions for centuries. Only now, in the age of powerful telescopes like the Hubble, can we begin to answer them.

A Historic Discovery
January 17, 1996, may go down in history as a very important date in the search for these answers. On that day, two U.S. astronomers announced that they had discovered two planets traveling around distant stars that are similar to our sun. These are the first planets detected outside our solar system that could possibly support life (see TFK, 1/26/96).

The two planets, discovered by Geoffrey Marcy and Paul Butler of San Francisco State University, are nothing like Earth. Humans could never live there. The planets appear to be more like Jupiter: giant, stormy balls of poisonous gases with cores of solid rock. But high up in their atmospheres there may be the key ingredient for life as we know it: liquid water.

If creatures do live on these planets, they would be very different from us. They might look like balloons! They might spend their entire lives in the upper atmosphere without ever touching solid ground.

Right now we cannot tell whether there is life or even water on the new planets. They are too far away to be studied by today's instruments. But the discovery of these planets--one orbiting a star in the Big Dipper, the other traveling around a star in the constellation Virgo--suggests that there may be many more planets out there.

Now the race is on to find them. The excitement about this field "is beyond belief," says Daniel Goldin, head of the National Aeronautics and Space Administration (NASA).

The Race To Find Planets
Finding new planets is no easy job. Even the biggest planets are small compared with stars, and they do not burn brightly. To find them, astronomers must look carefully at stars and watch for telltale wobbling patterns. From the patterns they can calculate whether a large planet-like object is orbiting the star and pulling on it with its gravity.

Astronomy is a competitive game. Right now Butler and Marcy are racing against a Swiss team and others to find more wobbling stars, more planets. "Very shortly," predicts Butler, "there could be more planets known outside the solar system than inside!"

Finding planets should get easier over the next five years, thanks to a brand-new NASA project called Origins. It will launch a new generation of space telescopes to search for other worlds. By the year 2010, NASA hopes to put five telescopes in orbit out by Jupiter. The telescopes would work together like one gigantic scope. Instead of detecting just giant planets, they should be able to find planets the size of Earth. Such planets are more likely to support life than the gas giants.

NASA chief Goldin dreams of the day when new space telescopes will allow Earthlings to see distant planets in glorious detail: oceans, mountains, maybe even cities.

Listening For E.T.
In the meantime, if astronomers can't see other worlds, they can listen for them. For 35 years scientists around the globe have participated in the Search for Extra-Terrestrial Intelligence. SETI (rhymes with Betty) uses giant dish-shaped radio antennas to listen for signals from outer space. The idea is that somewhere out there aliens may exist who know how to send radio signals.

The most advanced seti station is in Boston. It is headed by Harvard physicist Paul Horowitz. No seti station has yet detected an alien's signals, but Horowitz is not discouraged.

"Intelligent life in the universe?" he asks. "Guaranteed. Intelligent life in our galaxy? Overwhelmingly likely." So why haven't we heard from aliens yet? Maybe our equipment isn't sensitive enough, says Horowitz, or we haven't tuned to the right radio signal.

So E.T., if you're out there, please adjust your transmitter. We Earthlings are all ears!

Next: First Lady On The Spot