6. Are We Alone?

If only we could click our heels and be swept off to another Earth, we'd know. Meanwhile, we're all stuck here on this planet with arguably lousy cosmic eyesight, forced to indirectly detect the presence of worlds around other stars, left to wonder if they might harbor life.

So far the worlds we find are huge, most bigger than Jupiter. Prior to 2002, every one of them orbited so close to its host star as to be decidedly strange by the standards of our solar system. This forced us to question whether ours is standard at all.

In June, however, new "Jupiters" were found in orbits similar to our own beloved gas giant.

Now the pressure is on to find smaller planets, and one study this year estimated there are billions of them out there. Few doubt the presence of at least some rocky planets in Earth-like orbits. But don't bet on any proof coming 2003. This is a mystery that probably won't be solved until a new generation of space telescopes goes into orbit, mid-decade at the soonest.

Meanwhile, another study this year estimated the chances for extraterrestrial life on Earth-like planets is 1-in-3.

Most scientists, when they talk about ET, would be thrilled to find microbes. The folks over at the SETI Institute, on the other hand, are listening for intelligent life, perhaps animals like us (or really smart microbes). While they may never get a signal, it could happen in 2003.

Next Page: The enigmatic Sun