Compressed data, however, looks like just a jumble of junk unless it is decoded, and the researchers wondered if that would apply to radio signals as well.
"In our paper we proved that there's an equivalent result for radio messages," Newman says. "The most information-rich radio message looks like thermal radiation, which is the standard kind of radiation that we see in the sky. So that would make it difficult to tell the difference between an intentional transmission that was very efficient and just natural phenomena."
But what if someone out there really is trying to contact us? That message would not likely be encoded because they -- whoever "they" might be -- would want us to understand it.
"Then, of course, you could easily see it," Newman admits.
Which takes me back about a dozen years to a time when I sat on the porch of Frank Drake's California home and listened to this eloquent scientist talk about the passion in his life, somehow finding ET.
He said all those years ago that routine signals from another planet would spread out as they passed through space, weakening as their footprint grew ever larger. And just as a flashlight grows dimmer with distance, they would probably be far too weak to detect by the time they reached Earth.
But what if someone is beaming a very tightly focused, high-powered transmission directly at us? Surely we could find that pretty easily.
Drake's enthusiasm has always been infectious, but I wondered out loud how long that enthusiasm would last. With trillions of stars out there, how long would he be willing to search? When might he decide that perhaps he was on the wrong track, that perhaps ET is elusive, or isn't interested in our primitive society?
I don't have the notes from that meeting, and couldn't reach Drake for this column, but I remember what he said. Picking a number out of the air, he said if scientists hadn't found anything in about 10 years, perhaps they would have to rethink their program.
The SETI Institute in Mountain View, Calif., which Drake helped found, has now grown into a large organization of more than 100 scientists and staffers, due largely to the largess of a number of folks with very deep pockets.
It is more than 20 years old now.
And in all those years of searching, not a single signal has turned out to mean anything at all. If ET is trying to reach us, she must not be trying very hard.
Lee Dye's column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.