We might be looking for the wrong thing

Our expert voices conversation on "How to look for alien life."

While Hollywood has defined the standard, iconic alien — an anorexic, almond-eyed gray guy — there's no reason that intelligent extraterrestrials should so closely resemble humans. Of greater importance, the ones we seek might not be living creatures at all.

Humans are busy inventing artificial generalized intelligence — machines that are our cognitive equals, and soon our superiors. Based on this technological arc, it's reasonable to assume that advanced aliens have done this long ago. But such thinking machines are not restricted to planets or other habitats conducive to biology.

Why it matters: Our searches for cosmic company generally use large antennas to search for faint, deliberately produced radio signals from other worlds that are likely to be similar to Earth. We assume that the aliens need what we need — a watery world and a thick atmosphere. But if the aliens are not biological, then we need to modify our search strategies. The most impressive intellects of the universe won't need the life-friendly environments of planets, and could be spread throughout space. The real extraterrestrial's may not be little gray men, but little gray boxes.

The other voices in the conversation:

• Paul Sutter, astrophysicist, Ohio State University: What planets need for life
• Ellen Stofan, planetary geologist and former chief scientist, NASA: Earth as the guide in search for alien life
• Eric Schulze, molecular biologist and former policymaker: Alien life is closer than you think