The hunt for extraterrestrial life should be dramatically expanded, a panel of scientists convened by the country’s leading scientific advisory group said today, to include what they call “weird life,” organisms that lack DNA or other molecules found in life as we know it.

“The committee’s investigation makes clear that life is possible in forms different from those on Earth,” the scientists concluded. Their report, “The Limits of Organic Life in Planetary Systems,” was published today by the National Research Council of the National Academies of Sciences and posted on the NAS web site, www.nationalacademies.org.

Other experts hailed the report as an important rethinking of the search for life. “It’s going to help us a lot to make sure we go exploring with our eyes wide open,” said Michael Meyer, the Mars exploration program lead scientist at NASA.

Starfish, sequoias, salamanders, and the rest of Earth’s residents seem very diverse. But they’re surprisingly similar on the molecular scale. Every species scientists have studied needs liquid water to survive, for example. They all rely on DNA to carry genetic information. They all use that information to build proteins from the same set of building blocks, known as amino acids.