The search for exoplanets and alien life is generating a lot of hype but the study needs patience and refinement, a U.S. review of exoplanet research suggests.

Review author Adam Burrows, a Princeton University professor of astrophysical sciences, says despite many trumpeted results, few "hard facts" about exoplanets -- planets orbiting distant stars outside our solar system -- have been collected since the first one was detected in 1992, and most of these data are of "marginal utility."

That's because the current dominant methods for studying exoplanets and their atmospheres are not intended for objects as distant, dim and complex as planets trillions of miles from Earth but were instead designed to study much closer or brighter objects, such as planets in Earth's solar system and stars, he wrote in the Proceedings of the National Academy of Sciences.

As with any relatively new field of study, fully understanding exoplanets will require a lot of time, resources and patience, Burrows said in a Princeton release Tuesday.

"Exoplanet research is in a period of productive fermentation that implies we're doing something new that will indeed mature," he said. "Our observations just aren't yet of a quality that is good enough to draw the conclusions we want to draw."

"There's a lot of hype in this subject, a lot of irrational exuberance. Popular media have characterized our understanding as better than it actually is," he said. "They've been able to generate excitement that creates a positive connection between the astrophysics community and the public at large, but it's important not to hype conclusions too much at this point."