A U.S. space telescope set for launch in 2014 could reveal the presence of oceans on planets outside the solar system, scientists say.

Detecting water on Earth-like planets would offer the tantalizing prospect they could sustain life, and scientists hope the reflection of light, or "glint", from mirror-like ocean surfaces could be picked up by the upcoming generation of space telescopes, the BBC reported Thursday.

Tyler Robinson at the University of Washington in Seattle said he thinks the new technique could be used in the search for the "holy grail" for exoplanet astronomy, a possible sister planet to Earth.

"We're focusing on a class of extra-solar planets yet to be detected, things comparable in size and composition to the Earth and similar distances from their central star as the Earth is from the Sun," he said. "The goal is to find something Earth-like in almost every sense of the world so we can even prove it has liquid oceans on its surface."

Robinson said he hopes "glint" -- the effect seen when light is reflected from an ocean's surface -- may reveal the presence of Earth-like planets beyond our cosmic neighborhood.

Presently, clues like tell-tale glint spots are vital to finding Earth-like planets because astronomers are decades away from being able to directly image the surface of these alien worlds 20 or 30 light-years away.