Nasa announces press conference on 'discovery beyond our solar system'

Nasa will hold a press conference on Wednesday to present a "discovery beyond our solar system," leading to speculation that the announcement will involve planets capable of sustaining life.

The agency has offered no details on the upcoming presentation other than that it will involve "exoplanets".

Astronomers have been studying such planets, which orbit stars other than the sun, for clues as to whether, and where, life could exist beyond the earth.

Nasa has analysed dozens of planets that orbit sun-like stars at similar distances as the earth to the sun looking for signs that life may be possible there.

The first earth-like planet to be discovered was, Kepler-186f, a rocky planet that lies within the so-called "habitable zone" and is similar in size to earth. The Kepler space telescope has now located many more such planets.

At a press conference earlier this year Nasa announced the discoveries of 1,284 new planets, nine of which were in the "habitable zone". 

“One of the great questions of all time is whether we are alone in the universe," Paul Hertz, director of the Astrophysics Division at Nasa's headquarters in Washington, said at the time.

“We live in a time when humanity can answer this question scientifically. And the first sign of answering this question is looking at exoplanets," he said.

The US space agency has now identified 3,449 exoplanets in 2,577 solar systems. Among those planets, 348 are considered earth-like.

Wednesday's press conference will take place at 6 pm GMT (1 pm EST) on Wednesday and will be streamed live online: http://www.nasa.gov/nasatv