Are we alone?
Human beings have been asking this questions for ages now.
Now, a radio signal from deep space offers the best chance yet to answer this question.
In February 2003, astronomers involved in the search for extraterrestrial intelligence (SETI) pointed a radio telescope in Arecibo, Puerto Rico, at around 200 sections of the sky, New Scientist magazine reported on Thursday.
The telescope had previously detected unexplained radio signals at least twice from each of these regions, and the astronomers were trying to reconfirm the findings.
The data has now been analysed and all the signals seem to have disappeared.
Except one, which has got stronger.
The magazine said that the signal, now seen on three occasions, could be generated by a previously unknown astronomical phenomenon, or even be a by-product from the telescope itself.
But it could also be a contact by intelligent aliens.
The signals were picked up through the SETI+home project, which uses programmes running as screensavers on millions of personal computers worldwide to sift through the huge amount of data picked up by the telescope.
Named SHGb02+14a, the signal, which seems to be coming from a point between the constellations Pisces and Aries, has a frequency of about 1420 megahertz.
It is the main frequency at which the universe's most common element, hydrogen, absorbs and emits energy, and which astronomers say is the most likely means by which aliens would advertise their presence.
"We are looking for something that screams out 'artificial'," the magazine quoted University of California, Berkeley, researcher Eric Korpela as saying.
