Extraterrestrial research experts have said that now is the time to contact intelligent life on alien worlds.

Leading figures behind the Search for Extraterrestrial Intelligence (Seti), which has been using radio telescope to detect unnatural signals from space in search of intelligent extraterrestrial life, proposed an active form of alien life search dubbed Messages to Extraterrestrial Intelligence (Meti).

Meti signals will be targeted in parts of the galaxy where life may exist in Earth-like planets based on the increasing number of exoplanets identified by the Kepler space telescope.

Douglas Vakoch, a proponent of sending signals to alien life, said that there are now natural targets for transmission projects given the recent detection of Earth-like planets in the so-called habitable zones.

At the annual meeting of the American Association for the Advancement of Science in San Jose, Seti director Seth Shostak told the attendees that this moment is an opportune time for humans to bolster efforts to search for other beings on other planets.

"Some of us at the institute are interested in 'active Seti,' not just listening but broadcasting something to some nearby stars because maybe there is some chance that if you wake somebody up you'll get a response," Shostak said.

There are concerns, however, that actively reaching out to extraterrestrial life could potentially lead to our planet's devastation.

Renowned cosmologist Stephen Hawking warned in 2010 of the potential consequences should alien civilizations get notified of the presence of our planet. They may be attracted to Earth and may have the technology required to travel to our planet and exploit its resources.

The scientist likened the event of aliens visiting Earth to when Columbus landed in America, which did not turn out favorable to the Native Americans.

Science fiction writer David Brin, who opposes the proposal to send the signals, said that the odds of making contact with alien life is very low but it involves extremely high risks that require careful consideration before somebody sends a signal to worlds potentially inhabited by alien life. He said that shouting into the cosmos without the right risk assessment could place the future generations of the Earth at risk.

Radio astronomer Frank Drake described active Seti to be a waste of time at the moment.

"It's like somebody trying to send an email to somebody whose email address they don't know, and whose name they don't know," Drake said.