In 1584, Dominican priest Giordano Bruno had said that nature of all planetary worlds was similar to earth as they all had very high odds of having animals and inhabitants. The Catholic Church seized the fate of Bruno after a seven-year trial; he was declared a heretic and killed on February 17, 1600.

His hypothesis was published after 400 years and NASA also managed to gather funds in 1984 to go ahead with the mission of searching for extraterrestrial intelligence (SETI) by sending radio signals up to 1,000 light-years away and wait for the response they might get from aliens.

Russian billionaire Yuri Milner with the support from British physicist Stephen Hawking has now offered his support to the mission through $US100 million funding over the next decade to strengthen efforts of SETI researchers to come up with robust evidence for alien existence.

Experts say that ancient religions point towards the cosmos as a home to a pantheon of gods. German-born Cardinal Nicholas of Cusa mentioned in 'On Learned Ignorance', published in 1440, that the Moon and the Sun could have aliens.

Percival Lowell, who studied mathematics at Harvard University before turning his attention to astronomy, built the Lowell Observatory at Flagstaff, Arizona, to study Mars in 1894. He thought that intelligent Martians created canals on the Red Planet to carry water from polar caps to equatorial -regions.

The hunt is still on to find evidence for intelligent life living outside earth, but we only have to wait and watch till the efforts start paying off.