New York, June 18 (IANS) Still waiting to hear from aliens and getting excited about the UFO sightings? Well, according to astronomers, extra-terrestrials are not likely to call the Earth for the next 1,500 years.

The team from Cornell University made this assumption by deconstructing the Fermi paradox and paring it with the mediocrity principle into a fresh equation.

The Fermi paradox says billions of Earth-like planets exist in our galaxy yet no aliens have contacted or visited us. 

Thus the paradox: the cosmos teems with possibility. 

The mediocrity principle is the idea that because we are not in any special location in the universe, we should not be anything special in the universe, physics.org reported.

“We haven't heard from aliens yet, as space is a big place. But that doesn't mean no one is out there," said Cornell student Evan Solomonides who presented the study at the American Astronomical Society's meeting in San Diego, California, recently.

Hunting for extra-terrestrials means sending out signals like television broadcasts, for example. 

As Earth's electronic ambassador, TV and radio signals are sent into space as a by-product of broadcast. 

Earth's broadcast signals have reached every star within about 80 light years from the Sun - about 8,531 stars and 3,555 Earthlike planets as our Milky Way galaxy alone contains 200 billion stars.

"Even our mundane, typical spiral galaxy - not exceptionally large compared to other galaxies - is vast beyond imagination," Solomonides added. 

"Those numbers are what make the Fermi Paradox so counterintuitive. We have reached so many stars and planets, surely we should have reached somebody by now, and in turn been reached … this demonstrates why we appear to be alone,” he added.

Combining the equations for the Fermi paradox and the mediocrity principle, the authors suggests Earth might hear from an alien civilisation when approximately half of the Milky Way Galaxy has been signalled in about 1,500 years.

Yervant Terzian, Cornell's Tisch Distinguished University Professor of Astronomy, is the co-author of the paper.​