Aliens may know where we exist

Aliens may know where we exist

According to reports, aliens probably know about our existence. John Grunsfeld, a former NASA astronaut, told the Astrobiology Science Conference in Chicago US that aliens may know about humans from the changes they made to Earth's environment.

Most of the scientific community considers that alien life has to do with tiny single celled microbes that could not be seen with the naked eye.

According to Grunsfeld, who is now an associate administrator for NASA's Science Mission Directorate, "If there is life out there, intelligent life, they'll know we're here. We put atmospheric signatures that guarantee someone with a large telescope 20 light years away could detect us".

He gave these statements after a team of Scottish scientists found evidence of methane gas on Mars that indicate existence of life on Mars.

In April, NASA's chief scientist Ellen Stofan had said that the first signals of alien life could appear by 2025. And it could reveal more solid evidence of alien life in next 20 to 30 years.

Stofan predicted that mankind is probably not alone in the universe. She talked about water in the universe at a panel discussion and said that alien life won't be 'little green men'.

According to Jim Green, director of planetary science at NASA, a recent study of the Martian atmosphere showed that 50% of the planet's northern hemisphere was once having oceans a mile deep. It was found in the same study that water had been present on Mars for up to 1.2 billion year.