This artist's conception released February 6, 2013 courtesy of NASA shows a hypothetical planet with two moons orbiting in the habitable zone of a red dwarf star. (NASA/ D. Aguilar/Harvard-Smithsonian Center for Astrophysics)

Harvard scientists say "Earth-like" planets are "probably in our own backyard."

The researchers from the Harvard-Smithsonian Center for Astrophysics used data from NASA's Kepler telescope to calculate that 6% of red dwarf stars have habitable planets about the same size as Earth.

Red dwarfs are the common stars in the galaxy -- there are at least 75 billion -- which means the nearest Earth-like planet to Earth could be 13 light-years away.

"We thought we would have to search vast distances to find an Earth-like planet. Now we realize another Earth is probably in our own backyard, waiting to be spotted," said lead author and astronomer Courtney Dressing in a press release.

"We now know the rate of occurrence of habitable planets around the most common stars in our galaxy," said co-author David Charbonneau. "That rate implies that it will be significantly easier to search for life beyond the solar system than we previously thought."