Astronomers announced on Wednesday that around 60 percent of the galaxy's most omnipresent stars, the red dwarfs, likely host planets smaller than Neptune and about six percent of these starts host Earth-sized planets. Red dwarfs make up about 75 percent of the stars closest to the sun.
Courtney Dressing, a graduate astronomer who led the study at the Harvard-Smithsonian Center for Astrophysics, told reporters, “The nearest Earth-like planet is expected to be about 13 light years away." She also said, "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."
An assistant professor of astronomy at the California Institute of Technology, John Johnson said that Courtney’s findings are "extraordinarily exciting." He also said, "What we need to do is take the next step in designing the next generation of instruments that will allow us to gather these small planets from the sky, study their properties in detail and provide us with an understanding of how Earth-size planets form," adding, "It will give us that grander galactic context and it puts us hot on the trail of finding life elsewhere in the galaxy. ... Keep in mind that all of these planets that we now know are out there, these are physical locations, places throughout the galaxy where life could have emerged."
To explain the energy emitted by the red dwarfs, David Charbonneau, a Harvard astronomer, said that if we picture the sun as a thousand-watt light bulb, these stars would be Christmas tree lights, emitting one or two watts of energy. So planets at the right distance to be of the same temperature as the Earth have to be tucked in close to these stars. He said, "What is so exciting about the announcement today is that it raises the real possibility of ... finding planets that are like the Earth ... but are actually much, much older, and actually seeing what that the consequence would be for a 10- or 11-billion-year-old Earth-like planet.”