By Elizabeth Landau, CNN
We still don't know if Earth, as a planet that currently harbors life, is alone in the universe. But scientists are actively searching for clues about other potential habitable worlds outside our solar system.
Astronomers are presenting their latest findings at the American Astronomical Society annual conference in Long Beach, California, this week. The word on the cosmic street is that Earth-sized planets are relatively common and that hundreds of new planet candidates have been identified.
"We have begun to truly map the planets in our galaxy akin to the way that early explorers mapped the Earth," said Sara Seager, professor of planetary science and physics at the Massachusetts Institute of Technology, who works with data from the NASA Kepler mission, which aims to identify planets outside of Earth's solar system.