Less than two decades ago, there were exactly zero known planets orbiting sunlike stars in our Milky Way galaxy. Astronomers back then were engaged in a powerful struggle to seek out exoplanets, and they succeeded, so that today there are 861 confirmed exoplanets, according to exoplanet.eu on March 25, 2013. In the past year, astronomers have begun tossing around the word billion to describe how many planets might orbit Milky Way stars. Today (April 3, 2013), astronomers at The University of Auckland in New Zealand announced their new method for finding exoplanets. They say they anticipate 100 billion planets similar to our Earth, orbiting stars in the Milky Way. Their work will appear in the journal Monthly Notices of the Royal Astronomical Society.

Lead author of the New Zealand planet search – Dr. Phil Yock from the University of Auckland’s Department of Physics – said his team’s strategy is to use a gravitational microlensing technique. Yock said his team will use a combination of data from microlensing and NASA’s Kepler space telescope.

The Kepler space telescope, by the way, has single-handedly found 105 exoplanets and an astounding 2,740 planet candidates orbiting 2,036 stars (as of January 7, 2013). Yock said:

    Kepler finds Earth-sized planets that are quite close to parent stars, and it estimates that there are 17 billion such planets in the Milky Way. These planets are generally hotter than Earth, although some could be of a similar temperature (and therefore habitable) if they’re orbiting a cool star called a red dwarf.

Read more at http://earthsky.org