http://www.reuters.com/article/us-space-planets-idUSKBN19A2UU

Astronomers on Monday added 219 candidates to the growing list of planets beyond the solar system, 10 of which may be about the same size and temperature as Earth, boosting the chances for life.

Scientists found the planet candidates in a final batch of NASA’s Kepler Space Telescope observations of 200,000 sample stars in the constellation Cygnus.

The candidates include 10 newly discovered rocky worlds that are properly distanced from their parent stars for water, if it exists, to pool on their surfaces. Scientists believe liquid water is a key ingredient for life.

“An important question for us is, ‘Are we alone?’” Kepler program scientist Mario Perez said in a conference call with reporters. “Maybe Kepler today is telling us indirectly … that we are not alone.”

The National Aeronautics and Space Administration launched the Kepler telescope in 2009 to learn if Earth-like planets are common or rare. With the final analysis of Kepler data in hand, scientists said they will now work on answering that question, a key step in assessing the chance that life exists beyond Earth.

If intelligent life has a 1 in a billion chance of evolving around any given star, that is 100 intelligent species in our galaxy that have evolved or will evolve around the 100 billion stars currently in our galaxy…

Extending this to the observable universe (~10^23 stars- give or take a few 10′s of billions of trillions) that gives us 100 trillion intelligent lifeforms…