(CNN) -- Since the time of Nicolaus Copernicus five centuries ago, people have wondered whether there are other planets like Earth in the universe. Today scientists are closer than ever to an answer -- and it appears to be that the Milky Way galaxy is rich in Earth-sized planets, according to astronomer Dimitar Sasselov.

Drawing on new findings from a NASA telescope, he told the TED Global conference in Oxford, England earlier this month that nearly 150 Earth-sized planets have been detected so far. He estimated that the overall number of planets in the galaxy with "similar conditions to the conditions that we experience here on Earth is pretty staggering. It's about 100 million such planets."

Read more here: http://www.cnn.com/2010/OPINION/07/27/sasselov.earth.planets/index.html?hpt=T2