According to scientists, a newly-discovered planet is the most like Earth ever found. Astronomers sifted through 11 years of data recording subtle shifts caused by planets orbiting the star Gliese 581. They were able to find two new planets around the star, one of which is in a so-called 'habitable zone.'
■Class discussion: If this does turn out to be our sister planet, what would that mean to you? Could we go there for a visit? Slate points out that "Current space shuttles don't go much faster than 17,500 miles per hour. At that pace, it would take 766,000 years to get to Gliese 581 g -- that's more than three times longer than homo sapiens have been around." So why should we get excited about the possibility of life on a planet so far away?