May 16, 2013 The news that scientists have successfully cloned a human embryo seems almost certain to rekindle a political fight that has raged, on and off, since the creation of Dolly the sheep. It's a fight that has, over the past decade and a half, produced a lot of heat and light and not a lot of policy.
May 16, 2013 Scientists have discovered water that was sealed in Canadian bedrock for nearly half of Earth's history. It may contain the descendants of ancient microbes. The discovery could give scientists new insights into early life on Earth and inform the search for life on other planets.
May 16, 2013 U.S. reconstruction teams have spent a decade building roads, bridges and other pieces of infrastructure that are badly needed in Afghanistan. But now the international effort is winding down, and it's not clear how much the Afghans will be able to do on their own.