Talk of the Nation

Generations of physicists have claimed that time is an illusion. But not all agree. In his book Time Reborn: From the Crisis in Physics to the Future of the Universe, theoretical physicist Lee Smolin argues that time exists--and he says time is key to understanding the evolution of the universe.

Scientists reported this week in the journal Cell that they had used somatic cell nuclear transfer techniques to create a source of embryonic stem cells from the skin cells of a patient. George Daley, director of the stem cell transplantation program at Boston Children's Hospital, and Josephine Johnston of the Hastings Center discuss the research.

A report from the UN Food and Agriculture Organization says insects offer a huge potential for improving the world's food security. Peter Menzel, co-author of Man Eating Bugs, describes some insect-based cuisine and the western aversion to creepy-crawly snacks.

As the death toll in Syria climbs and critics blast the Obama administration for not taking more decisive action, former ambassador Christopher Hill points instead to a failure of diplomacy in an op-ed in the New York Times. Hill talks about what the U.S. faces in facilitating talks between the regime and Syrian rebels.

Days after the marathon bombing, officials established the One Fund for Boston to assist victims and their families. Attorney Ken Feinberg, who managed similar funds after Sept. 11 and Virginia Tech and is managing this fund, says there's no easy way to decide who gets how much of the $30 million that's been donated.