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.

In Brilliant Blunders: From Darwin to Einstein, astrophysicist Mario Livio explores the colossal errors committed by scientific greats, from chemist Linus Pauling's botched model of DNA, to Charles Darwin's failure to understand genetics--the very mechanism of natural selection.

Nobel Prize-winning psychologist Daniel Kahneman is the latest subject in our Desktop Diaries series, although he has no desk. Kahneman, professor emeritus at Princeton University, won the Nobel Prize in economic sciences in 2002 for his research with the late Amos Tversky on our sometimes irrational intuitions and how they affect decision-making.