And I'm Flora Lichtman. In 2007, thousands of people in Mexico took to the streets, protesting the price of tortillas. In three months, the price of corn had gone up 400 percent. Why? According to my first guest, it all started with a spike in oil prices triggered by Hurricane Katrina. That led to increased demand for ethanol, and U.S. farmers who grow a lot of the corn that Mexicans eat planted less corn for eating and more corn to make ethanol.
A flurry of extreme weather events, including wildfires, heat waves and droughts may have convinced more Americans that the planet is warming. A poll by the Brookings Institute found that 62 percent of Americans now believe in global warming, and nearly half of them have cited warmer temperatures or change in weather patterns as the reason for their belief.
The universe is being pushed apart at a faster and faster rate. And the culprit? Dark energy. Astrophysicist Adam Riess shared the 2011 Nobel Prize in Physics for that discovery, and now's your chance to ask him about it--or anything else you've been wondering about the cosmos.