Talk of the Nation

Scientists say X-ray data collected by the European Space Agency's XMM-Newton spacecraft show evidence of a new type of black hole in a galaxy about 290 million light years from Earth. Astronomer Sean Farrell explains what the discovery might tell us about galaxy evolution. ()  

In case you forgot to pick up some sparklers for the holiday weekend, don't despair. Ira Flatow and a team of backyard science experts explain how to (safely) make firecrackers, smoke bombs and even an Oreo-fueled rocket, all while learning some basic scientific principles. ()  

Why do some fireworks shoot golden flaming balls while others produce green sparks? It's just chemistry. Bassam Shakhashiri, chemistry professor at the University of Wisconsin-Madison, explains the science of fireworks. ()  

Reporting in Nature Geoscience, two coastal scientists write that rising sea levels, combined with slow Mississippi Delta growth, could drown the Louisiana coast by 2100. Delta expert Ivor van Heerden, who is not involved with the research, discusses the findings. ()  

Deep-sea voyager Robert Ballard has discovered everything from 10-foot-tall tube worms to the Titanic on his ocean expeditions around the world. Ballard discusses his underwater finds and how new robotic technology allows scientists to explore the sea from ashore. ()