Astronomy and physics instructor David Kriegler will discuss asteroids and comets at the next Omaha Science Café at 7 p.m., March 12 at the Slowdown, 729 N. 14th Street. Kriegler has been an instructor of astronomy and physics for the last 40 years at the University of Nebraska at Omaha, where he is the director of the Mallory Kountze Planetarium. Also, Kriegler has developed online courses in physics and astronomy and an astronomy lab which is part of UNO’s online curriculum for several degrees. Science Cafés involve a face-to-face conversation with a scientist about current science topics. They are open to everyone (21 and older), and take place in casual settings like pubs and coffeehouses. Each meeting is organized around an interesting topic of conversation. A scientist gives a brief presentation followed by a question and answer period. Pizza will be provided by The Nebraska Coalition for Lifesaving Cures for the first 50 people. For more information about Science Cafes, go to www.unmc.edu/sciencecafe.