Alien Planets

n 1995, astronomers discovered there are planets that revolve around stars other than our sun. These “extra” or “exo-solar” planets have not actually been seen or photographed but scientists are able to measure their gravity, and, just recently, two of the planets’ light, as proof they exist. Astrophysicist Neil deGrasse Tyson heads New York’s Hayden Planetarium and he joins Living on Earth host Steve Curwood to talk about what lies beyond our solar system.