Image credit: NASA.govThirty-three years ago Voyager space craft set its sights on the edge of the solar system. It’s feeling around to see where the edge really is, which is a boundary that sort of oscillates back and forth making it that much harder for the space craft to get a feel for it. However, scientists will be able to detect when its finally beyond the boundary of the sun. Did you know it takes 12.5 hours for a signal to get all the way out to the edge of the solar system? Also, just how big is the milky way? It’s the second largest spiral galaxy we know of and is 100,000 light years in diameter. But don’t get too close to the center because there is a super massive black hole you might want to avoid.[audio: st20100705.mp3]Ever wonder about the power of the moon? Check out this discussion at the Franklin Institute.