When you look up at the night sky, what do you see?  A few stars, or a satellite, maybe even one of the seven other planets in our solar system?  But how many planets are there in all of outer space? We asked astronomer Mark Popinchalk to help us find the answer!

Got a question taking up space in your brain? Send it to us at BrainsOn.org/contact, and we’ll launch an investigation for the answer!