Real-life Sci-Fi World 14: A horseshoe planetary system

One star. Two planets share an orbit, with one following a horseshoe-shaped path around the other. Boom!

Is Pluto a mega-comet?

Short answer: Well sort of, but it’s more useful to think of it as being built from the same stuff as comets. Like an Uncle of the comets. Read on for an explanation. Earlier this week my wife mentioned a headline she saw.  “Pluto is a giant comet?  Whoa!” It was all over the place:…