Headline image caption & credit: Our solar system may have once had at least one additional planet. Image Credit: NASA via unexplained-mysteries: Scientists have found evidence to suggest that another world once existed between Uranus and Saturn. While much of the effort involved in tracking down the rumored 'Planet Nine' has focused on exploring the outer reaches of our solar system, some researchers believe that there may in fact have once been a sizable planet much closer to home, somewhere between the orbits of Uranus and Saturn. This ancient, icy world was likely ejected from the solar system billions of years ago. To determine this, scientists created thousands of simulations to rewind the clock and recreate the orbits of the planets - and in particular the gas giants - to examine how they evolved over time. "We now know that there are thousands of planetary systems in our Milky Way galaxy alone," said study lead author Matt Clement from the Carnegie Institution for Science. "But