Despite being ingloriously stripped of "planet" status a few years ago (with Dr. Neil deGrasse Tyson admitting to "driving the getaway car"), Pluto is large enough to have several moons orbiting around it — and scientists have just discovered another, with the help of the venerable Hubble telescope. Pluto's fifth moon, currently known as S/2012 (134340) 1, was first photographed by Hubble on June 26th, with a total of nine separate sets of images captured over the last few weeks confirming its existence. Scientists expressed a bit of surprise that such a tiny dwarf planet can have such a complex system of satellites; the current theory is that Pluto collied with another large object billions of years ago, with its moons being a result of that collision.
Given the relatively size of Pluto, its new moon isn't terribly large in the grand scheme of things — it's believed to be irregularly shaped and between six and 15 miles across. While not quite as dramatic a discovery as the Hubble telescope made a few months ago, it's still exciting to discover more details about our solar system.