 With the year wrapping up during this holiday week, I'd like to take a look back at what I think are some of the most exciting astronomy stories of the year. This is your space pod for December 25th, 2015. We're going to be taking a look back at what I consider to be the most exciting astronomical stories of the year. And they're going to be taking us from our cosmic backyard here in the solar system to the deepest fringes of the universe. So why wait? Let's get started. First up at number five, a single supernova with multiple surprises. Looking at galaxy cluster MACS J1149.6 plus 2223. With the Hubble Space Telescope, it may appear average to the normal observer. But to an astronomer, there's something funny going on. Not one supernova, but four supernovae happening in the same galaxy at the same time 9.5 billion light years away. It turns out this is actually light from a single supernova. And in a case just as weird as general relativity itself, the distribution of mass and its gravitational effect on the light has sent us that light on four separate paths, arriving at four distinctly different times. This discovery could aid us in nailing down an extremely precise measurement of the universe's rate of expansion and generate an accurate map of the distribution of both regular matter and dark matter along the path the light took. If this whole discovery isn't weird enough for you, a fifth path of light was predicted to arrive at the end of this year. And on December 11th, lo and behold, the fifth path of the supernova's light arrived here on Earth. Number four, water, water everywhere. What was thought to be a rare molecule is now becoming common place to find in the universe, water. In their own solar system, several new candidates for wet places received further investigation. In Celadus, one of Saturn's moons, is known to have liquid water geysers at its south pole. But after continued observation from NASA's Cassini spacecraft, it's now been confirmed that there's a subsurface liquid water ocean. In addition, Ganymede, one of Jupiter's moons, is also suspected to have a liquid water ocean beneath the crust of rock and ice. Looking at how Ganymede's auroral belts, interacted with Jupiter's massive magnetic field, helped researchers determine that about 150 kilometers below the surface, a 100 kilometer deep global ocean exists. Suddenly our solar system is teeming with possibilities of where life may exist right now. Number three, the surprise at Ceres. 2015 can be argued to be the year of the dwarf planet. NASA's Dawn mission became the first spacecraft to explore one. At its target, Ceres was generating excitement before the spacecraft's arrival. Imagery from the Hubble Space Telescope showed that a mysterious white spot was on the surface and persisted, meaning it was a real, actual feature. As Dawn's approach in January 2015 began to enhance our views of Ceres, that mystery of what the white spot was only grew bigger and bigger. Finally getting a good look, scientists were extremely puzzled as to what they were actually seeing. Was it a cryovolcano? Was it a fresh impact that excavated water ice below the surface? Was it salts from the outgassing of liquid water? It turns out what we're looking at is magnesium sulfate salts, similar to epsom salts here on the earth. With a crust rich with rock and ice, Ceres is an object in the asteroid belt that will continue to give up its mysteries as Dawn continues its mission through 2016. Number two, Mars is wet, very wet. The evidence is overwhelming. Water was once on early Mars, and it was there for a long period of time too. But just how much water was there? Scientists used infrared telescopes here on earth to take a look at Mars's atmosphere for the telltale signatures of water, H2O, and deuterium oxygen, a form of water known as heavy water. By comparing the ratios of these two kinds of water at different times during Mars' seasons, they were able to discover a huge surprise. Not only did Mars have water on the surface, it had an ocean in its northern hemisphere that held approximately 23 million cubic kilometers of water, an ocean roughly the size of the Atlantic. With more water, Mars was likely wetter for longer, meaning that Mars could have been habitable for longer as well. In addition, recurring slope lineae, a now confirmed phenomena, proved that during certain seasons in certain areas of Mars' surface, extremely salty liquid water flows. It seems Mars is a little more like home than we originally imagined. And finally, the biggest story of the year. Number one, Pluto, strange, small, and striking. Look, if anyone told you that they knew Pluto would turn out as complex that has shown itself to be, then you have my permission to call them a liar, because no one expected this. In 1930, we had a dot on a photographic plate. In 1995, the Hubble Space Telescope gave us a few pixels. In 2003, Hubble again gave us those few pixels, but in color. And finally, this year, on July 14th, 2015, NASA's New Horizons probe gave us Pluto in its full glory. The surface topography is so varied, scientists working on New Horizons have dubbed it chaos terrain, with tall mountains set against vast, smooth plains, where surfaces billions of years old are snuggled up directly to surfaces a hundred million years old. It truly makes very little sense. Pluto is so small that the internal heat that would drive its active geology should have dissipated a long time ago. But looking at its surface would tell you a different story altogether. The images we're getting back from New Horizons will change planetary geology forever. With a width of 2,370 kilometers, Pluto has now been officially confirmed as the largest object beyond Neptune's orbit, knocking off Eris as the top in size. Its atmosphere extends out 130 kilometers above the surface, well above what we would have expected for a dead world. And Pluto's moon, Sharon, is also as equally chaotic in its terrain, the most noticeable being a massive canyon across its face. Nyx, Hydra, Styx, and Kerberos also add to the mystery of the plutonium system. Faced with all of these questions, answers may still be on New Horizons, as being over 5 billion kilometers away and only running on several hundred watts of power means that it can only transmit data at a rate of about one kilobyte per second. This means we'll have to wait until late 2016 for all the scientific data to be downlaked. Oh, what further mysteries await us? Only time and data will tell. Thanks for watching the Space Pod. I'm Jared Head. What are some of your favorite space science stories of the year? Tell me in the comments below. And don't forget to like and subscribe to us on tomorrow. In addition, we're continuing our Space Pod Patreon campaign, and things are moving nicely. We've actually reached our first milestone, $250 a month, which means that you're going to be getting two Space Pods per month. It will be really amazing to see us reach our next milestone, $500 per month by the beginning of 2016. A $500 per month will make four Space Pods per month. And as of the making this pod, we're only $166 away from that milestone. In 2016, Space Pod Patreon contributors will have their name seen in every single Space Pod, much like what we have with our live Saturday shows of tomorrow. In addition, Space Pod Patreon contributors will also have access to exclusive Space Pod content. With approximately 10 to 15 hours of research, writing, shooting, and editing that goes into every Space Pod, any little contribution helps. And if you'd like to help us to continue to make these Space Pods, head on over to Patreon.com slash Space Pod. This is my final Space Pod of 2015. And I can't wait to see what tomorrow brings in 2016. So until the next Space Pod, keep exploring. We'll be able to do it. This is, if it does, it's going to be amazing, so. Oh my god, they did it. They, they f***ing did it. I can't believe. Oh, I'll forget it, forget it. I'm done. I have no career. I have no career. No career.