One of the first things you hear when learning about the states of matter is about good old H2O: Steam, Water, Ice. Naturally you are asked “Why does Ice float?” The answer is a simple matter of density, frozen water is less dense because water expands when it freezes. You can do a bit of an experiment by filling a balloon with water. Paint the balloon and put it in the freezer. When it freezes the water will expand, and so will the rubbery balloon, but the dried paint will crack at weak points. This is exactly the same thing...
Since 2004, the Cassini spacecraft has been orbiting Saturn, giving us unprecedented views of the rings and Moons, and sending back data that has helped us to understand the dynamic nature of the Saturnian system. The flexibility of such a craft allows for new science goals to be determined in an ongoing basis, since new discoveries often lead to new questions and new areas to focus our resources on. Yesterday, October 28th, Cassini focused its resources on the geysers of Enceladus, flying lower than ever before over the surface of the icy moon, in an attempt to sample some of...
The mysteries of the Occator crater on Ceres have continued to puzzle astronomers and the public, even as we have seen increasing resolution in recent photos. The latest photos show a resolution of 140 meters per pixel and reveal striking details, though the jury is still out on what exactly the bright material is and where it came from. It seems incredibly likely that the bright spots are ices of some sort, maybe even water ice, since Ceres is a water-rich body, and may have more water than Earth! One hypothesis is that Ceres has a subsurface layer of water,...
When the Rosetta spacecraft entered orbit around comet 67P/Churyumov-Gerasimenko, first images captured deep circular depressions among the other surface features. Now that the orbiter has taken significant observations of the comet’s surface, the science team has concluded that these depressions are actually sinkholes that form by the same processes that form sinkholes 500 Million kilometers away here on Earth. Sinkholes on Earth form when subsurface material is eroded away. Though not initially visible on the surface, the material falls deep underground leaving a circular cavern. Once enough material has eroded away, the top of the cavern collapses, leaving a large...
