When you start to think about the most massive and extreme ‘stuff’ in the universe, you inevitably go to Dark Matter and Dark Energy. They exist as opposites, one with incredible gravity holding the universe together, and the other a mysterious vacuum energy tearing it apart. Studying this cosmic tug of war gives astronomers a chance to determine the past and future of the entire universe. To study the immense scale of these two quantities, the Baryon Oscillation Spectroscopic Survey (BOSS) program of the Sloan Digital Sky Survey-III (SDSS) constructed a 3D map of the sky, amounting to a volume...
At this stage of our understanding of the planet Mars, we have seen salty water flowing (recurring slope lineae), found evidence of ancient riverbeds, and seen seasonal changes in the polar caps. But an important question is how does water behave on Mars? A bit of science here on Earth gives some insight. Water at sea level on Earth boils at 100 degrees Celsius, which actually defined the Celsius scale. But as pressure changes, liquids boil at different temperatures. As the atmosphere gets thinner, the boiling temperature of water decreases. On Mars, with it’s extremely thin atmosphere, this means that water...
One of the most surprising and intriguing finds during the decade-long Cassini mission has been the discovery of geysers on the Moon Enceladus. Originally spotted in 2005, scientists have spent the last decade trying to understand how they work. And now they finally have a working model. How does an eruption on a frigid Moon last so long? Eruptions on Earth are not long-lived, and if they are, they are very spread out. For Enceladus to have a ton of localized geysers in the South polar region, you need some pretty specific scenarios. Aside from the fact that a constant stream of material could clog...
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...
