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...
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...
It’s not fuzzy caterpillars or any small creatures interacting in a Petri dish. The strange growing and twisting creatures are not creatures at all. Today’s NASA APOD shows a time lapse view of a cluster of sunspots as they pass along the surface of the Sun during its rotation. The total time is about 12 hours for the sunspots to cross the solar surface, yet the video is shortened to a quick minute and a half. The amazing thing to notice is the amazing dance of the sunspots as they shift, twist, merge, separate, and interact with the granular convection cells...
The surface of the Sun is around 5500 degrees Celsius. It’s hot, and it’s a completely different state of matter than the solid, liquid, and gas states that we are used to. However, this is a pretty balmy temperature compared to the solar atmosphere, which is heated to over a million degrees. But how does it get so hot compared to the surface? We know the core of the Sun, where fusion happens, is where temperatures can reach 14 Million degrees, but how is that energy radiated outward? And more importantly, how does it bypass the solar surface and make...
