Astro Blog

By Jonathan O’Callaghan , The New York Times.  Excerpt: We might finally understand what’s going on inside Uranus and Neptune, and the answer is pretty surprising: They may each contain an ocean of water. ...The idea about the two ice giant planets — so-called because of the freezing conditions in which they formed — was put forward by Burkhard Militzer, a planetary scientist from the University of California, Berkeley, and was  published Monday in the Proceedings of the National Academy of Sciences . It could explain the strange magnetic fields of both worlds, which are unlike any other in the solar system....  Full article at https://www.nytimes.com/2024/11/25/science/uranus-neptune-oceans.html .  See also UC Berkeley News A clue to what lies beneath the bland surfaces of Uranus and Neptune , By Robert Sanders. 

By  Jamie M. Jasinsk  et al, Nature Astronomy. Summary: A human spacecraft has only gotten close to Uranus once—in 1986, when Voyager 2 drifted past the distant planet. That flyby indicated that   Uranus was weird in several ways , which astronomers have spent decades trying to explain. Now, a new analysis in   Nature Astronomy   suggests the probe   just happened to arrive there on an off day . Voyager 2’s data indicated that Uranus had an “unusually oblique and off-centered magnetic field” with inexplicably intense electron radiation belts and a severely plasma-depleted magnetosphere,” the team behind the new work writes. But by mining old data from the mission, the scientists found evidence for a super strong solar wind that likely squished the magnetosphere just prior to the probe’s readings. This would have pushed any plasma too close to the planet to detect, and filled the radiation belts with high-energy particles. https://www.nature.com/articles/s41...

https://skyandtelescope.org/astronomy-news/four-of-uranuss-moons-might-contain-briny-oceans/ By Emily Lakdawala, Sky & Telescope.  Excerpt: A  new paper re-analyzing Voyager observations  suggests that four of Uranus’ five icy satellites also host oceans: Ariel, Umbriel, Titania, and Oberon. (Only small Miranda, intermediate in size between Saturn’s Mimas and Enceladus, appears not to.) The oceans are desperately thin: less than 30 kilometers (20 miles) thick inside Ariel and Umbriel (both of which are about 1,000 kilometers across, similar in size to Saturn’s Tethys and Dione), and less than 50 kilometers thick within Titania and Oberon (which are larger at about 1,500 kilometers, similar to Saturn’s Rhea and Iapetus). If the oceans exist, they would be left over from much larger liquid layers that formed when the moons first formed. ...They’d be extremely briny, hyper-concentrated with whatever dissolved materials helped to lower the temperature at which water would...

https://eos.org/research-spotlights/a-unified-atmospheric-model-for-uranus-and-neptune By  Morgan Rehnberg , Eos/AGU.  Excerpt:  In a new model, three substantial atmospheric layers appear consistent between the ice giants.  The ice giants, Uranus and Neptune, are the least understood planets in the solar system. They remain the only worlds that an orbital spacecraft has not visited. Our limited understanding of them derives largely from the flyby of NASA’s  Voyager 2  probe and subsequent observations with the  Hubble Space Telescope . Yet the ice giants may be most representative of the extrasolar planets in our local vicinity. Why these planets appear so different in color despite having very similar physical properties, including vertical temperature profile and atmospheric composition, is a mystery. Past investigations have attributed Neptune’s deeper blue largely to excess absorption in the red and near infrared from atmospheric methane. ... Irwi...