Astro Blog

By Hannah Richter , Science.  Excerpt: For decades, elementary students learned the same tale of the Solar System: first come rocky terrestrial planets such as Earth, followed by gas giants such as Jupiter and ice giants such as Neptune, with lovable Pluto bringing up the rear. ...the so-called ice giants likely contain very little ice. ...Uranus and Neptune were first called ice giants because they orbit past the Solar System’s so-called ice lines: the points beyond which water, ammonia, carbon monoxide, and other volatile molecules exist as solids rather than gases. If this region abounded with frozen water during the early Solar System, then Uranus and Neptune’s interiors might consist mostly of water, squeezed by the pressure of the planets’ gravity into a hot “supercritical” soup. ...researchers have come up with a smorgasbord of ideas about the interiors of our outermost planets. The newest, posted as a preprint last week and currently in review at The Astrophysical Journal ,...

By Robin George Andrews , The New York Times.  Excerpt: The vermilion, amethyst and jade ribbons of the northern and southern lights are some of Earth’s most distinctive features. But our planet doesn’t have a monopoly on auroras. Scientists have spied them throughout the solar system, ... Mars , Saturn,  Jupiter  ...some of Jupiter’s  fiery and icy moons ... Uranus , too. But auroras around our sun’s most distant planet, Neptune, have long eluded astronomers. That has changed with the powerful infrared instruments aboard the James Webb Space Telescope. In a study published on Wednesday in the journal  Nature Astronomy , scientists reveal unique auroras that spill over either side of Neptune’s equator, a contrast with the glowing gossamer seen arcing over other worlds’ poles..  Full article at https://www.nytimes.com/2025/03/26/science/neptune-aurora-nasa-webb-telescope.html . 

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. 

https://www.scientificamerican.com/article/the-best-of-jwsts-cosmic-portraits/ By Clara Moskowitz , Scientific American.  Excerpt: [Images Jupiter, Neptune and their rings as well as the phantom galaxy, M74.]

https://www.nasa.gov/feature/goddard/2022/new-webb-image-captures-clearest-view-of-neptune-s-rings-in-decades By NASA  Laura Betz   (Goddard Space Flight Center, Greenbelt, MD), Hannah Braun and Christine Pulliam (Space Telescope Science Institute, Baltimore, MD).  Excerpt: ...Webb’s extremely stable and precise image quality permits these very faint rings to be detected so close to Neptune. ...Compared to the gas giants, Jupiter and Saturn, Neptune is much richer in elements heavier than hydrogen and helium. This is readily apparent in Neptune’s signature blue appearance in  Hubble Space Telescope images  at visible wavelengths, caused by small amounts of gaseous methane. Webb’s  Near-Infrared Camera  (NIRCam) images objects in the near-infrared range from 0.6 to 5 microns, so Neptune does not appear blue to Webb. In fact, the methane gas so strongly absorbs red and infrared light that the planet is quite dark at these near-infrared wavelengths, excep...

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...

Source:   Deborah Kent, Physics Today Excerpt:  ... sensational news of Neptune’s observation ... at the Berlin Observatory just after midnight on 23 September 1846. The discovery was seen as a remarkable accomplishment of celestial mechanics. ...the planet had been mathematically predicted before it was observed. … In the summer of 1845, French scientist Urbain Jean Joseph LeVerrier also started to study the irregularities of the orbit of Uranus. … LeVerrier sent his request to Johann Galle at the Berlin Observatory. ...after less than an hour of observing, Galle reported “there is a star of the 8th magnitude in such and such a position, whereupon I immediately exclaimed: that star is not on the map!” www.physicstoday.org/resource/1/phtoad/v64/i12/p46_s1