Astro Blog

By Sarah Stanley , Eos/AGU.  Excerpt: Spectacular aurorae dance and shimmer nearly continuously at Jupiter’s poles. ...Sometimes, Jupiter’s aurorae grow much brighter for hours or days at a time. ... clarifying the solar wind’s role  in any one brightening event would require taking simultaneous measurements of Jupiter’s magnetosphere and aurorae and their relationship with the solar wind—a difficult undertaking. ...NASA’s  Juno mission  has made such simultaneous measurements possible.  Giles et al.  used data... from two of Juno’s onboard instruments...as Juno neared Jupiter in its elliptical orbit on 6 December, the spacecraft was overtaken by the outer edge of the shrinking magnetosphere before later reentering it closer to Jupiter. ...Another of Juno’s instruments, its ultraviolet spectrograph, measured the aurora’s peak power at this time to be 12 terawatts—6 times its baseline power level. ...the researchers concluded that the powerful auroral d...

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 MICHAEL GRESHKO , Science.  Excerpt: Earth got its bell rung this past weekend, sucker-punched by the Sun itself in the biggest geomagnetic storm in more than 2 decades. The storm—triggered when the magnetic fields in blobs of plasma from the Sun collided with Earth’s magnetic field—not only yielded once-in-a-generation aurorae at latitudes as low as the Florida Keys, but also took scientists’ breath away with its power. ...This weekend’s fireworks began with Active Region 3664, a giant cluster of sunspots, more than 15 times wider than Earth, where the Sun’s magnetic field is highly concentrated. The magnetic field lines twisted and eventually snapped, causing the cluster to fling off a series of enormous, billion-ton blobs of plasma toward Earth, each embedded with strong magnetic fields. The detection of at least five of these expulsions, known as coronal mass ejections (CMEs), caused U.S. forecasters to  issue a “severe” G4 watch —its first since 2005—on 9 May, the day ...

By Angela Fritz, Elise Hammond and Chris Lau, CNN.  Excerpt: A series of  solar flares and coronal mass ejections  have created dazzling auroras that may be seen as far south as Alabama and Northern California — but could also disrupt communications on Earth over the weekend.... [See photos too.]  Full article at https://www.cnn.com/weather/live-news/geomagnetic-solar-storm-northern-lights-05-10-24/index.html . 

https://www.nytimes.com/2023/02/16/science/auroras-jupiter-moons.html By Robin George Andrews , The New York Times.  Excerpt: New research shows auroras can also be seen on the Galilean moons of Jupiter:  hypervolcanic Io ,  icy Europa , quirky Callisto and  gigantic Ganymede . ...other than  Ganymede , the big moons of Jupiter lack magnetic bubbles. Instead, their auroras owe their existence to Io. Its noxious atmosphere — partly supplied by the moon’s  epic volcanic eruptions  — regularly sheds into space. The castoffs mingle with sunlight and become electrically excited. Plenty gets captured by  Jupiter’s colossal magnetic bubble , but some of it slams back into Io’s atmosphere, or into the other three moons’ gassy sheaths. Those impacts are what ignite the moons’ auroral lights....