Astro Blog

By Davide Sulcanese ,  Giuseppe Mitri  &  Marco Mastrogiuseppe , Nature Astronomy.  Abstract: The surface of Venus has undergone substantial alterations due to volcanic activity throughout its geological history, and some volcanic features suggest that this activity persisted until as recently as 2.5 million years ago. Recent evidence of changes in the surface morphology of a volcanic vent has been interpreted as a potential indication of ongoing volcanic activity. To investigate more widespread alterations that have occurred over time in the planet’s surface morphology, we compared radar images of the same regions observed from 1990 to 1992 with the Magellan spacecraft. We found ...evidence of new lava flows related to volcanic activities that took place during the Magellan spacecraft’s mapping mission with its synthetic-aperture radar. This study provides further evidence in support of a currently geologically active Venus.  Full article at https://www.nat...

By Rachel Fritts , Eos/AGU.  Excerpt: The giant impact that formed the Moon may also have led to extrastrong mantle plumes that enabled the first subduction event, kick-starting Earth’s unique system of sliding plates. In a new study,  Yuan et al.  find evidence tracing the first subduction event to the same impact that created our Moon. ...Yuan’s team explored postimpact mantle convection using both 2D and 3D thermomechanical modeling. They found that the increase in temperature at the core-mantle boundary after the giant impact could have led, over time, to strong  mantle plumes —phenomena still seen today that can sometimes lead to volcanic activity far from plate boundaries....  Full article at https://eos.org/research-spotlights/earths-subduction-may-have-been-triggered-by-the-same-event-that-formed-the-moon . 

By Katherine Kornei , Eos/AGU. Excerpt: Using data from the Cassini spacecraft, researchers studying one of the rings recently uncovered gaps just a few tens of meters wide that they believe surround unseen mini moonlets. ...In addition to capturing  more than 450,000 images  of the Saturnian system, the spacecraft inadvertently tracked distant stars poking through Saturn’s rings. ...The researchers spotted dozens of places in Saturn’s C ring— one of its innermost rings —that appeared to be 100% transparent. ...Their elongated geometry was a tip-off to their potential identity—similarly shaped structures, albeit much larger, have been  spotted in the outer regions of Saturn’s A ring . Known as propellers [resembling airplane propellers], those features are big enough to show up in Cassini imagery rather than just occultation data, Jerousek said. ...Scientists believe that propellers exist because of unseen moonlets measuring, at most, several hundred meters in d...

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 . 

By JONATHAN O’CALLAGHAN , Science.  Excerpt: With surface temperatures hot enough to melt lead, Venus today is a veritable hellhole, despite being similar in size to Earth and orbiting in the habitable zone of the Sun. Yet studies suggest the planet may have once hosted oceans and even conditions suitable for life. Explaining how all that water disappeared has been a problem. A study  published today  in Nature offers a solution, identifying a new water-loss mechanism operating high in Venus’s atmosphere that could have doubled the rate of water loss. Speedier drying could have allowed oceans to exist until later in Venus’s history—implying the planet might have been habitable for longer. ...At 96% carbon dioxide, its atmosphere traps so much heat that surface temperatures reach more than 450°C. Yet spacecraft and telescopes have seen faint hints of water vapor in the atmosphere, and in the late 1970s, NASA’s Pioneer Venus orbiter detected a sign of long-vanishe...