Uploaded February 2014 | Updated September 2026, 2 days ago
http://www.astropage.eu/index_news.php?id=1390 Cassini gelingt eine 360-Grad-Ansicht der Polarlichter auf Saturn
Ultraviolet and infrared images from NASA's Cassini spacecraft and Hubble Space Telescope show active and quiet auroras at Saturn's north and south poles. Saturn's auroras glow when energetic electrons dive into the planet's atmosphere and collide with hydrogen molecules. Sometimes a blast of fast solar wind, composed of mostly electrons and protons, creates an active aurora at Saturn, as occurred on April 5 and May 20, 2013. The first set of images, as seen in the ultraviolet part of the spectrum by Hubble, shows an active aurora dancing around Saturn's north pole on April 5. The movie then shows a relatively quiet time between April 19 to 22 and between May 18 and 19. The aurora flares up again in Hubble images from May 20. This version, shown in false-color, has been processed to show the auroras more clearly. A second set of ultraviolet images shows a closer view of an active north polar aurora in white. This set comes from Cassini ultraviolet imaging spectrograph observations on May 20 and 21. The last set of images, in the infrared, shows a quiet southern aurora (in green) in observations from Cassini's visual and infrared mapping spectrometer on May 17. Saturn's inner heat glows in red, with dark areas showing where high clouds block the heat.
Image credit: NASA/JPL-Caltech/University of Colorado/Central Arizona College and NASA/ESA/University of Leicester and NASA/JPL-Caltech/University of Arizona/Lancaster University
http://www.astropage.eu/index_news.php?id=1390 Cassini gelingt eine 360-Grad-Ansicht der Polarlichter auf Saturn
Ultraviolet and infrared images from NASA's Cassini spacecraft and Hubble Space Telescope show active and quiet auroras at Saturn's north and south poles. Saturn's auroras glow when energetic electrons dive into the planet's atmosphere and collide with hydrogen molecules. Sometimes a blast of fast solar wind, composed of mostly electrons and protons, creates an active aurora at Saturn, as occurred on April 5 and May 20, 2013. The first set of images, as seen in the ultraviolet part of the spectrum by Hubble, shows an active aurora dancing around Saturn's north pole on April 5. The movie then shows a relatively quiet time between April 19 to 22 and between May 18 and 19. The aurora flares up again in Hubble images from May 20. This version, shown in false-color, has been processed to show the auroras more clearly. A second set of ultraviolet images shows a closer view of an active north polar aurora in white. This set comes from Cassini ultraviolet imaging spectrograph observations on May 20 and 21. The last set of images, in the infrared, shows a quiet southern aurora (in green) in observations from Cassini's visual and infrared mapping spectrometer on May 17. Saturn's inner heat glows in red, with dark areas showing where high clouds block the heat.
Image credit: NASA/JPL-Caltech/University of Colorado/Central Arizona College and NASA/ESA/University of Leicester and NASA/JPL-Caltech/University of Arizona/Lancaster University




![XJ1500+0154 Animations
Every so often, an object will pass too close to a black hole and be ripped apart by its intense gravitational forces. As the object, such as a star, approaches the danger zone of the black hole, its stellar debris is flung outward at high speeds, while the stars material falls towards the black hole. This in-falling material becomes hotter and hotter until it generates a signature outburst of X-rays. Astronomers call these tidal disruption events, or TDEs, and they can be used to better understand how black holes grow and affect their environments.
While astronomers have seen multiple examples of TDEs in recent years, a new discovery stands out among the rest. Using data from three X-ray telescopes: Chandra, Swift, and XMM-Newton, researchers have found a TDE that has lasted about ten years, much longer than other events. What could cause this decade-long meal by the black hole? There are a couple of possibilities. The first is that this black hole, located in a galaxy about 1.8 billion light years from Earth, completely shredded the largest star astronomers have known to be destroyed in a TDE. The other, also intriguing, possibility is that in previous TDEs the star wasnt completely ripped apart, but in this event it was. While astronomers continue to study this source and look for others like it, we are reminded just how amazing black holes can be.
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(Credit: X-ray: NASA/CXC/UNH/D.Lin et al, Optical: CFHT, Illustration: NASA/CXC/M.Weiss) XJ1500+0154 Animations](https://i.ytimg.com/vi/WXanjtSw63E/mqdefault.jpg)





