Astro Blog

By Hannah Richter , Science.  Excerpt: In the late 2000s, planetary scientists scoured data gathered by NASA’s Cassini mission, a Saturn orbiter, about the planet’s mysterious icy moon Titan. Their exciting conclusion: The frozen world harbored an ocean sloshing around tens of kilometers beneath a thick ice shell. The ocean, hundreds of kilometers deep itself, might even be a cauldron for the “prebiotic” organic chemistry that led to life on Earth, they proposed. Now, nearly 2 decades later, researchers think they may have gotten the story all wrong. Research  presented today  here at the American Geophysical Union’s annual meeting and  published in  Nature  claims that although Titan may have once harbored a liquid ocean, today it is frozen, except for smaller melted zones deep beneath the surface. If true, the discovery will upend the long-standing assumption that Saturn’s biggest moon is a water world, like other moons in the outer Solar System,  in...

https://www.science.org/content/article/giant-plume-spotted-erupting-moon-saturn-might-contain-ingredients-life By Ron Cowen, Science.  Excerpt: NASA’s JWST space telescope has observed a 10,000-kilometer-long plume of water vapor jetting into space from Saturn’s moon Enceladus—the largest spray ever detected from the icy world, which is just one-seventh the diameter of Earth’s Moon. ...Planetary scientists view Enceladus as a prime target in the search for extraterrestrial life because beneath its icy crust the moon houses a salty ocean—a good medium for the ingredients of life to mix. ...Researchers describe the results  today in a NASA press release  and in a  paper  accepted at Nature Astronomy. ...NASA’s Cassini mission, which in 2005 discovered the plumes on Enceladus  ... flew through them  seven times during its 13-year mission, discovering organic molecules such as methane and formaldehyde, and hydrogen, a potential energy source for micr...

https://www.sciencemag.org/news/2019/11/how-enceladus-got-its-water-spewing-tiger-stripes Source:   By Adam Mann, Science Magazine. Excerpt: Researchers say they have solved a long-standing mystery about Saturn’s tiny, frozen moon Enceladus: why its south pole features long, water-spewing geysers known as tiger stripes. The study could also help explain why these unique formations aren’t seen on any other satellite in the solar system. Enceladus became a star attraction in 2005, when NASA’s Cassini mission photographed enormous jets of water ice and vapor emanating from four parallel slashes near its south pole. Since then, researchers have detected organic molecules and hydrogen in the jets—potential food for microbes—making Enceladus one of the top destinations in the search for life elsewhere in the Solar System. ...As it orbits around Saturn, Enceladus experiences gravitational tidal forces that squeeze and heat it. ...According to the new study, led by Douglas Hemingway of...

https://www.scientificamerican.com/article/cassinis-ldquo-grand-finale-rdquo-will-be-a-blaze-of-glory/ Source:   By Lee Billings, Scientific American For Investigation:  6.1, 8.2 Excerpt: The Cassini orbiter will burn out, but its legacy won’t fade away. ...For NASA’s Cassini orbiter—its fuel dwindling after 13 years exploring Saturn, along with the planet’s sprawling rings and dozens of icy moons—the end will come Friday at 7:55 A.M. Eastern time. That’s when mission planners project radio communications will be lost with the two-ton, bus-size spacecraft as it plunges into the giant planet’s turbulent atmosphere at more than 122,000 kilometers per hour. ...“We are concluding the longest, deepest, most comprehensive scientific exploration of a remote planetary system ever undertaken, a system so alien it might as well have been orbiting another star in another galaxy,” says Carolyn Porco, the planetary scientist who leads Cassini’s imaging team. “And we have been profoun...

Source:   By JoAnna Wendel, Eos/AGU Excerpt: The Cassini-Huygens mission launched on 15 October 1997, carrying 12 scientific instruments and a 2-meter-wide saucer-shaped probe called Huygens to land on Saturn’s hazy moon Titan. ...Since its arrival at Saturn in 2004, Cassini has traveled more than 3 billion kilometers in more than 200 orbits around Saturn. It has flown by Titan more than 100 times and the icy ocean moon Enceladus 23 times. And on 14 January 2005, when the Huygens probe touched down on Titan, the mission became the first to successfully drop a lander on an outer solar system moon. .... 1. Cassini Revealed Enceladus’s Potentially Habitable Internal Ocean.... 2. Huygens Showed Us Titan, a Possibly Primordial Earthlike World.... 3. Cassini Changed How We Think of “Habitability”.... 4. Cassini Found Enceladus Ocean Material in the E Ring.... 5. Cassini Unlocked Mysteries of Saturn’s Hexagon.... 6. Cassini Showed Us One of Saturn’s Huge, Infrequent Storms.... 7. …And ...

Source:   NASA RELEASE 13-120 Excerpt: ...NASA's Cassini spacecraft has provided the first direct evidence of small meteoroids breaking into streams of rubble and crashing into Saturn's rings. These observations make Saturn's rings the only location besides Earth, the moon, and Jupiter where scientists and amateur astronomers have been able to observe impacts as they occur.  ... Saturn's rings act as very effective detectors of many kinds of surrounding phenomena, including the interior structure of the planet and the orbits of its moons.  ... http://www.nasa.gov/cassini  http:// www.nasa.gov/home/hqnews/2013/apr/HQ_13-120_Saturn_Meteors.html

Source:   NASA Excerpt: …A new scientific model suggests Saturn's rings formed from the shredding of an ancient moon's outer envelope before it finally collided with Saturn.  solarsystem.nasa.gov/yss/display.cfm

Source:    NASA RELEASE: 11-196 Excerpt: NASA's Cassini spacecraft has discovered the best evidence yet for a large-scale saltwater reservoir beneath the icy crust of Saturn's moon Enceladus. The data came from the spacecraft's direct analysis of salt-rich ice grains close to the jets ejected from the moon. …"There currently is no plausible way to produce a steady outflow of salt-rich grains from solid ice across all the tiger stripes other than salt water under Enceladus's icy surface," said Frank Postberg, a Cassini team scientist at the University of Heidelberg, Germany, and the lead author on the paper.  …This finding is a crucial new piece of evidence showing that environmental conditions favorable to the emergence of life can be sustained on icy bodies orbiting gas giant planets," said Nicolas Altobelli, the European Space Agency's project scientist for Cassini. …Cassini's ultraviolet imaging spectrograph also recently obtained complemen...

Source:   N ASA RELEASE: 11-151 Excerpt:  ...NASA's Cassini spacecraft and a European Southern Observatory ground-based telescope tracked the growth of a giant early-spring storm in Saturn's northern hemisphere so powerful it stretches around the entire planet. The rare storm has been wreaking havoc for months and shot plumes of gas high into the planet's atmosphere. ...The storm produced a 3,000-mile-wide (5,000-kilometer-wide) dark vortex, possibly similar to Jupiter's Great Red Spot, within the turbulent atmosphere. "Nothing on Earth comes close to this powerful storm," says Leigh Fletcher, the study's lead author....  See also www.nasa.gov/home/hqnews/2011/jul/HQ_11-220_Cassini_Big_Storm.html www.nasa.gov/home/hqnews/2011/may/HQ_11-151_Cassini_Saturn.html

Source:   Teolis, Science Excerpt: The flyby measurements of the Cassini spacecraft at Saturn’s moon Rhea reveal a tenuous oxygen (O2)–carbon dioxide (CO2) atmosphere. The atmosphere appears to be sustained by chemical decomposition of the surface water ice …. www.sciencemag.org/content/330/6012/1813.full

Source:    NASA RELEASE: 10-335 Excerpt: NASA's Cassini spacecraft has found possible ice volcanoes on Saturn's moon Titan that are similar in shape to those on Earth that spew molten rock. "When we look at our new 3-D map of Sotra Facula on Titan, we are struck by its resemblance to volcanoes like Mt. Etna in Italy, Laki in Iceland and even some small volcanic cones and flows near my hometown of Flagstaff," said Randolph Kirk, who led the 3-D mapping work, and is a Cassini radar team member and geophysicist at the U.S. Geological Survey (USGS) Astrogeology Science Center in Flagstaff, Ariz....  www.nasa.gov/home/hqnews/2010/dec/HQ_10-335_Cassini_Volcanoes.html