True Polar Wander: Cosmic Wallop May Have Knocked Enceladus’ Equator to the South Pole
Enceladus – a large icy, oceanic moon of Saturn – may have flipped, the possible victim of an out-of-this-world wallop.
While combing through data collected by NASA’s Cassini mission during flybys of Enceladus, astronomers from Cornell, the University of Texas and NASA have found the first evidence that the moon’s axis has reoriented, according to new research published in Icarus.
NASA/JPL-Caltech/ Space Science Institute
Examining the moon’s geological features, the group showed how Enceladus appears to have tipped away from its original axis by about 55 degrees.
“We found a chain of low areas, or basins, that trace a belt across the moon’s surface that we believe are the fossil remnants of an earlier, previous equator and poles,” said lead author Radwan Tajeddine, research associate in Cornell’s Department of Astronomy and a Cassini imaging team associate. “Their pattern reflects spatial variations in the icy shell, consistent with a variety of geological features visible in Cassini images.”
At the moon’s current southern end, active jets discharge water vapor (as well as organic compounds, gases, salts and silica) through vents from an ocean deep beneath the moon’s icy-crust surface. It’s a place technically known as the south polar terrain, and astronomers have nicknamed the long, geologically active fractures “Tiger Stripes” – each about 80 miles long and a little over a mile wide.
Tajeddine believes an asteroid may have struck the moon’s current south polar region when it was closer to the equator in the past. “The geological activity in this terrain is unlikely to have been initiated by internal processes,” he said. “We think that, in order to drive such a large reorientation of the moon, it’s possible that an impact was behind the formation of this anomalous terrain.”
Wobbly, rickety and unsteady after an asteroid’s smack, the physics of Enceladus’ rotation would have eventually re-established stability, a process that likely took over a million years. To do that, the north-south axis needed to change – a mechanism called “true polar wander.”
Radwan Tajeddine/Provided
Millions of years ago, basins were once strung along the equator and poles of Saturn’s icy moon Enceladus, as shown in the left image. Now after the “true polar wander” event, the moon flipped by 55 degrees into its current state, shown on the right.
Enceladus’ topographic and geological features can be explained through geophysical processes, but the moon’s north and south poles are quite different. The south is active and geologically young, while the north is covered in craters and appears much older.
“The differences Cassini has observed between the north and south poles remains peculiar,” Tajeddine said. “Originally, the poles of Enceladus would have been the same, more or less, before true polar wander occurred. The true polar wander hypothesis seems very plausible when we take a combined look at the patterns of highs and lows across the moon’s surface, the physical appearance of surface features and the differences between the current poles.”
Other authors of the research, which posted online April 30 and will officially publish July 1, 2017, “True Polar Wander of Enceladus From Topographic Data,” are Cornell’s Joseph Burns, the Irving Porter Church Professor of Engineering and professor of astronomy; Peter C. Thomas, visiting scientist; and Paul Helfenstein, senior research associate; and Krista M. Soderlund, University of Texas at Austin; Matthew M. Hedman, University of Idaho; and Paul M. Schenk, Lunar and Planetary Institute, Houston. The research was funded by NASA.
Source:
Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.
"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
Please Help Support BeforeitsNews by trying our Natural Health Products below!
Order by Phone at 888-809-8385 or online at https://mitocopper.com M - F 9am to 5pm EST
Order by Phone at 866-388-7003 or online at https://www.herbanomic.com M - F 9am to 5pm EST
Order by Phone at 866-388-7003 or online at https://www.herbanomics.com M - F 9am to 5pm EST
Humic & Fulvic Trace Minerals Complex - Nature's most important supplement! Vivid Dreams again!
HNEX HydroNano EXtracellular Water - Improve immune system health and reduce inflammation.
Ultimate Clinical Potency Curcumin - Natural pain relief, reduce inflammation and so much more.
MitoCopper - Bioavailable Copper destroys pathogens and gives you more energy. (See Blood Video)
Oxy Powder - Natural Colon Cleanser! Cleans out toxic buildup with oxygen!
Nascent Iodine - Promotes detoxification, mental focus and thyroid health.
Smart Meter Cover - Reduces Smart Meter radiation by 96%! (See Video).
| Online: | |
| Visits: | 1,603,888,823 |
| Stories: | 8,151,670 |
Whistler Blowers, Insiders
