In a cosmic hit-and-run, icy Saturn moon may have flipped

Related Articles

Related Articles

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 University, 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.

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.”

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.”

CORNELL UNIVERSITY

Download the HeritageDaily mobile application on iOS and Android

More on this topic

LATEST NEWS

Ancient Mosaic Criticises Christianity

An ancient mosaic from a 4th-century house in the centre of the ancient city of Paphos in Cyprus, was a 'pictorial' criticism of Christianity according to experts.

Geoscience: Cosmic Diamonds Formed During Gigantic Planetary Collisions

It is estimated that over 10 million asteroids are circling the Earth in the asteroid belt. They are relics from the early days of our solar system, when our planets formed out of a large cloud of gas and dust rotating around the sun.

Vettuvan Koil – The Temple of the Slayer

Vettuvan Koil is a rock-cut temple, located in Kalugumalai, a panchayat town on the ancient trade routes from Kovilpatti to courtallam, in the southern Indian state of Tamil Nadu.

The Testimony of Trees: How Volcanic Eruptions Shaped 2000 Years of World History

Researchers have shown that over the past two thousand years, volcanoes have played a larger role in natural temperature variability than previously thought, and their climatic effects may have contributed to past societal and economic change.

Sentinels of Ocean Acidification Impacts Survived Earth’s Last Mass Extinction

Two groups of tiny, delicate marine organisms, sea butterflies and sea angels, were found to be surprisingly resilient--having survived dramatic global climate change and Earth's most recent mass extinction event 66 million years ago.

The Venerable Ensign Wasp, Killing Cockroaches For 25 million Years

An Oregon State University study has identified four new species of parasitic, cockroach-killing ensign wasps that became encased in tree resin 25 million years ago and were preserved as the resin fossilized into amber.

Modern Humans Reached Westernmost Europe 5,000 Years Earlier Than Previously Known

Modern humans arrived in the westernmost part of Europe 41,000 - 38,000 years ago, about 5,000 years earlier than previously known, according to Jonathan Haws, Ph.D., professor and chair of the Department of Anthropology at the University of Louisville, and an international team of researchers.

Akrotiri – The Ancient Town Buried by a Volcano

Akrotiri is an archaeological site and a Cycladic Bronze Age town, located on the Greek island of Santorini (Thera) near the present-day village of Akrotiri (for which the prehistoric site is named).

Popular stories

The Secret Hellfire Club and the Hellfire Caves

The Hellfire Club was an exclusive membership-based organisation for high-society rakes, that was first founded in London in 1718, by Philip, Duke of Wharton, and several of society's elites.

Port Royal – The Sodom of the New World

Port Royal, originally named Cagway was an English harbour town and base of operations for buccaneers and privateers (pirates) until the great earthquake of 1692.

Matthew Hopkins – The Real Witch-Hunter

Matthew Hopkins was an infamous witch-hunter during the 17th century, who published “The Discovery of Witches” in 1647, and whose witch-hunting methods were applied during the notorious Salem Witch Trials in colonial Massachusetts.

Did Corn Fuel Cahokia’s Rise?

A new study suggests that corn was the staple subsistence crop that allowed the pre-Columbian city of Cahokia to rise to prominence and flourish for nearly 300 years.