Dione’s global geology
Cool image time! The picture of Saturn’s moon Dione, taken by Cassini in April 2015 and reduced in size to show here, shows a range of global tectonic geological features. The impact craters we of course understand, but the white linear features are more puzzling. They are probably related to a heating and cooling process, but the full nature of that process is at present not fully understood. Tidal effects and the planet’s cooling over time both contributed, but to what extent is not yet known. Add on top of that the violent effect of impact and the process gets even more complicated. Moreover, do the linear features suggest present geological activity, or are they evidence of past events? Your guess is as good as mine.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Cool image time! The picture of Saturn’s moon Dione, taken by Cassini in April 2015 and reduced in size to show here, shows a range of global tectonic geological features. The impact craters we of course understand, but the white linear features are more puzzling. They are probably related to a heating and cooling process, but the full nature of that process is at present not fully understood. Tidal effects and the planet’s cooling over time both contributed, but to what extent is not yet known. Add on top of that the violent effect of impact and the process gets even more complicated. Moreover, do the linear features suggest present geological activity, or are they evidence of past events? Your guess is as good as mine.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Dione is one of the Saturn moons which are thought to have been formed recently, just 100 million years ago (2-3% of the age of the Solar System). This deduced from the orbital mechanics of the moon system.
http://www.seti.org/weeky-lecture/orbital-dynamics-suggests-recent-formation-saturns-moons
As material from the rings move beyond the Roche limit, they are able to accrete to a moon. Tidal interaction with the rings makes the moon move outwards, until it gets trapped by already existing moons out there. Dione should be about as old as the Rocky Mountains. Still under construction.
Perhaps the crust is water ice that is covered by a darker layer of dust from the rings. Tidal forces would cause cracks exposing the underlying lighter colored material?