Propellers by the dozens
Cool image time! The latest image releases from Cassini, taken during its recent close fly-by campaign of the rings of Saturn, focus on the propeller features produced in the rings by larger ring objects. The image on the right, reduced to show here, reveals dozens of propellers of all shapes and sizes.
The original discovery of propellers in this region in Saturn’s rings … was made using several images taken from very close to the rings during Cassini’s 2004 arrival at Saturn. Those discovery images were of low resolution and were difficult to interpret, and there were few clues as to how the small propellers seen in those images were related to the larger propellers Cassini observed later in the mission….
This image, for the first time, shows swarms of propellers of a wide range of sizes, putting the ones Cassini observed in its Saturn arrival images in context. Scientists will use this information to derive a “particle size distribution” for propeller moons, which is an important clue to their origins.
The parallel pattern of rings in the center of the image is a series of density waves in the ring structure, caused by an interaction with one of Saturn’s larger nearby moons.
They have also released the best view we can now expect of a propeller by Cassini.
This is the third and final propeller to be targeted for a close flyby observation during Cassini’s ring-grazing orbits (the period from Nov. 2016 to April 2017 when Cassini’s orbit passed just outside the main rings). …Because propellers are seen in the outermost parts of the main rings, the ring-grazing orbits provided Cassini’s best opportunity to see them up close.
Cassini is now diving between the rings and the planet, so the propellers are farther away.
From the press release: In this ground-breaking new history of early America, historian Robert Zimmerman not only exposes the lie behind The New York Times 1619 Project that falsely claims slavery is central to the history of the United States, he also provides profound lessons about the nature of human societies, lessons important for Americans today as well as for all future settlers on Mars and elsewhere in space.
Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space, is a riveting page-turning story that documents how slavery slowly became pervasive in the southern British colonies of North America, colonies founded by a people and culture that not only did not allow slavery but in every way were hostile to the practice.
Conscious Choice does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.
“Zimmerman’s ground-breaking history provides every future generation the basic framework for establishing new societies on other worlds. We would be wise to heed what he says.” —Robert Zubrin, founder of founder of the Mars Society.
Available everywhere for $3.99 (before discount) at Amazon, Barnes & Noble, and all ebook vendors, or direct from the ebook publisher, ebookit. And if you buy it from ebookit you don't support the big tech companies and I get a bigger cut much sooner.
Cool image time! The latest image releases from Cassini, taken during its recent close fly-by campaign of the rings of Saturn, focus on the propeller features produced in the rings by larger ring objects. The image on the right, reduced to show here, reveals dozens of propellers of all shapes and sizes.
The original discovery of propellers in this region in Saturn’s rings … was made using several images taken from very close to the rings during Cassini’s 2004 arrival at Saturn. Those discovery images were of low resolution and were difficult to interpret, and there were few clues as to how the small propellers seen in those images were related to the larger propellers Cassini observed later in the mission….
This image, for the first time, shows swarms of propellers of a wide range of sizes, putting the ones Cassini observed in its Saturn arrival images in context. Scientists will use this information to derive a “particle size distribution” for propeller moons, which is an important clue to their origins.
The parallel pattern of rings in the center of the image is a series of density waves in the ring structure, caused by an interaction with one of Saturn’s larger nearby moons.
They have also released the best view we can now expect of a propeller by Cassini.
This is the third and final propeller to be targeted for a close flyby observation during Cassini’s ring-grazing orbits (the period from Nov. 2016 to April 2017 when Cassini’s orbit passed just outside the main rings). …Because propellers are seen in the outermost parts of the main rings, the ring-grazing orbits provided Cassini’s best opportunity to see them up close.
Cassini is now diving between the rings and the planet, so the propellers are farther away.
From the press release: In this ground-breaking new history of early America, historian Robert Zimmerman not only exposes the lie behind The New York Times 1619 Project that falsely claims slavery is central to the history of the United States, he also provides profound lessons about the nature of human societies, lessons important for Americans today as well as for all future settlers on Mars and elsewhere in space.
Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space, is a riveting page-turning story that documents how slavery slowly became pervasive in the southern British colonies of North America, colonies founded by a people and culture that not only did not allow slavery but in every way were hostile to the practice.
Conscious Choice does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.
“Zimmerman’s ground-breaking history provides every future generation the basic framework for establishing new societies on other worlds. We would be wise to heed what he says.” —Robert Zubrin, founder of founder of the Mars Society.
Available everywhere for $3.99 (before discount) at Amazon, Barnes & Noble, and all ebook vendors, or direct from the ebook publisher, ebookit. And if you buy it from ebookit you don't support the big tech companies and I get a bigger cut much sooner.
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