Active sinkholes found on Comet 67P/C-G
Cool image time! Using Rosetta’s high resolution camera scientists have located a number of active pits similar to sinkholes on Earth on Comet 67P/C-G.
Based on the Rosetta observations, the team has proposed a model for the formation of these sinkholes. A source of heat beneath the comet’s surface causes ices (primarily water, carbon monoxide and carbon dioxide) to sublimate. The voids created by the loss of these ice chunks eventually grow large enough that their ceilings collapse under their own weight, giving rise to the deep, steep-sided circular pits seen on the surface of comet 67P/Churyumov-Gerasimenko.
The collapse exposes comet ices to sunlight for the first time, which causes the ice chunks to begin sublimating immediately. These deeper pits are therefore thought to be relatively young. Their shallower counterparts, on the other hand, are most likely older sinkholes with more thoroughly eroded sidewalls and bottoms that have been filled in by dust and ice chunks.
Essentially, they have found that decay of the comet’s nucleus has been mostly gentle and steady, rather than explosive, punctuated with sudden abrupt events.
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 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! Using Rosetta’s high resolution camera scientists have located a number of active pits similar to sinkholes on Earth on Comet 67P/C-G.
Based on the Rosetta observations, the team has proposed a model for the formation of these sinkholes. A source of heat beneath the comet’s surface causes ices (primarily water, carbon monoxide and carbon dioxide) to sublimate. The voids created by the loss of these ice chunks eventually grow large enough that their ceilings collapse under their own weight, giving rise to the deep, steep-sided circular pits seen on the surface of comet 67P/Churyumov-Gerasimenko.
The collapse exposes comet ices to sunlight for the first time, which causes the ice chunks to begin sublimating immediately. These deeper pits are therefore thought to be relatively young. Their shallower counterparts, on the other hand, are most likely older sinkholes with more thoroughly eroded sidewalls and bottoms that have been filled in by dust and ice chunks.
Essentially, they have found that decay of the comet’s nucleus has been mostly gentle and steady, rather than explosive, punctuated with sudden abrupt events.
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 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
How does heat get inside the comet, without having been on the outside first?