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.
"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! Today’s release of new captioned images from the high resolution camera on Mars Reconnaissance Orbiter (MRO) included a wonderful image of the melting carbon dioxide cap of Mars’s south pole. On the right is a cropped portion of the full image, showing what the MRO scientists nickname spiders, features that appear as the CO2 begins to turn into gas.
But these aren’t actual spiders. We call it “araneiform terrain,” to describe the spider-like radiating channels that form when carbon dioxide ice below the surface heats up and releases. This is an active seasonal process we don’t see on Earth. Like dry ice on Earth, the carbon dioxide ice on Mars sublimates as it warms (changes from solid to gas) and the gas becomes trapped below the surface.
Over time the trapped carbon dioxide gas builds in pressure and is eventually strong enough to break through the ice as a jet that erupts dust. The gas is released into the atmosphere and darker dust may be deposited around the vent or transported by winds to produce streaks. The loss of the sublimated carbon dioxide leaves behind these spider-like features etched into the surface.
The image above shows older spiders, formed during past seasonal events. If you click on the image you can see the full image, which shows darker spiders produced by this season’s cycle.
My July fund-raiser for Behind the Black is now over. The support from my readers was unprecedented, making this July campaign the best ever, twice over. What a marvelous way to celebrate the website's tenth anniversary!
Thank you! The number of donations in July, and continuing now at the beginning of August, is too many for me to thank you all personally. Please forgive me by accepting my thank you here, in public, on the website.
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