A rock on Bennu
Click for full image (which is rotated 180 degrees).
Cool image time! The OSIRIS-REx science team today released a close-up image of the surface of the asteroid Bennu. The image on the right is a cropped and rotated section of that image, focusing on the image’s star, its largest rock.
The boulders on Bennu’s surface sport a variety of surface textures, from smooth, to hummocky, striated, and crumbly “cauliflower” in nature. The large boulder in the image center is ~92 ft (~28 m) across and has a somewhat round shape, though many smaller boulders surrounding it are very angular. Some of these appear to be fragments that may have disaggregated from the central boulder and display layering effects that may reflect some of the properties of their mineral composition. Other boulders show signs of surface exfoliation and fractures that may have been caused by impacts, mechanical weathering, and other forms of rock breakdown active on Bennu’s surface.
The image was taken from less than a mile away, and shows a spot near the asteroid’s south pole.
Why the larger boulder has a rounded look, but the pebbles around it are jagged, is a puzzle.
The science team also revealed today that they have detected plumes of particles being released from the asteroid’s surface. They have also found Bennu to present them with the same problem faced by the Hayabusa-2 team at Ryugu: The asteroid is far rougher than expected.
The higher-than-expected density of boulders means that the mission’s plans for sample collection, also known as Touch-and-Go (TAG), need to be adjusted. The original mission design was based on a sample site that is hazard-free, with an 82-foot (25-meter) radius. However, because of the unexpectedly rugged terrain, the team hasn’t been able to identify a site of that size on Bennu. Instead, it has begun to identify candidate sites that are much smaller in radius.
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 or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. 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
Click for full image (which is rotated 180 degrees).
Cool image time! The OSIRIS-REx science team today released a close-up image of the surface of the asteroid Bennu. The image on the right is a cropped and rotated section of that image, focusing on the image’s star, its largest rock.
The boulders on Bennu’s surface sport a variety of surface textures, from smooth, to hummocky, striated, and crumbly “cauliflower” in nature. The large boulder in the image center is ~92 ft (~28 m) across and has a somewhat round shape, though many smaller boulders surrounding it are very angular. Some of these appear to be fragments that may have disaggregated from the central boulder and display layering effects that may reflect some of the properties of their mineral composition. Other boulders show signs of surface exfoliation and fractures that may have been caused by impacts, mechanical weathering, and other forms of rock breakdown active on Bennu’s surface.
The image was taken from less than a mile away, and shows a spot near the asteroid’s south pole.
Why the larger boulder has a rounded look, but the pebbles around it are jagged, is a puzzle.
The science team also revealed today that they have detected plumes of particles being released from the asteroid’s surface. They have also found Bennu to present them with the same problem faced by the Hayabusa-2 team at Ryugu: The asteroid is far rougher than expected.
The higher-than-expected density of boulders means that the mission’s plans for sample collection, also known as Touch-and-Go (TAG), need to be adjusted. The original mission design was based on a sample site that is hazard-free, with an 82-foot (25-meter) radius. However, because of the unexpectedly rugged terrain, the team hasn’t been able to identify a site of that size on Bennu. Instead, it has begun to identify candidate sites that are much smaller in radius.
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 or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. 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
This makes me think about eating Frosted Flakes as a kid. Even then at a young age I noticed how the larger, more intact flakes were at the top of the bag and the smaller broken bits were packed at the bottom. I always loved getting to the bottom of the bag because that’s where the highest concentration of sugary powder was.
I suppose on Bennu, a captured dense metal-rich asteroid would slowly be absorbed into the center with the lighter rocks remaining on top.
You could also move Bennu around by picking up small rocks and throwing them away. I need to patent a modified baseball pitching machine for this. :-p