|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Resemblance between Itokawa and Comet Hartley 2
Has anybody else noticed a resemblance between the asteroid Itokawa
and today's EPOXY photos of Comet Hartley 2? Both objects are of similar size and show very rough, rubble strewn ends and yet very smooth middle sections. Itokawa may indeed be a blown out comet, while Hartley 2 seems to be in the prime of comet life. But what is causing the dichotomy of extremely broken, rubbled vs. very smooth surfaces for both of these objects? Is this a pattern for things to come with a certain class of objects? |
#2
|
|||
|
|||
Resemblance between Itokawa and Comet Hartley 2
stargene wrote:
Has anybody else noticed a resemblance between the asteroid Itokawa and today's EPOXY photos of Comet Hartley 2? Both objects are of similar size and show very rough, rubble strewn ends and yet very smooth middle sections. Itokawa may indeed be a blown out comet, while Hartley 2 seems to be in the prime of comet life. But what is causing the dichotomy of extremely broken, rubbled vs. very smooth surfaces for both of these objects? Is this a pattern for things to come with a certain class of objects? Yes, lots of people have commented on this. There has been quite a thread on Yahoogroup's Minor Planet Mailing List. The consensus is that we're looking at the "Brazil nut effect" -- shake the bottle of mixed nuts and the big ones rise to the top. Something hits the nucleus from time to time, and the bigger rocks go to the regions of highest potential while the smaller grains go to the regions of lowest potential. Rotation dominates over gravity for something this small, so the rocks wind up far from the axis of rotation and the grains wind up close to it. -- Bill Owen |
#3
|
|||
|
|||
Resemblance between Itokawa and Comet Hartley 2
Bill Owen ) writes:
stargene wrote: Has anybody else noticed a resemblance between the asteroid Itokawa and today's EPOXY photos of Comet Hartley 2? Both objects are of similar size and show very rough, rubble strewn ends and yet very smooth middle sections. Itokawa may indeed be a blown out comet, while Hartley 2 seems to be in the prime of comet life. But what is causing the dichotomy of extremely broken, rubbled vs. very smooth surfaces for both of these objects? Is this a pattern for things to come with a certain class of objects? Yes, lots of people have commented on this. There has been quite a thread on Yahoogroup's Minor Planet Mailing List. The consensus is that we're looking at the "Brazil nut effect" -- shake the bottle of mixed nuts and the big ones rise to the top. Something hits the nucleus from time to time, and the bigger rocks go to the regions of highest potential while the smaller grains go to the regions of lowest potential. Rotation dominates over gravity for something this small, so ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^ What does this mean? Not that the rotational speed exceed the escape speed, surely? --John Park the rocks wind up far from the axis of rotation and the grains wind up close to it. -- Bill Owen |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Comet Hartley Images | Sam Wormley[_2_] | Amateur Astronomy | 13 | November 11th 10 03:33 AM |
EPOXI Successfully Flies by Comet Hartley 2 | Rick Jones[_3_] | Policy | 2 | November 6th 10 03:30 AM |
Comet Cometh: Hartley 2 Visible in Night Sky | Painius | Misc | 0 | October 20th 10 08:22 AM |
Comet Hartley 2 (Binocular Obs.) | Sketcher | Amateur Astronomy | 2 | October 1st 10 05:05 AM |
Comet Hartley 2 | Sketcher | Amateur Astronomy | 7 | September 12th 10 09:53 PM |