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Astronomy Picture of the Day -- The Missing Craters of Asteroid Itokawa
NASA ^ | February 09, 2014 | (see photo credit)

Posted on 02/09/2014 12:19:45 PM PST by SunkenCiv

Explanation: Where are the craters on asteroid Itokawa? Missing -- unexpectedly. The Japanese robot probe Hayabusa approached the Earth-crossing asteroid in 2005 and returned pictures showing a surface unlike any other Solar System body yet photographed -- a surface possibly devoid of craters. The leading hypothesis for the lack of common circular indentations is that asteroid Itokawa is a rubble pile -- a bunch of rocks and ice chunks only loosely held together by a small amount of gravity. If so, craters might not form so easily -- or be filled in whenever the asteroid gets jiggled by a passing planet or struck by a massive meteor. Recent Earth-based observations of asteroid Itokawa have shown that one part of the interior even has a higher average interior density than the other part, another unexpected discovery. The Hayabusa mission returned soil samples from Itokawa which are also giving clues the ancient history of the unusual asteroid and our entire Solar System.

February 09, 2014

(Excerpt) Read more at 129.164.179.22 ...


TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: apod; asteroid; asteroiditokawa; astronomy; hayabusa; itokawa; japan; science
[Credit & Copyright: ISAS, JAXA]

1 posted on 02/09/2014 12:19:45 PM PST by SunkenCiv
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To: brytlea; cripplecreek; decimon; bigheadfred; KoRn; Grammy; married21; steelyourfaith; Mmogamer; ...
APOD's 2014 calendar is now available.
The Big One

2 posted on 02/09/2014 12:21:20 PM PST by SunkenCiv (http://www.freerepublic.com/~mestamachine/)
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To: SunkenCiv

That’s strange. Thanks for the post.


3 posted on 02/09/2014 12:25:27 PM PST by FlingWingFlyer (ObamaCare. The "global warming" of healthcare plans.)
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To: SunkenCiv

Rock of Ages.


4 posted on 02/09/2014 12:26:50 PM PST by bmwcyle (People who do not study history are destine to believe really ignorant statements.)
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To: SunkenCiv

Probably recently broken apart and then reformed. When a potato starts looking that bad, do you throw it out or make soup?


5 posted on 02/09/2014 12:32:46 PM PST by Telepathic Intruder (The only thing the Left has learned from the failures of socialism is not to call it that)
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To: SunkenCiv

Does it melt and re-freeze?


6 posted on 02/09/2014 12:36:24 PM PST by Triple (Socialism denies people the right to the fruits of their labor, and is as abhorrent as slavery)
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To: SunkenCiv


7 posted on 02/09/2014 12:40:23 PM PST by Chode (Stand UP and Be Counted, or line up and be numbered - *DTOM* -vvv- NO Pity for the LAZY - 86-44)
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To: FlingWingFlyer; bmwcyle; Telepathic Intruder; Triple; Chode
This article reiterates the 'rubble pile' explanation, but notes that one end is lower density than the other. That could be suggestive of water ice. My view is that all the Earth-crossers formerly were part of now-extinct comets.
KEYWORDS: asteroid; asteroiditokawa; hayabusa; itokawa

8 posted on 02/09/2014 1:01:30 PM PST by SunkenCiv (http://www.freerepublic.com/~mestamachine/)
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To: SunkenCiv
that's a valid explanation
9 posted on 02/09/2014 1:10:59 PM PST by Chode (Stand UP and Be Counted, or line up and be numbered - *DTOM* -vvv- NO Pity for the LAZY - 86-44)
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To: SunkenCiv

That’s interesting, actually. Then they’re constantly being replenished even with the occasional Tunguska event. There’s just a tiny whisper of gravity holding asteroids together, however. Low density does not necessarily imply light elements.


10 posted on 02/09/2014 1:29:47 PM PST by Telepathic Intruder (The only thing the Left has learned from the failures of socialism is not to call it that)
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11 posted on 02/09/2014 1:31:31 PM PST by shibumi (Cover it with gas and set it on fire.)
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12 posted on 02/09/2014 1:56:42 PM PST by RedMDer (Happy with this, America? Make your voices heard. 2014 is just around the corner. ~ Sarah Palin)
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To: Chode

An Asteroid, Cobbled Together
ScienceNOW Daily News | 2 June 2006 | Phil Berardelli
Posted on 6/3/2006 3:34:15 AM by neverdem
http://www.freerepublic.com/focus/news/1642717/posts


13 posted on 02/09/2014 2:17:14 PM PST by SunkenCiv (http://www.freerepublic.com/~mestamachine/)
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To: Telepathic Intruder

Quite right, there could be voids in the less dense part, much as there may be in one of Mars’ moons.


14 posted on 02/09/2014 2:17:52 PM PST by SunkenCiv (http://www.freerepublic.com/~mestamachine/)
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To: SunkenCiv
gravity surly works on all things
15 posted on 02/09/2014 2:19:43 PM PST by Chode (Stand UP and Be Counted, or line up and be numbered - *DTOM* -vvv- NO Pity for the LAZY - 86-44)
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To: SunkenCiv

It will go good with the Sour Cream Belt of the Milky Way.

16 posted on 02/09/2014 2:22:01 PM PST by TigersEye (Stupid is a Progressive disease.)
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To: SunkenCiv
"The Hayabusa mission returned soil samples from Itokawa"

huh? thats a pretty big deal- why wasn't I notified?

17 posted on 02/09/2014 2:39:01 PM PST by Mr. K (If you like your constitution, you can keep it...Period.)
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To: SunkenCiv

Haven’t heard that. Deimos I assume?


18 posted on 02/09/2014 2:41:09 PM PST by Telepathic Intruder (The only thing the Left has learned from the failures of socialism is not to call it that)
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To: SunkenCiv
This article reiterates the 'rubble pile' explanation, but notes that one end is lower density than the other. That could be suggestive of water ice. My view is that all the Earth-crossers formerly were part of now-extinct comets.

Unfortunately for your theory, every comet we've analyzed or visited has shown essentially zero water. . . and is indistinguishable from any other asteroid except for orbit and electrical charge.

19 posted on 02/09/2014 2:50:23 PM PST by Swordmaker (This tag line is a Microsoft insult free zone... but if the insults to Mac users continue...)
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To: Telepathic Intruder
The Anatomy of an Asteroid

The Anatomy of an Asteroid

20 posted on 02/09/2014 2:52:21 PM PST by SunkenCiv (http://www.freerepublic.com/~mestamachine/)
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To: TigersEye

Chive got a feeling you’re right.


21 posted on 02/09/2014 2:53:13 PM PST by SunkenCiv (http://www.freerepublic.com/~mestamachine/)
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To: Telepathic Intruder

Phobos.


22 posted on 02/09/2014 3:13:11 PM PST by SunkenCiv (http://www.freerepublic.com/~mestamachine/)
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To: SunkenCiv

Well I had a 50/50 chance.


23 posted on 02/09/2014 3:19:26 PM PST by Telepathic Intruder (The only thing the Left has learned from the failures of socialism is not to call it that)
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To: SunkenCiv

If you passed that on a hillside on earth, you’d think, breccia and pass it by.


24 posted on 02/09/2014 3:29:15 PM PST by JimSEA
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To: Swordmaker

“Extinct comet” implies that all the ice has been sublimated. Some comets break up due to outgassing, and I assume some just become extinct and turn into small asteroids. Maybe some break up and then reform, leaving no ancient craters. It’s just interesting, whether it be wrong or right.


25 posted on 02/09/2014 3:30:44 PM PST by Telepathic Intruder (The only thing the Left has learned from the failures of socialism is not to call it that)
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To: Telepathic Intruder

I couldn’t rememember, and started to look for Deimos topics. :’)


26 posted on 02/09/2014 3:37:41 PM PST by SunkenCiv (http://www.freerepublic.com/~mestamachine/)
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To: TigersEye
Paging Dr. Spudis ...
27 posted on 02/09/2014 4:09:45 PM PST by mikrofon (Space BUMP)
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To: mikrofon

LOL He looks a bit like a potato.


28 posted on 02/09/2014 4:11:44 PM PST by TigersEye (Stupid is a Progressive disease.)
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To: JimSEA

:’) The surface of most asteroids probably look a lot like Itokawa — small bits of debris pulled in by the slight gravity. Due to relative lack of competition, asteroids have a large sphere of influence.


29 posted on 02/09/2014 5:39:19 PM PST by SunkenCiv (http://www.freerepublic.com/~mestamachine/)
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