APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21)

[APOD Robot]

Spacecraft Rosetta Shows Comet has Two Components

Explanation: Why does this comet's nucleus have two components? The surprising discovery that Comet 67P/Churyumov–Gerasimenko has a double nucleus came late last week as ESA's robotic interplanetary spacecraft Rosetta continued its approach toward the ancient comet's core. Speculative ideas on how the double core was created include, currently, that Comet Churyumov–Gerasimenko is actually the result of the merger of two comets, that the comet is a loose pile of rubble pulled apart by tidal forces, that ice evaporation on the comet has been asymmetric, or that the comet has undergone some sort of explosive event. Pictured above, the comet's unusual 5-km sized comet nucleus is seen rotating over the course of a few hours, with each frame taken 20-minutes apart. Better images -- and hopefully more refined theories -- are expected as Rosetta is on track to enter orbit around Comet Churyumov–Gerasimenko's nucleus early next month, and by the end of the year, if possible, land a probe on it.

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[Guest]

No way that can be asymmetric evaporation/assimilation... That is clearly 2 distinct object that have come together and are on the grand journey together. Very cool to see this level of detail of a nucleus, but higher resolution would be nice; and would probably answer lots more questions. Still... AMAZING...

[ta152h0]

I have a few asimetric ice cubes stuck together in my freezer. Nop impossible to land on. The americans landed NEAR on EROS, a odd shaped rotating object ( and provbably still there )

[Alex-the-great]

Wow, landing on that will be ESA's new roller coaster attraction.

[Ann]

Click to view full size image

Space duck by WOOTinator

As Alex Parker said on this page:

Contact binary? Anvil? Boot? No, the morphology is clear: Churyumov-Gerasimenko is a rubber duckie.

Ann

[Joules]

Center of rotation/mass is within or near the neck. The smaller lobe must mass near as much as the larger, so composition must be different.
Iron/nickel vs rock+ice or mostly rock vs mostly ice?
From uniform albedo, everything looks to be covered with coat of dust.

[MargaritaMc]

http://asterisk.apod.com/viewtopic.php?f=31&t=32292

[saturno2]

Object very interesting

[Till Credner]

No way! It is Santa Claus, who lost one of his boots.

[neufer]

Center of rotation/mass is within or near the neck. The smaller lobe must mass near as much as the larger, so composition must be different.
Iron/nickel vs rock+ice or mostly rock vs mostly ice?

It's not that clear to me that "the duck's head" is necessarily "the smaller lobe" volume-wise.

From uniform albedo, everything looks to be covered with coat of dust.

• Or is 67P covered with snow:

On 6 June 2014 water vapor was detected being released from 67P at a rate of roughly 1 litre per second.

[NGC3314]

Center of rotation/mass is within or near the neck.

Im not sure we know that from this image series. They may have been arbitrarily recentered for display at a central position.

[tomatoherd]

Why do we need a theory as to why it is this shape? Conglomerate ice-rock chunks on earth's surface are any and every shape imaginable. This should be no surprise. At that small size, we'd have a lot more explaining to do if it looked closely spherical.....

[Joules]

They may have been arbitrarily recentered for display at a central position.

Could be. There's no stars visible to verify the background, so we'll have to wait a few weeks for better imagery.

[eSpace]

Just a minor clarification: The actual rotation rate is just over 12 hours rather than a "few hours". Makes a difference when you're trying to put a lander down....

[neufer]

Just a minor clarification: The actual rotation rate is just over 12 hours rather than a "few hours". Makes a difference when you're trying to put a lander down....

Few (?), a. [OE. fewe, feawe.] Not many; small, limited, or confined in number; -- indicating a small portion of units or individuals constituing a whole; often, by ellipsis of a noun, a few people. "Are not my days few?" Job x. 20.

• Hamlet, Prince of Denmark Act 1, Scene 3

LORD POLONIUS: Yet here, Laertes! aboard, aboard, for shame!

• The wind sits in the shoulder of your sail,
  And you are stay'd for. There; my blessing with thee!
  And these few precepts in thy memory
  See thou character. Give thy thoughts no tongue,
  Nor any unproportioned thought his act.
  Be thou familiar, but by no means vulgar.
  Those friends thou hast, and their adoption tried,
  Grapple them to thy soul with hoops of steel;
  But do not dull thy palm with entertainment
  Of each new-hatch'd, unfledged comrade. Beware
  Of entrance to a quarrel, but being in,
  Bear't that the opposed may beware of thee.
  Give every man thy ear, but few thy voice;
  Take each man's censure, but reserve thy judgment.
  Costly thy habit as thy purse can buy,
  But not express'd in fancy; rich, not gaudy;
  For the apparel oft proclaims the man,
  And they in France of the best rank and station
  Are of a most select and generous chief in that.
  Neither a borrower nor a lender be;
  For loan oft loses both itself and friend,
  And borrowing dulls the edge of husbandry.
  This above all: to thine ownself be true,
  And it must follow, as the night the day,
  Thou canst not then be false to any man.

[neufer]

They may have been arbitrarily re-centered for display at a central position.

Could be. There's no stars visible to verify the background, so we'll have to wait a few weeks for better imagery.

This seems highly unlikely, IMO.

Joules is just wrong in assuming that the flat body segment is that much larger than the big head segment.

[Chris Peterson]

Why do we need a theory as to why it is this shape?

Because the shape can teach us about the history of the body.

[Psnarf]

--
Obquote:

QVACK!
QVACK!! QVACK!
-SETI

(Sorry, had to clear my brain of the Bard of Avon, or I'd be reciting that passage all day. -Shakespeare Ear Worm)

[Chris Peterson]

No way that can be asymmetric evaporation/assimilation... That is clearly 2 distinct object that have come together and are on the grand journey together.

There is nowhere near enough information available at this point to make that kind of assertion. All of the suggestions remain viable theories.

[neufer]

No way that can be asymmetric evaporation/assimilation...
That is clearly 2 distinct object that have come together and are on the grand journey together.

There is nowhere near enough information available at this point to make that kind of assertion.

The large number of binary/double asteroids would suggest that this is not an unreasonable assertion.

http://en.wikipedia.org/wiki/90_Antiope

All of the suggestions remain viable theories.

All of the suggestions remain viable hypotheses.

[Chris Peterson]

No way that can be asymmetric evaporation/assimilation...
That is clearly 2 distinct object that have come together and are on the grand journey together.

There is nowhere near enough information available at this point to make that kind of assertion.

The large number of binary/double asteroids would suggest that this is not an unreasonable assertion.

"No way that can be asymmetric evaporation/assimilation... " is an unreasonable assertion.
"That is clearly 2 distinct object that have come together and are on the grand journey together" is an unreasonable assertion.

The unreasonableness has nothing to do with the concepts, and everything to do with the force of support they are given in the face of rather limited evidence.

All of the suggestions remain viable hypotheses.

Actually, they are also viable theories.

[eSpace]

Just a minor clarification: The actual rotation rate is just over 12 hours rather than a "few hours". Makes a difference when you're trying to put a lander down....

Few (?), a. [OE. fewe, feawe.] Not many; small, limited, or confined in number; -- indicating a small portion of units or individuals constituing a whole; often, by ellipsis of a noun, a few people. "Are not my days few?" Job x. 20.

• Hamlet, Prince of Denmark Act 1, Scene 3

LORD POLONIUS: Yet here, Laertes! aboard, aboard, for shame!

• The wind sits in the shoulder of your sail,
  And you are stay'd for. There; my blessing with thee!
  And these few precepts in thy memory
  See thou character. Give thy thoughts no tongue,
  Nor any unproportioned thought his act.
  Be thou familiar, but by no means vulgar.
  Those friends thou hast, and their adoption tried,
  Grapple them to thy soul with hoops of steel;
  But do not dull thy palm with entertainment
  Of each new-hatch'd, unfledged comrade. Beware
  Of entrance to a quarrel, but being in,
  Bear't that the opposed may beware of thee.
  Give every man thy ear, but few thy voice;
  Take each man's censure, but reserve thy judgment.
  Costly thy habit as thy purse can buy,
  But not express'd in fancy; rich, not gaudy;
  For the apparel oft proclaims the man,
  And they in France of the best rank and station
  Are of a most select and generous chief in that.
  Neither a borrower nor a lender be;
  For loan oft loses both itself and friend,
  And borrowing dulls the edge of husbandry.
  This above all: to thine ownself be true,
  And it must follow, as the night the day,
  Thou canst not then be false to any man.

Phew!!

[Ron-Astro Pharmacist]

Sorry Art - Pun intended

Lest Phil canst giver' the what for
since thine didn't oft try
then lets harpoon that yellow ducky
then give it a fry.

[hlwelborn]

mezzzzzmerizing.

[distefanom]

It seems to an Italian's MOZZARELLA: