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

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Expand view Topic review: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21)

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

by neufer » Wed Aug 06, 2014 9:52 pm

Click to play embedded YouTube video.
BillBixby wrote:
Another landing coming up. I hope all the engineers have there DUCKS in a row, know how many feet are in a yard and Yards to the meter. For some reason I worry when different countries with different measurement systems get together to work on a project.
The only folks with "a different measurement system"
are U.S., Liberia & Burma.
http://en.wikipedia.org/wiki/Metric_system wrote:
<<The United States remains the only industrialised country that has not adopted the metric system as its official system of measurement. Many sources also cite Liberia and Burma as the only other countries not to have done so.>>

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

by Ron-Astro Pharmacist » Wed Aug 06, 2014 9:28 pm

Clearly - better pictures are on the way.
Rosetta.jpg
I'm sure more to follow.

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

by Joules » Mon Jul 28, 2014 11:34 pm

Center of mass is in the neck, between larger body and smaller head: http://rosetta.jpl.nasa.gov/news/surfac ... %99s_comet
Overall density of the comet is reportedly between 0.1 and 0.5 g per cubic cm, depending on how calcs are done. See Wikipedia for one value, there are several others computed http://en.wikipedia.org/wiki/67P/Churyu ... erasimenko
That low a density doesn't leave much room for large rigid bodies, yet there they are. Perhaps the unusual shape has thrown off calculations?

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

by Beyond » Tue Jul 22, 2014 8:24 pm

Ann wrote:Spaghettification and meat sauce? :shock: :x
EWWW! That's Gruesome, Ann. :yes: In space, no one can hear you get slurped.

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

by Ann » Tue Jul 22, 2014 8:12 pm

DavidLeodis wrote:Through the "tidal forces" link I learnt a new word:- spaghettification. :P
Spaghettification and meat sauce? :shock: :x

Ann

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

by DavidLeodis » Tue Jul 22, 2014 6:57 pm

Through the "tidal forces" link I learnt a new word:- spaghettification. :P

Re: Few know and fewer care. - Proverb.

by BDanielMayfield » Tue Jul 22, 2014 5:19 pm

Harkenth Art, thou hast miss'd a few.
neufer wrote:
eSpace wrote:
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.

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

by BillBixby » Tue Jul 22, 2014 4:14 pm

Another landing coming up. I hope all the engineers have there DUCKS in a row, know how many feet are in a yard and Yards to the meter. For some reason I worry when different countries with different measurement systems get together to work on a project.

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

by Boomer12k » Tue Jul 22, 2014 12:37 am

Can't wait for the higher resolution pictures, and the landing...


Go, Rosetta, Go!!!!

:---[===] *

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

by distefanom » Mon Jul 21, 2014 10:38 pm

It seems to an Italian's MOZZARELLA:

Image


:lol2: :lol2: :D

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

by hlwelborn » Mon Jul 21, 2014 8:47 pm

mezzzzzmerizing.

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

by Ron-Astro Pharmacist » Mon Jul 21, 2014 7:51 pm

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.

Re: Few know and fewer care. - Proverb.

by eSpace » Mon Jul 21, 2014 7:20 pm

neufer wrote:
eSpace wrote:
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!! :)

Re: APOD: Spacefract Rosetta Shows Comet has... (2014 Jul 21

by Chris Peterson » Mon Jul 21, 2014 4:57 pm

neufer wrote:
Chris Peterson wrote:
Guest wrote:
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.

Re: APOD: Spacefract Rosetta Shows Comet has... (2014 Jul 21

by neufer » Mon Jul 21, 2014 3:33 pm

Chris Peterson wrote:
Guest wrote:
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
Chris Peterson wrote:
All of the suggestions remain viable theories.
All of the suggestions remain viable hypotheses.

Re: APOD: Spacefract Rosetta Shows Comet has... (2014 Jul 21

by Chris Peterson » Mon Jul 21, 2014 2:52 pm

Guest wrote: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.

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

by Psnarf » Mon Jul 21, 2014 2:51 pm

--
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)

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

by Chris Peterson » Mon Jul 21, 2014 2:51 pm

tomatoherd wrote: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.

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

by neufer » Mon Jul 21, 2014 2:50 pm

Joules wrote:
NGC3314 wrote:
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.

Few know and fewer care. - Proverb.

by neufer » Mon Jul 21, 2014 2:35 pm

eSpace wrote:
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.

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

by eSpace » Mon Jul 21, 2014 2:21 pm

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....

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

by Joules » Mon Jul 21, 2014 1:57 pm

NGC3314 wrote: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.

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

by tomatoherd » Mon Jul 21, 2014 1:13 pm

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.....

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

by NGC3314 » Mon Jul 21, 2014 1:08 pm

Joules wrote: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.

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

by neufer » Mon Jul 21, 2014 12:42 pm

Joules wrote:
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.
Joules wrote:
From uniform albedo, everything looks to be covered with coat of dust.
  • Or is 67P covered with snow:
http://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimenko wrote:
On 6 June 2014 water vapor was detected being released from 67P at a rate of roughly 1 litre per second.

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