Editing 1297: Oort Cloud
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| title = Oort Cloud | | title = Oort Cloud | ||
| image = oort_cloud.png | | image = oort_cloud.png | ||
− | | titletext = ...I wanna try. Hang on, be right back. | + | | titletext = ... I wanna try. Hang on, be right back. |
}} | }} | ||
==Explanation== | ==Explanation== | ||
− | The {{w|Oort cloud}} is a hypothesized sphere containing | + | {{incomplete|Some issues from the discuss page have to be solved.}} |
+ | The {{w|Oort cloud}} is a hypothesized sphere containing material old as our solar system is, reaching out to roughly 50,000 {{w|Astronomical unit|AU (astronomical units)}} or nearly one {{w|Light-year|light-year}} from the sun. It contains many {{w|small Solar System bodies}}, consisting of unknown material. Gravitational forces from passing stars or collisions with other objects sometimes perturb one of these bodies enough to let it fall into the inner solar system. When it gets closer to the Sun (which is just a bright dot at that far distance) it warms up, and some of its mass is lost as gas and dust, making it more visible as an object commonly refered to as a comet. A new {{w|comet}} is born, and if it gets close enough to the sun it may break up entirely. | ||
− | + | Though definition of objects far from our position in the solar system is difficult and subject to dispute, a comet can be defined as a celestial object consisting of a nucleus of ice and dust and, when near the sun, a ‘tail’ of gas and dust particles pointing away from the sun. | |
− | The comet pictured here upon its return strangely resembles the unusual asteroid {{w|P/2013 P5}}. | + | The comet pictured here upon its return strangely resembles the unusual asteroid {{w|P/2013 P5}}. It sported six comet-like tails, but it's still not a comet. In that case the six comet-like tails were suspected to be caused by rapid spinning of that object. |
− | + | {{w|C/2012 S1|Comet ISON}} came from the Oort cloud and reached its closest approach to the sun ({{w|Apsis|perihelion}}) on the day before this comic was published. The comet passed very close to the sun, at a distance of 1,860,000 kilometers or 1,150,000 miles from the centre of the sun. It was thus within one sun-diameter of the surface of the sun itself (diameter of sun = 1,391,000 km). At that distance the temperature, at approx. 2,700 degrees Celsius, vaporizes rock as well as ice and can break the comet apart entirely. | |
− | + | The broken-up object here is presumed to be ISON, and is labeled as such in the transcript, even though Randall hasn't unambiguously identified it. Note that it is not realistic that ISON still would have a tail so far away. | |
− | The | + | The closest approach of ISON, or its remains, to Earth will be on December 27, 2013 but it's not clear how visible the comet will be. |
− | + | December 2, 2013 NASA has released a statement that ISON did not survive its close perihelion with the sun. | |
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This video shows an animation of the encounter at the sun: [http://stereo-ssc.nascom.nasa.gov/browse/2013/11/28/ahead_20131128_cor2_rdiff_512.mpg ISON 28.11.2013]. | This video shows an animation of the encounter at the sun: [http://stereo-ssc.nascom.nasa.gov/browse/2013/11/28/ahead_20131128_cor2_rdiff_512.mpg ISON 28.11.2013]. | ||
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==Transcript== | ==Transcript== | ||
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:[Pause while ISON checks it out off screen.] | :[Pause while ISON checks it out off screen.] | ||
− | :ISON ( | + | :ISON (appears burnt): Wow. Do NOT go over there. |
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{{comic discussion}} | {{comic discussion}} | ||
[[Category:Astronomy]] | [[Category:Astronomy]] |