Editing 1297: Oort Cloud
Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.
The edit can be undone.
Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.
Latest revision | Your text | ||
Line 4: | Line 4: | ||
| 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 many {{w|small Solar System bodies}}, reaching out to roughly 50,000 {{w|Astronomical unit|AU (astronomical units)}} or nearly one {{w|light-year}} from the sun. 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 | + | {{incomplete|Some issues from the discuss page have to be solved.}} |
+ | The {{w|Oort cloud}} is a hypothesized sphere containing many {{w|small Solar System bodies}}, reaching out to roughly 50,000 {{w|Astronomical unit|AU (astronomical units)}} or nearly one {{w|Light-year|light-year}} from the sun. 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 referred to as a comet. If it gets close enough to the sun it may break up entirely. | ||
− | There seems to be no definitive astronomical definition of the word "comet", and definitions can be challenging and problematic [http://suitti.livejournal.com/56460.html?nojs=1], but in general terms a comet is a celestial object consisting of a nucleus containing a huge amount of ices and dust which, when near the sun, has an atmosphere (called {{w|Comet# | + | There seems to be no definitive astronomical definition of the word "comet", and definitions can be challenging and problematic[http://suitti.livejournal.com/56460.html?nojs=1], but in general terms a comet is a celestial object consisting of a nucleus containing a huge amount of ices and dust which, when near the sun, has an atmosphere (called {{w|Comet#Coma_and_tail|coma}}) and perhaps a ‘tail’ of ionized 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 not a comet. In that case the six comet-like tails were suspected to be caused by rapid spinning of that object. |
− | + | Randal has drawn the hapless Oort Cloud object with it's 'tail' pointing left of frame, i.e. away from the sun, which is how comet tails actually behave regardless of their direction of movement, as they are blown out by the solar wind. (As neither of the other two objects have tails, this lends the picture a comical cartoon-like quality, as when Yosemite Sam is blasted by his own gun and it leaves his moustache tails statically pointing away from the direction of the blast.) | |
− | {{w|C/2012 S1|Comet ISON}} presumably 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 | + | {{w|C/2012 S1|Comet ISON}} presumably 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's not realistic that ISON still would have a tail so far away from the sun. | 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's not realistic that ISON still would have a tail so far away from the sun. | ||
− | On December 2, 2013 NASA released a statement that ISON did not survive its close perihelion with the sun | + | On December 2, 2013 NASA released a statement that ISON did not survive its close perihelion with the sun. |
− | The closest approach of ISON to | + | The closest approach of ISON (or it remains) to Earth will appear on December 27, 2013 by a distance at approx. 60 million kilometers or 37 million miles, 170 hundred times more than the moon. But some sources still claim the remains will hit the earth, an impossible scenario at that vast distance. |
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]. | ||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
==Transcript== | ==Transcript== | ||
Line 41: | Line 36: | ||
:[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. |
+ | |||
+ | ==Trivia== | ||
+ | Some more details on comets: | ||
+ | *The surface of cometary nuclei does reflect less sunlight than asphalt does. Telescopes can't identify or find them until they do have a coma. | ||
+ | *An object at a distance of one light-year would only have an orbital speed about 100 meters per second, the speed of the Earth is about 30 kilometers per second. | ||
+ | *One revolution at that distance would last approximately 20 million years. | ||
{{comic discussion}} | {{comic discussion}} | ||
[[Category:Astronomy]] | [[Category:Astronomy]] |