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One of her observations regards the fact that {{w|Sirius}} is a {{w|binary star}}, a system where two stars orbit each other. So even though it is the brightest star as seen from Earth we only really see one of them, as the other is, to quote the host, "not even trying". Sirius A is "large" and "bright" {{w|main sequence}} white star, while Sirius B is a {{w|white dwarf}} with a little under half the mass, 0.49% the radius and only 0.22% the luminosity of Sirius A.
 
One of her observations regards the fact that {{w|Sirius}} is a {{w|binary star}}, a system where two stars orbit each other. So even though it is the brightest star as seen from Earth we only really see one of them, as the other is, to quote the host, "not even trying". Sirius A is "large" and "bright" {{w|main sequence}} white star, while Sirius B is a {{w|white dwarf}} with a little under half the mass, 0.49% the radius and only 0.22% the luminosity of Sirius A.
  
{{w|Andromeda Galaxy|Andromeda}} is the largest galaxy in our {{w|Local Group}}. It is 220,000 light years across and contains a trillion stars. Humans have difficulty conceptualizing distances of this scale. Suffice to say that it is very large.{{Citation needed}}
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{{w|Andromeda Galaxy|Andromeda}} is the largest galaxy in our {{w|Local Group}}. It is 220,000 light years across and contains a billion stars. Humans have difficulty conceptualizing distances of this scale. Suffice to say that it is very large.{{Citation needed}}
  
 
{{w|Betelgeuse}} is the 9th brightest star visible from earth. One of its prominent features is its visible redness. Within the next million years (or maybe only 100,000 years) it is expected to explode as a {{w|supernova}}, which will certainly be a spectacular sight. It could happen anytime now, and the host hopes it will be in her lifetime.
 
{{w|Betelgeuse}} is the 9th brightest star visible from earth. One of its prominent features is its visible redness. Within the next million years (or maybe only 100,000 years) it is expected to explode as a {{w|supernova}}, which will certainly be a spectacular sight. It could happen anytime now, and the host hopes it will be in her lifetime.
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*Sirius is actually a star system consisting of two stars as it is a {{w|binary star}} system. But where Sirius A is twice the size of the {{w|Sun}} and much brighter, then Sirius B is now just a dim {{w|white dwarf}}, the remains from a much larger star that became a {{w|red giant}} before shedding its outer layers and collapsing into its current state around 120 million years ago. So now Sirius A completely outshines Sirius B, which actually is now a dead star with no further fusion going on inside its core.
 
*Sirius is actually a star system consisting of two stars as it is a {{w|binary star}} system. But where Sirius A is twice the size of the {{w|Sun}} and much brighter, then Sirius B is now just a dim {{w|white dwarf}}, the remains from a much larger star that became a {{w|red giant}} before shedding its outer layers and collapsing into its current state around 120 million years ago. So now Sirius A completely outshines Sirius B, which actually is now a dead star with no further fusion going on inside its core.
 
**This is construed by the host as it is barely even trying, as it is now only radiating away the rest of the heat from the now exposed core.
 
**This is construed by the host as it is barely even trying, as it is now only radiating away the rest of the heat from the now exposed core.
*{{w|Andromeda Galaxy|Andromeda}} is a {{w|spiral galaxy}}, like the Milky Way, and it is the largest galaxy in the {{w|Local Group}} where our own galaxy the Milky Way is the second largest. It is one of a few visible objects that are located outside the Milky Way. It is "only" 2.5 million light-years from the Sun and it is heading our way (or vice versa), and will {{w|Andromeda–Milky Way collision|collide with the Milky way}} in about 4 billion years (before the Sun goes into {{w|Sun#After_core_hydrogen_exhaustion|its red giant phase}}). Being 220,000 light years across and consisting of a trillion stars, it is somewhere between 1.2-2.2 times wider than the Milky Way and has 2.5-10 times as many stars. (The local group was also mentioned two comics ago, in [[1642: Gravitational Waves]], together with the much less well known third largest galaxy in the group the {{w|Triangulum Galaxy}}).
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*{{w|Andromeda Galaxy|Andromeda}} is a {{w|spiral galaxy}}, like the Milky Way, and it is the largest galaxy in the {{w|Local Group}} where our own galaxy the Milky Way is the second largest. It is one of a few visible objects that are located outside the Milky Way. It is "only" 2.5 million light-years from the Sun and it is heading our way (or vice versa), and will {{w|Andromeda–Milky Way collision|collide with the Milky way}} in about 4 milliard years (before the Sun goes into {{w|Sun#After_core_hydrogen_exhaustion|its red giant phase}}). Being 220,000 light years across and consisting of a billion stars, it is somewhere between 1.2-2.2 times wider than the Milky Way and has 2.5-10 times as many stars. (The local group was also mentioned two comics ago, in [[1642: Gravitational Waves]], together with the much less well known third largest galaxy in the group the {{w|Triangulum Galaxy}}).
 
**It is therefore true when the host says that it is too big to try to understand, and thinking about it will make your head spin, so she suggests we do not think about it.
 
**It is therefore true when the host says that it is too big to try to understand, and thinking about it will make your head spin, so she suggests we do not think about it.
 
*{{w|Betelgeuse}} is a clearly visible (9th brightest) {{w|Red_supergiant|red supergiant}} {{w|Semiregular_variable_star|variable star}} located in the {{w|Orion (constellation)|constellation of Orion}}. It is one of the largest and most luminous observable stars (12th) and one of the few where it is clear that the light is not white. Most people can see that it is slightly red, whereas most other stars are so faint that they look white despite having different colors (when seeing Orion's two brightest stars, to remember which is which between Rigel and Betelgeuse, its diagonal opposite, just remember: Rigel is "R" like blue, and Betelgeuse is "B" like red). It is expected that Betelgeuse, being at a late stage of its {{w|Stellar_evolution|evolution}}, {{w|Betelgeuse#Approaching_supernova|will go supernova}} within the next million years as a {{w|type II supernova}}. The exact time when it will become a {{w|Supernova}} is so uncertain that it could [http://earthsky.org/brightest-stars/betelgeuse-will-explode-someday#explode just as likely happen tomorrow] as in a million years. When it happens it will not be dangerous to anyone on Earth, but it will likely be visible even during the day, as it may even become as bright as the full Moon.
 
*{{w|Betelgeuse}} is a clearly visible (9th brightest) {{w|Red_supergiant|red supergiant}} {{w|Semiregular_variable_star|variable star}} located in the {{w|Orion (constellation)|constellation of Orion}}. It is one of the largest and most luminous observable stars (12th) and one of the few where it is clear that the light is not white. Most people can see that it is slightly red, whereas most other stars are so faint that they look white despite having different colors (when seeing Orion's two brightest stars, to remember which is which between Rigel and Betelgeuse, its diagonal opposite, just remember: Rigel is "R" like blue, and Betelgeuse is "B" like red). It is expected that Betelgeuse, being at a late stage of its {{w|Stellar_evolution|evolution}}, {{w|Betelgeuse#Approaching_supernova|will go supernova}} within the next million years as a {{w|type II supernova}}. The exact time when it will become a {{w|Supernova}} is so uncertain that it could [http://earthsky.org/brightest-stars/betelgeuse-will-explode-someday#explode just as likely happen tomorrow] as in a million years. When it happens it will not be dangerous to anyone on Earth, but it will likely be visible even during the day, as it may even become as bright as the full Moon.

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