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==Explanation==
 
==Explanation==
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{{incomplete|Created by an ALIEN GHOST EXORCIST - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
  
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In this comic, Cueball states that observations of light that passed through the atmosphere of a distant planet indicate that there are ghosts on that planet, because some of the light was absorbed in a way that is unique to ghosts. This is analogous to how gases or suspended particles absorb certain wavelengths, allowing scientists to identify properties of distant objects using telescopes. The pun is that in this comic "spectral analysis" refers to both {{w|Spectroscopy|the analysis of the light spectrum}} and the analysis of specters (ghosts).
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Spectral analysis as used in the study of exoplanets and other distant objects in space refers to using the intensities of different frequencies of light (and other electromagnetic frequencies) from stars which they occlude to infer data about their chemical composition. This is used to detect certain gases in the atmosphere, such as oxygen, which might suggest life. On the day before this comic was published, NASA announced that spectral analysis of the exoplanet K2-18 b showed abundance of methane and carbon dioxide, and shortage of ammonia, supporting the hypothesis that it may have a water ocean; and there was possible detection of dimethyl sulfide, which on Earth is only produced by life.[https://www.nasa.gov/goddard/2023/webb-discovers-methane-carbon-dioxide-in-atmosphere-of-k2-18b]
  
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{{w|Spectroscopy|Spectral analysis}} is the study of the {{w|electromagnetic spectrum}} that results from the interaction between electromagnetic radiation (including visible light) and matter. In the study of {{w|exoplanet}}s and other distant objects in space, it refers to using the intensities of different frequencies of light (and other electromagnetic radiation) from stars which they occlude to infer data about their chemical composition. This is used to detect certain gases in the atmosphere, such as {{w|Oxygen#Allotropes|free oxygen}}, which might suggest generation by and for Earth-like life. On the day before this comic was published, {{w|NASA}} announced that spectral analysis of the exoplanet {{w|K2-18b}} showed abundance of {{w|methane}} and {{w|carbon dioxide}}, and shortage of {{w|ammonia}}, which are chemical footprints that support the hypothesis that it may have a life-supporting water ocean; and there was possible detection of {{w|dimethyl sulfide}}, which on {{w|Earth}} is only produced by life.[https://www.nasa.gov/goddard/2023/webb-discovers-methane-carbon-dioxide-in-atmosphere-of-k2-18b] If confirmed, these would be very interesting findings, although it may turn out to be less remarkable on closer study (as {{w|Life on Venus#Phosphine|with Venus}} for example).
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"Spectral" can also be used to refer to ghosts or "spectres". Here it is suggested that the planet may have ghosts in its atmosphere due to the light that they absorb, similar to how gases may absorb certain wavelengths. Like many atmospheric gases, ghosts are typically invisible{{Citation needed}}, however they may have their own absorption spectrum distinguishing them from normal gases. The presence of ghosts in an exoplanet's atmosphere can also be considered evidence of (past) alien life.
  
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"Spectral" also has another meaning: relating to specters (ghosts). Hence "exoplanet spectral analysis" could be interpreted as the analysis of ghosts on planets outside the solar system instead of the analysis of the elements that might be present on the planet. "Specter" and "spectrum" have the same etymological root, deriving from Latin "spectrum" meaning "appearance", with a specter specifically referring to a visible shadow or ghost.
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The title text refers to the search for life on Mars, which is done largely to investigate the origin of life. Ghosts may serve as signs of past life on Mars.
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The title text refers to the search for past life on Mars. Just like the comic, it also humorously conflates the practice of searching for signs of past life such as specific molecules or fossils (which NASA does actively search for), versus the disreputable practice of searching for ghosts, with this conflation framing both as an equally scientific indication of past life. In a very loose sense, real signs such as gases or fossils could be considered "ghosts" of past life.
 
  
 
==Transcript==
 
==Transcript==
 
{{incomplete transcript|Do NOT delete this tag too soon.}}
 
{{incomplete transcript|Do NOT delete this tag too soon.}}
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:: [Cueball is holding a stick and pointing at a slide with two ghosts and a planet]
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:: [Cueball is holding a stick and pointing at a slide with two ghosts and a planet/star]
 
:: Cueball: When the planet passed in front of its host star, some of the light was absorbed by ghosts, indicating that the planet is likely haunted.
 
:: Cueball: When the planet passed in front of its host star, some of the light was absorbed by ghosts, indicating that the planet is likely haunted.
  
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[[Category:Comics featuring Cueball]]
 
[[Category:Comics featuring Cueball]]
 
[[Category:Astronomy]]
 
[[Category:Astronomy]]
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[[Category:Exoplanets]]
 
 
[[Category:Aliens]]
 
[[Category:Aliens]]
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[[Category:Puns]]
 

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