https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=173.245.49.128&feedformat=atomexplain xkcd - User contributions [en]2024-03-28T17:02:19ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=1517:_Spectroscopy&diff=913341517: Spectroscopy2015-04-27T12:30:05Z<p>173.245.49.128: </p>
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<div>{{comic<br />
| number = 1517<br />
| date = April 27, 2015<br />
| title = Spectroscopy<br />
| image = spectroscopy.png<br />
| titletext = Although right now I'm more excited about ESPRESSO's radial velocity measurements, so I'm listening to This Kiss, her song about measuring "centrifugal motion" on "a rooftop under the sky".<br />
}}<br />
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==Explanation==<br />
{{incomplete|Just the basics. More info needed and links etc.}}<br />
This comic mixes the method of using ''{{w|spectroscopy}}'' to detect oxygen on {{w|exoplanets}} (planets outside our {{w|Solar system}}) with [http://www.azlyrics.com/lyrics/faithhill/breathe.html the lyrics] for the {{w|Faith Hill}} song "{{w|Breathe (Faith Hill song)|Breathe}}". <br />
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From the lyrics: <br />
:''I watch the sunlight'' - examining the spectra of a remote star<br />
:''dance across your face'' - examining the transition of the planet across the star<br />
:''I can '''feel''' you breathe'' - determining that breathable oxygen exists.<br />
In the comic the word '''feel''' have been changed to '''see'''.<br />
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Measuring the light output of stars (spectra) we are able to determine a number of details of the star, including rotation, relative radial velocity, chemical composition, temperature and to some degree, distance and size. As the planet pictured transitions between the star and the observer, and looking at the spectrum received, the viewer is able to determine that the planet is absorbing the specific wavelengths that molecular oxygen absorbs; a clear indication that the planet has large quantities of breathable oxygen. <br />
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http://www.huffingtonpost.com/2015/04/23/nasa-nexss-search-for-life_n_7123788.html<br />
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The title text refers to determining radial velocity in the {{w|ESPRESSO}} program. By noting that the radial velocity of the star changes slightly as the planet that orbits it moves around the star (centrifugal acceleration), the ESPRESSO program should be able to detect the masses of planets as they are moving towards the Earth in their orbit around their distant stars.<br />
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==Transcript==<br />
:[A dark panel with a bright star in the center. To the left a planet (drawn as a new moon) approaches the star. Text is written above in white with two musical notes, one on each side of the text.]<br />
:I watch the sunlight<br />
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:[Same image but now the planet eclipses the star. Small lines around the planet indicate the atmosphere, as seen from the light from the star passing through it. Text is again written above in white with two different musical notes, one on each side of the text.]<br />
:Dance across your face<br />
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:[A white frame with a black line. It Is the spectrum of the planets atmosphere. Two distinct absorbtion peaks are visible. The first one is labeled with an arrow. Text is again written above, now in black, with two, again, different musical notes, one on each side of the text.]<br />
:I can see you breathe<br />
:Label: O<sub>2</sub><br />
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:[Below the panels is the following caption:]<br />
:'''Faith Hill on exoplanet spectroscopy'''<br />
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{{comic discussion}}<br />
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[[Category:Science]]<br />
[[Category:Exoplanets]]</div>173.245.49.128https://www.explainxkcd.com/wiki/index.php?title=Talk:1468:_Worrying&diff=81907Talk:1468: Worrying2015-01-02T09:27:12Z<p>173.245.49.128: </p>
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<div>My first transcript and more-or-less complete explanation. :) Hope I'm not stealing anyone's thunder... [[User:KieferSkunk|KieferSkunk]] ([[User talk:KieferSkunk|talk]]) 07:45, 2 January 2015 (UTC)<br />
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Breaking news being important in movies had already been discussed in xkcd #1387<br />
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http://xkcd.com/1387/<br />
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[[Special:Contributions/173.245.49.128|173.245.49.128]] 09:27, 2 January 2015 (UTC)</div>173.245.49.128https://www.explainxkcd.com/wiki/index.php?title=Talk:706:_Freedom&diff=78521Talk:706: Freedom2014-11-08T16:45:51Z<p>173.245.49.128: Created page with "The last sentence "But you couldn't", is probably also a reference to the fact that even though we and other people have many possibilities, we never expect anyone to actually..."</p>
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<div>The last sentence "But you couldn't", is probably also a reference to the fact that even though we and other people have many possibilities, we never expect anyone to actually use them.</div>173.245.49.128