Editing 2643: Cosmologist Gift
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==Explanation== | ==Explanation== | ||
| + | {{incomplete|Created by a MUON ON SALE, PACKAGED IN A BOX THAT A CAT MIGHT OR MIGHT NOT HAVE DIED IN- Please change this comment when editing this page. Do NOT delete this tag too soon.}} | ||
This comic shows a box labeled to indicate that it contains 30,000 fresh {{w|neutrino}}s and four zeptograms of {{w|dark matter}}. The box is intended as an inexpensive gift for a {{w|cosmologist}}. The gift giver didn't put those things in the box—both are simply passing through it, so the "gift" consists of exactly what was in the empty space it occupies. While the caption suggests this would be a good gift for a cosmologist, what they or anyone else would do with such a box is uncertain. | This comic shows a box labeled to indicate that it contains 30,000 fresh {{w|neutrino}}s and four zeptograms of {{w|dark matter}}. The box is intended as an inexpensive gift for a {{w|cosmologist}}. The gift giver didn't put those things in the box—both are simply passing through it, so the "gift" consists of exactly what was in the empty space it occupies. While the caption suggests this would be a good gift for a cosmologist, what they or anyone else would do with such a box is uncertain. | ||
| − | There are about a billion neutrinos per cubic meter throughout space, produced during the {{w|Big Bang}}.[https://physics.mit.edu/news/journal/physicsatmit_14_conrad/] However, the flux of "freshly produced" {{w|solar neutrino}}s at Earth is around | + | There are about a billion neutrinos per cubic meter throughout space, produced during the {{w|Big Bang}}.[https://physics.mit.edu/news/journal/physicsatmit_14_conrad/] However, the flux of "freshly produced" {{w|solar neutrino}}s at Earth is around 7×10<sup>10</sup>/cm<sup>2</sup>/s, yielding about 2.3 million per cubic meter, implying the box is around 13 liters, about 80% the size of a typical {{w|breadbox}}. |
| − | Four zeptograms is a minuscule mass, equal to four sextillionths of a gram, the mass of about 200 carbon-12 atoms | + | Four zeptograms is a minuscule mass, equal to four sextillionths of a gram, or the mass of about 200 carbon-12 atoms. There is an estimated 0.011 to 0.016 {{w|solar mass}}es of dark matter per cubic {{w|parsec}} locally to the solar system,[https://iopscience.iop.org/article/10.1088/1361-6633/ac24e7/meta] or about 900 zeptograms per cubic meter, suggesting the box is closer to 4 liters. This discrepancy could imply Randall agrees with cosmologists who believe dark matter is partially composed of {{w|primordial black hole}}s,[https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.121301][https://www.sciencedirect.com/science/article/abs/pii/S2212686418301250?via%3Dihub][https://news.yale.edu/2021/12/16/black-holes-and-dark-matter-are-they-one-and-same][https://iopscience.iop.org/article/10.3847/2041-8205/823/2/L25][https://iopscience.iop.org/article/10.1088/1475-7516/2010/04/023] instead of being entirely composed of pervasive subatomic particles. A billion neutrinos have a mass of only about 2×10<sup>-12</sup> zeptograms, at about 0.1 {{w|electron volt}}s each. |
| − | The "local source" mentioned in the title text is a joke about the commercial value of fresh, locally produced items, but the comic means | + | The "local source" mentioned in the title text is a joke about the commercial value of fresh, locally produced items, but the comic means the Sun. It takes solar neutrinos slightly more than 8 minutes to reach Earth once they're emitted, roughly the same time as photons take to make the trip. (This doesn't include the time -- [https://en.wikipedia.org/wiki/Radiative_zone approximately 170,000 years] over many [https://news.stanford.edu/pr/97/971219neutrino.html 28 day neutrino cycles] -- that energy takes to get from the core to where photons are emitted at the Sun's surface.) However, as the neutrinos have been travelling at more than 99.999% of the speed of light, they will have aged by less than two seconds,[https://www.omnicalculator.com/physics/time-dilation] and so are technically even fresher. |
==Transcript== | ==Transcript== | ||
| + | {{incomplete transcript|Do NOT delete this tag too soon.}} | ||
| − | :[A picture of a box with writing on one side | + | :[A picture of a box with writing on one side, saying as follows:] |
:30,000 neutrinos | :30,000 neutrinos | ||
:<small>Freshly produced</small> | :<small>Freshly produced</small> | ||
| − | :Plus 4 zeptograms | + | :Plus 4 zeptograms of dark matter |
| − | |||
:[Caption below the panel]: | :[Caption below the panel]: | ||
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{{comic discussion}} | {{comic discussion}} | ||
| − | [[Category: | + | [[Category:Astronomy]] |
