Editing 2643: Cosmologist Gift
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==Explanation== | ==Explanation== | ||
+ | {{incomplete|Created by a MUON ON SALE- 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 | + | 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. While the caption states that 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 23,000 per cubic meter. |
− | 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. This discrepancy with the number of solar neutrinos in the box suggests Randall might agree with the cosmologists who believe that dark matter is at least 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 | + | The "local source" mentioned in the title text is the Sun; it takes light and neutrinos 8 minutes to reach Earth once they're emitted. As the neutrinos have been travelling at about 99.999% of the speed of light, they will have aged by only about two seconds,[https://www.omnicalculator.com/physics/time-dilation] so are technically much 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]] |