Timeline for Antimatter accident afterglow?
Current License: CC BY-SA 4.0
15 events
| when toggle format | what | by | license | comment | |
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| Oct 22, 2021 at 14:47 | comment | added | Starfish Prime | @thegreatemu antiprotons can annihilate antineutrons. An antiproton interacting with a large nucleus is likely to deliver enough energy to disintegrate it into lighter nuclei which may or may not be stable. Removing a neutron from a nucleus not guaranteed to produce long lived radioactive byproducts. | |
| Oct 21, 2021 at 18:24 | comment | added | thegreatemu | for example, proton annihilation on Fe-54 will produce Mn-53, with a 3 million year half-life. Neutron capture on Fe-54 produces Fe-55 with a 2.7 year half-life | |
| Oct 21, 2021 at 17:55 | comment | added | thegreatemu | I think your basic premise is flawed. If anti-hydrogen reacts with anything other than hydrogen, you'll have an excess of neutrons remaining, either nuclei with some fraction of the protons annihilated, or free neutrons from total proton annihilation which will then capture on surrounding material. Either way you will be left with a substantial amount of radioactive elements. Whether any are long-lived would take a bit more thought | |
| Oct 21, 2021 at 17:40 | comment | added | Kevin | @StarfishPrime: Well, that and the fact that it is theoretically the most energy-dense fuel that we currently know to be physically possible. | |
| Oct 21, 2021 at 17:30 | comment | added | SRM | @starfish I may have misunderstood when I last dig into this. Your statement seems consistent with the other comments. I’ll go read up. | |
| Oct 21, 2021 at 17:14 | comment | added | Zeiss Ikon | @JasonGoemaat You might be right. I'm not a physicist, so I'm guessing on how deeply you'd get significant heating. FWIW, the tufa on Mazama (and Vesuvius and many other volcanoes) was near red heat when it was laid down. | |
| Oct 21, 2021 at 17:11 | comment | added | Jason Goemaat | @Zeiss can you give some references? Gamma ray penetration falls off exponentially with depth so I don't see how it would heat rock to a considerable depth. It seems to me the top layers would receive enough energy to vaporize in the explosion and be carried away. I don't see how a substantial thermal reservoir could exist deep underground to maintain a thermal glow on the surface for a century. | |
| Oct 21, 2021 at 17:09 | comment | added | Christopher James Huff | @ZeissIkon the Mount Mazama example may be more due to heat released by minerals being hydrated, but in any case, any remaining original heat remains specifically because of the low thermal conductivity of the rock preventing the heat from escaping through the surface. A visible glow would mean rapid loss of heat that would very quickly cool the surface layers. Induced radiation might keep things warm longer, but after a century I'd expect it to look little different from any other crater, thermally speaking. | |
| Oct 21, 2021 at 14:20 | comment | added | Zeiss Ikon | Don't forget thermal afterglow. Gamma penetrates deeply, so would heat the Lunar rock to considerable depth. This gives a situation similar to (but probably much larger than) what's seen in tufa after a volcanic eruption: ash/pumice deposits on the slopes of Mount Mazama (aka Crater Lake, Oregon) are still hot enough to boil water percolating into the formation after 5500 years. The surface of this crater might still glow faintly in visible light (and surely would, brightly, in long IR) after only a century. | |
| Oct 21, 2021 at 13:54 | comment | added | Starfish Prime | @SRM wrong. it is considered a potential fuel because the annihilation byproducts include a number of charged particles, whose kinetic energy can be readily extracted for power generation or deflected for thrust. | |
| Oct 21, 2021 at 13:02 | comment | added | SRM | Part of the reason antimatter is considered a potential fuel for long-term inhabited starships is precisely that there aren’t many byproducts. | |
| Oct 21, 2021 at 7:14 | comment | added | ADS | I upvote your answer and have question about secondary annihilation. Some antimatter would be scattered around due to radiation pressure. 1. Some would react not only with free protons, but atoms and molecules of moon surface. What consequences will this lead to? 2. Another part would be dropped to outer space. How far would this blowout be? Suppose there are no atmosphere. So anti-protons would fall to surface for some time (which depends on blowout distance and moon gravity). Could you estimate how long it would be? P.S. Unfortunately I'm unable to estimate so can't add my own answer. | |
| Oct 21, 2021 at 5:51 | history | edited | L.Dutch♦ | CC BY-SA 4.0 |
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| Oct 21, 2021 at 5:12 | comment | added | PcMan | As comment because you already say the same: As a general rule, antimatter does not bruise and infect other atoms with neutron bombardment the way nuclear fission or fusion reactions do. It just shreds the atoms, leaving either very much lighter atoms, or more usually just converting the lot into a strong flood of gamma rays that then just go on to massively heat up any unconsumed matter around it, making a huge thermal explosion not much secondary radiation. The residual glow-per-megaton of antimatter is a fraction of a fraction of the same size fusion explosion. | |
| Oct 21, 2021 at 5:03 | history | answered | L.Dutch♦ | CC BY-SA 4.0 |