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Will excess radiation leak through to Earth during re-ionization?
by KRAKRISMOTT 3y ago
Will excess radiation leak through to Earth during re-ionization?
- Jeff_Brown 3y agoIf the holes are quickly healed by sunlight, and only local to where a satellite is launched, the answer would seem to be no.
- arbuge 3y ago> One famous example occured on August 25, 2017, when a Falcon 9 rocket carrying Taiwan’s FORMOSAT-5 satellite created a hole four times bigger than the state of California. Doesn't sound too local to me.
- Jeff_Brown 3y agoGood point. Deserves some numbers. California's area is about 500 thousand km^2, and the Earth's is about 500 million, which means the side facing the Sun is about 250 million, so we're talking about 0.2% of the area facing the sun. Suppose the hole takes six hours to heal (the article makes it sound like it takes much less), and suppose there's a launch every month (since launches have in the past carried 600 satellites at once, that seems plausible, no?), and suppose the hole lets in twice as much of whatever radiation we would like the ionosphere to keep out. Then that's an increase of 0.2 * (1/4) * (1/30) %, which is less than 0.002% -- that is, an increase by a factor of less than 1.00002. Not negligible, but if the satellites provide a substantial public good, then it seems worth the cost. I feel like due to StarLink's use in Russia-Ukraine war alone, it more than qualifies.
- coldtea 3y ago>so we're talking about 0.2% of the area facing the sun Doesn't sound small at all.
- saagarjha 3y agoRight, but presumably the effects are greater for the people in California?
- onethought 3y agoBecause the hole was similar sized to their state? I guess so, they will have to deal with increased fame and awareness of the size of their state. People in Oregon on the other hand will continue to be snubbed.
- dylan604 3y agoWe'll start seeing placards attached that says it's known to cause
- cdot2 3y agoYeah they get to see red lights and have trouble with HF HAM radio. If youre aware of other effects please share.
- TaylorAlexander 3y agoAnother way of putting it is that it could potentially affect 40 million people.
- eru 3y agoThere are areas of the globe that are more densely populated than California. But on the other hand, you typically don't launch rockets there.
- TaylorAlexander 3y agoOh I was assuming the launch was actually from Vandeburg in California and that’s why people said the hole was the size of California. But it could have been from Florida.
- dgoldstein0 3y agoShouldn't we also adjust for the fact that the ionosphere has a larger radius than the earth when considering it's surface area? Earth's radius: 6,371 km Ionosphere: 60-300km ... If we use the inner edge of the ionosphere we get about 2% more surface area whereas the outer edge gives us 9.6%. Probably the right number to use is somewhere in between.
- tigershark 3y agoSpacex it’s aiming to launch in 2023 about 100 times per year, and they are not too far behind given that they launched already 49 times. The launch cadence is going to drastically increase once starship is available. It seems a quite bigger impact that your numbers show. You used 12 launches per year, so you were off by an order of magnitude.
- seadan83 3y agoI applaud the attempt to quantify. Couple nits: - frequency estimate should be more aggressive, should be looking for an upper bound on all numbers to quantify max potential impact. I would crank that up to once a day or more. - a hole allowing twice as much sounds like a comolete guess. Could it be 100x, 10,000x? or perhaps less than 10%? Other comments make the ozone layer sound more important. The hole punching effects on that layer are unknown (to me and the article does not mention it). In effect, this could be a light show, or it could be a routine perforation of each layer of the atmosphere (more data needed) - that extra radiation is not spread out across the area of the earth. Instead how many people and animals are present under that hole. Everyone underneath the hole presumably would get the full blast. Thus, it is simple, those people get twice the radiation, whatever that factor is, it is not averaged across the whole planet because it is a local effect. Thus, the area sizes only matter for determining how many people and animals receive extra exposure. - starlink donated their services to Ukraine. That one act of donation does not make it a public good. Starlink is a for profit service, not a public good (some services can be quite good, but that is different from "a public good")
- tmearnest 3y agoYup, I don’t believe there are any consequences to anyone away from the hole. I think the right way to approach this is to consider the unshielded radiation flux over the hole and the time that the hole takes to close. This would give a good back of envelope upper bound of the increase in cancer risk. There’s probably other effects, but all I care about is harm to individuals.
- deleted 3y ago[deleted]
- dfox 3y agoOnly insignificantly. Most of the radiation is filtered/diverted by the magnetosphere. The only really practical effect of the disturbance is making the already hard to predict sky-wave propagation of HF even more harder to predict and characterize. Which is today realistically of an interest to HAMs and mostly as an fallback for intelligence agencies and diplomatic services. Edit: It also somewhat changes the scatter/delay characteristics of GNSS, which may or may not cause a somewhat significant error of the GNSS fix (it probably should not, but it can).
- op00to 3y agoWhat about high frequency trading shops?
- dfox 3y agoThat is completely different definition of HF. And if they use radio (lower latency than fiber, in theory and in right circumstances ), it is somewhere between SHF and EHF (C through V in the IEEE nomenclature), ie. what sane person would informally call “microwave”, not HF.
- jrockway 3y agoThere was a thread on here the other day about HF traders using HF radio.
- tomjakubowski 3y agoYes that's right, also known as shortwave radio. https://spectrum.ieee.org/amp/wall-street-tries-shortwave-radio-to-make-highfrequency-trades-across-the-atlantic-2650277134 https://spectrum.ieee.org/amp/wall-street-tries-shortwave-ra...
- dfox 3y agoWell, the article itself does a pretty good job of describing why it is not an exactly good idea. What it does not say (and what probably nobody suggesting that ever though about) is that the sky-wave propagation mode is either about reflection off the ionosphere or refraction effects of the ionosphere, both of which means that the propagation path is significantly longer and in the refraction case over “slower” medium. The resulting latencies are almost certainly large enough that the whole thing does not make sense even before thinking about the bandwidth and frame sizes.
- perihelions 3y agoDon't believe the ionosphere has any role in any sort of radiation absorption, outside of RF?
- angiosperm 3y agoThe Ozone Layer is considerably lower than the Ionosphere proper, and protects all surface life from ionizing solar UV radiation. It most likely is as damaged by rocket exhaust as the ionosphere, and much more slowly healed. That undoubtedly deserves its own article, which will unavoidably be confused with this one and be considered old news.
- reaperman 3y agoWhy would O3 be damaged by H2O? SpaceX rockets are powered by hydrogen and oxygen and produce water as exhaust.
- HPsquared 3y agoKerosene and oxygen.. Anyway it's probably that the exhaust plume will contain reactive species like nitrogen oxides, maybe the water vapour could have a role. It's not a big effect. Hydrazine powered rockets have a much bigger effect (all those nitrogen oxides) and are still not a very big deal.