If the holes are quickly healed by sunlight, and only local to where a satellite is launched, the answer would seem to be no.

> 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.

Good 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.

>so we're talking about 0.2% of the area facing the sun

Doesn't sound small at all.

Right, but presumably the effects are greater for the people in California?

Yeah they get to see red lights and have trouble with HF HAM radio. If youre aware of other effects please share.

We'll start seeing placards attached that says it's known to cause

Because 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.

Another way of putting it is that it could potentially affect 40 million people.

There are areas of the globe that are more densely populated than California.

But on the other hand, you typically don't launch rockets there.

Oh 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.

Shouldn'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.

Spacex 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.

I 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")

Yup, 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.

Only 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).

What about high frequency trading shops?

That 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.

There was a thread on here the other day about HF traders using HF radio.

Yes that's right, also known as shortwave radio.

https://spectrum.ieee.org/amp/wall-street-tries-shortwave-ra...

Well, 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.

Another thing that got posted here a couple days ago was the Burrito Tunnel: https://idlewords.com/2007/04/the_alameda_weehawken_burrito_...

That's where the high-frequency traders should put their fibers ;)

Man that really had me scratching my head for the first few sentences… haha. The fake link was a nice touch to build credibility. I’m not on my desktop where I can view source, but I’m guessing it’s an href pointing back at its self.

Obviously you know more than HFTs which never put thought or engineering into anything. They’re well known dopes who are really bad with technology and money, right?

100% wrong.

This is talking about radio wave frequency, not trading frequency.

The funny thing is that in most ham radio usage, the "high frequency bands" are actually about as low a frequency as most people will ever use. I don't think I've come across anything about low and medium frequencies except in reference materials. People generally use "high frequency", "very high frequency", or "ultra high frequency".

AM radio is medium frequency.

Radio clocks are low frequency.

I’ve found myself explaining that to people a few times. Lower frequencies are also used to communicate with submarines since they propagate better through water.

I’m guessing that when radio first came out frequencies were lower, though I don’t have any facts there.

“Shortwave radio” is another one that’s confusing term these days for the same reason.

Yes, in fact at this moment commercial interests are petitioning the FCC to allocate bandwidth in the HF 2-25mhz range for the purpose of high-speed stock trading: http://www.arrl.org/news/commercial-interests-petition-fcc-f...

They should be banned anyway. The more we can do to make their operations impossible the better.

Their mere existence makes a mockery of the idea of the stock market as a considered reflection of value of companies and explicitly makes it into a gambling den for dead-eyed people competing to have the fastest card counting systems under their suits. If a company is valuable now, it'll be valuable in 5 minutes.

HFTs provide a lot of value to everyone by providing a lot of liquidity and reducing bid/ask spread giving a fairer price to everyone.

> If a company is valuable now, it'll be valuable in 5 minutes.

That’s not necessarily true.

It just so happens that those who advocate and benefit directly from it are the ones who already have the power to make markets. The product of a company is based on its labor utilization, which doesn't change materially in the (very) short timespans of HFT. Liquidity aside, five minutes isn't going to make much of a difference when most people generally wait weeks or months to make major asset purchases like a car or a house, or to be approved for a small business loan. Only the ultra-wealthy car about milliseconds, because they can afford to make such vast and diverse trades in so little time.

Labor utilization is only one piece of a very big puzzle. Other pieces that change more quickly include commodity and supply chain costs, competitor activities, technological advances, and many other factors, all of which can change quite quickly in our globalized world.

"Quite quickly" and "so quickly that a basement full of racks of FPGAs, point-to-point radios, dedicated fibre runs and optical switches are required to extract our value" are maybe not exactly the same thing.

What technological advances are occuring on millisecond timescales?

>>HFTs provide a lot of value to everyone

I think we are going to have very different views as to what the terms "value" and "everyone" mean

because HFT's provide no value at all to the everyday person on mainstreet just looking get by and maybe put 10% of their wages into the stock market for retirement.

if by everyone you mean "the top 1%" and by value you mean "make lots of money at the expense of mainstreet investors" then sure.

> because HFT's provide no value at all to the everyday person

If you participate in the stock market at all, you indirectly benefit from HFTs lowering the bid/ask spread and therefore getting a better price. Now matter how insignificant, but the benefit is there.

Of course if we're dealing in millions, not thousands, then the benefit is more pronounced, but a couple of cents here or there still make a difference.

At the very worst HFT firms are a net neutral.

> "make lots of money at the expense of mainstreet investors"

Can you elaborate on this further? I don't see how HFTs make money at the expense of mainstreet investors. HFTs make money on the expense of inefficiencies, therefore making the markets more efficient.

I'd wager that without hfts liquidity would be just fine. Maybe smaller stocks wouldn't become the battleground for hft algos, but aside from that they're mostly penny skimming vultures that create the illusion of liquidity as they hop in and out of stuff at fractions of a second.

HFTs turn off their algorithms when the market gets particularly volatile and the liquidity vanishes at the moment it's actually needed.

Idk I think technological progress/humanity would do a lot better in general without the parasitic effects of people making the markets/trading their "job".

If someone writes some software, or grows some food, or balances some accounts, or paints a wall, they are all being endlessly more productive than someone who buys on a low and sells on a high and pockets the difference all within 100ms.

Investment means support and confidence in a venture or resource. I think a lot of the financial industry's problems arise from the switch from "investment in business x because I like what they're doing and am confident they'll succeed" to the mantra of "investment in business x because I don't actually care about the company but the stock history tells me I can make a quick buck". Market stability is a thing of the past, no wonder we're constantly on the edge of a recession.

Have you ever listened to an earnings call? It only takes a few words from CEO or CFO to reduce the value of the traded stock to nearly zero.

So in that scenario, is it beneficial to society that someone who has a 50ms delay live feed can unload their shares at a higher price than someone with a 5s delay live feed? Or the same question for someone who has AI to parse the information and execute trades faster than the human?

There's a benefit to liquidity to everyone, but I don't really see a liquidity benefit faster than a few _minutes_, much less faster than a few _ms_: end individual traders don't even get to trade that fast anyway, they're just artificially disadvantaged against the institutions.

Earnings call is a review of the quarterly earnings document usually released earlier that day. The stonk price fluctuates almost entirely on how accurate the guidance was and what the future guidance is. Even doing excessively good in a quarter can have a negative impact because they didn't give their investors an accurate heads up. I guess maybe some horrible pro-Hitler rant may affect the price, but to zero? I haven't seen that.

Don't believe the ionosphere has any role in any sort of radiation absorption, outside of RF?

The 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.

Why would O3 be damaged by H2O? SpaceX rockets are powered by hydrogen and oxygen and produce water as exhaust.

Kerosene 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.