You're confusing the importance of avoiding Kessler syndrome in LEO with the difficulty of causing Kessler syndrome. GEO debris can potentially remain there for millions of years before interactions between the gravitational pull of the Sun, Earth, and Moon sufficiently perturb it. LEO debris remains for weeks to months. You have to have many orders of magnitude more debris in LEO to trigger Kessler Syndrome, where the rate of collisions exceeds the rate of debris loss.

The fact that a LEO Kessler Syndrome would also be short is something that exists on top of that.

It's also worth nothing that not only are modern satellites not only vastly better at properly disposing of themselves than they were in the 1970s when Kessler Syndrome was proposed, but they're also vastly better at avoiding debris strikes. All of these factors are multiplicative together.

Lol, I was thinking of this instead ;)

People forget that the primary concerns about Kessler Syndrome were about geosynchronous orbit, which used to be where all the most important satellites went (many of course still go there, but not the megaconstellations). It takes a long, long time for debris to leave GEO. But LEO is a very different beast.

They said it's internal rather than a collision, so probably a failed COPV would be my guess.

Yeah. In particular:

with fragments likely to fall to Earth over the next few weeks

LEO FTW. Kessler Syndrome is primarily a risk if you put too much stuff with too poor of an end-of-life disposal rate in GEO. End-of-life without proper disposal rates have declined exponentially since Kessler Syndrome was first proposed (manufacturers both understand the importance more, and do a better job, of decreasing the rate of failures before deorbit - in the past, sometimes there wasn't even attempts to dispose of a craft at end-of-life). And now we're increasingly putting stuff in LEO, where debris falls out of orbit relatively quickly. It's not impossible in LEO, esp. with higher LEO orbits - but it's much more difficult.

Or to put it another way: fragments can't build up to hit other things if they're gone after just a couple weeks.

And this trend is likely to continue - a lower percentage of premature failures, and decreasing altitudes / reentry times. Concerning ever-decreasing altitudes, we've already been doing this via use of ion engines to provide more reboost (with mission lifespans designed for only several years before running out of propellant, instead of decades like the giant GEO ones), but there's an increasing interest in "sky skimming" satellites that function in a way somewhat reminiscent of a ramjet - instead of krypton or xenon as the propellant for an ion engine, the sparse atmospheric air itself is the propellant, so the craft can in effect fly indefinitely until it fails, wherein it quite rapidly enters the denser atmosphere and burns up.

ED: "But it doesn't work for gravity with linear curvature"

Relativity = gravity is represented by the curvature of spacetime. Curvature is linear, R. The formula treats curvature linearly. As things get closer and curvature spikes, the math just scales at a 1:1 rate

Quadratic gravity = Squares the curvature. Doesn't really change things much when everything is far apart, but heavily changes things when everything is close together.

Pros: prevents infinities and other problems when trying to reconcile quantum theory with relativity ("makes the theory renormalizable"). E.g. you don't want to calculate "if I add up the probabilities of all of these possible routes to some specific event, what are the odds that it happens?" -> "Infinity percent odds". That's... a problem. Renormalization is a trick for electromagnetism that prevents this by letting the infinities cancel out. But it doesn't work with linear curvature - gravitons carry energy, which creates gravity, which carries more energy... it explodes, and renormalization attempts just create new infinities. But it does work with quadratic curvature - it weakens high-energy interactions and allows for convergence.

Cons: Creates "ghosts" (particles with negative energies or negative probabilities, which create their own problems). There's various proposed solutions, but none that's really a "eureka!" moment. Generally along the lines of "they exist but are purely virtual and don't interact", "they exist but they're so massive that they decay before they can interact with the universe", "they don't exist, we're just using the math out of bounds and need a different representation of the same", "If we don't stop at R^2 but also add in R^3, R^4, ... on to infinity, then they go away". Etc.

The theory isn't new, BTW. The idea is from 1918 (just a few years after Einstein's theory of General Relativity was published), and the work that led to the "Pros" above is from 1977.

In short, Java was invented for a reason, and while it has become a victim of legacy cruft as well, the underlying concept of truly portable apps, with a minimum of fuss to jump from platform to platform, still ought to be the preferable path. The problem is that that true platform neutrality/ambiguity pretty much kills Microsoft in all but a few niches, like gaming, but only because hardware vendors put less effort into drivers for other operating systems.

Yes, Office is still king, although I think that crown is beginning to slip, and it may end up being Excel, with its large list of features, that may last the longest. But it isn't 1990, or even 2000 anymore. Developers have multiple ways of developing portable applications, and while MS may (for the nth time) update or swap out its toolchains, the real question is will developers really care?

A bit more about the latter. Beyond organophosphates, the main other alternative is pyrethroids. These are highly toxic to aquatic life, and they're contact poisons to pollinators just landing on the surface (some anti-insect clothing is soaked in pyrethrin for its effect). Also, neonicotinoids are often applied as seed coatings (which are taken up and spread through the plant), which primarily just affect the plant itself. Alternatives are commonly foliar sprays. This means drift to non-target impacts as well, such as in your shelterbelts, private gardens, neighbors' homes, etc. You also have to use far higher total pesticide quantities with foliar sprays instead of systematics, which not only drift, but also wash off, etc. Neonicotinoids can impact floral visitors, with adverse sublethal impacts but e.g. large pyrethroid sprayings can cause massive immediate fatal knockdown events of whole populations of pollinators.

Regrettable substitution is a real thing. We need to factor it in better. And that applies to nanoplastics as well.

So, when we say microplastics, we really mainly mean nanoplastics - the stuff made from, say, drinking hot liquids from low-melting-point plastic containers. And yeah, they very much look like a problem. The strongest evidence is for cardiovascular disease. The 2024 NEJM study for example found that for patients with above-threshold levels of nanoplastics in cartoid artery plaque were 4,5x more likely to suffer from a heart attack. Neurologically, they cross the brain-blood barrier (and quite quickly). A 2023 study found that they cause alpha-synuclein to misfold and clump together, a halmark of Parkinsons and various kinds of dementia. broadly, they're associated with oxidative stress, neuroinflammation, protein aggregation, and neurotransmitter alterations. Oxidative stress is due to cells struggling to break down nanoplastics in them. They're also associated with immunotoxicity, inflammatory bowel disease, and reproductive dysfunction, including elevating inflammatory markers, impairing sperm quality, and modulating the tumor microenvironment. With respect to reproduction, they're also associated with epigenetic dysregulation, which can lead to heritable changes.

And here's one of the things that get me - and let me briefly switch to a different topic before looping back. All over, there's a rush to ban polycarbonate due to concerns over a degradation product (bisphenol-A), because it's (very weakly) estrogenic. But typical effective estrogenic activity from typical levels of bisphenol-A are orders of magnitude lower than that of phytoestrogens in food and supplements; bisphenol-A is just too rare to exert much impact. Phytoestrogens have way better PR than bisphenol-A, and people spend money buying products specifically to consume more of them. Some arguments against bisphenol-A focus on what type of estrogenic activity it can promote (more proliferative activity), but that falls apart given that different phytoestrogens span the whole gamut of types of activation. Earlier research arguing for an association with estrogen-linked cancer seems to have fallen apart in more recent studies. It does seem associated with PCOS, but it's hard to describe it as a causal association, because PCOS is associated with all sorts of things, including diet (which could change the exposure rate vs. non-PCOS populations) and significant hormonal changes (which could change the clearance rate of bisphenol-A vs. non-PCOS populations). In short, bisphenol-A from polycarbonate is not without concern, but the concern level seems like it should be much lower than with nanoplastics.

Why bring this up? Because polycarbonate is a low-nanoplastic-emitting material. It is a quite resilient, heat tolerant plastic, and thus - being much further from its glass transition temperature - is not particularly prone to shedding nanoplastics. By contrast, its replacements - polyethylene, polypropylene, polyethylene terephthate, etc - are highly associated with nanoplastic release, particularly with hot liquids. So by banning polycarbonate, we increase our exposure to nanoplastics, which are much better associated with actual harms. And unlike bisphenol-A, which is rapidly eliminated from the body, nanoplastics persist. You can't get rid of them. If some big harm is discovered with bisphenol-A that suddenly makes the risk picture seem much bigger than with nanoplastics, we can then just stop using it, and any further harm is gone. But we can't do that with nanoplastics.

People seriously need to think more about substitution risks when banning products. The EU in particular is bad about not considering it. Like, banning neonicotinoids and causing their replacement by organophosphates, etc isn't exactly some giant win. Whether it's a benefit to pollinators at all is very much up in the air, while it's almost certain that the substitution is more harmful for mammals such as ourselves (neonicotinoids have very low mammalian toxicity, unlike e.g. organophosphates, which are closely related to nerve agents).

While it is an enormous problem, possibly the most significant, we know how to shield against radiation, but it's going to take mass in the form of hydrogen-rich molecules like water or polyethylene (as examples). To solve that problem we are either going to have to make launches a lot cheaper, or figure out how to do it all in orbit.

It's at the edge of our technological capacity to produce such a spacecraft now, so the barrier is economic. That's a massive barrier, but in theory we definitely could, if we put a significant percentage of GDP of the wealthiest nations towards the project, produce a spacecraft that keep astronauts alive and relatively protected from ionizing radiation both on the journey and while on Mars.

As to your general assholery, I guess everyone has to have an outlet, though why Slashdot is a bit mysterious.

I hate all of this sales pressure BS - that the instant anyone hears your name you have to try to "convert" them to sales - and I literally run a webstore.

It's all so deeply anti-consumer, and I want no part in it.

This debate has been going on for at least a couple of decades. I remember back in the Usenet days, when AOL and other early ISP users first started showing up in droves with whacked out untraceable bang paths that people were trying to sort out technical solutions, usually involving some servers tarpitting some domains, with the inevitable consequence that valid users (by whatever definition any given Usenet group had) were blocked.

In a way, AI bots aren't any different than the spam problem on fax machines and email; universal low-barrier delivery meets large scale programmatic swill. AI allows complexity that earlier spambots couldn't dream of, when the most sophisticated way of defeating filters was spelling "porn" as "pr0n" and a bit of header fuckery. In the end there is only two ways to go; either do what filtering you can and accept some degree of false positives, or go to identification systems that will, one way or the other, compromise anonymity, because make no mistake, once you start storing any kind of data linking an account to an actual human being; biometric, picture ID, phone number, mailing address or whatever, it won't take long for the court order to show up demanding you hand over all the de-anonymized account data to find the person distributing child porn, drugs, or calling their local political representative dirty names.

Firstly, I see you have this notion that martian rocks must all be igneous.

You're not talking about rock, you're talking about regolith.

Depending on where the regolith is sourced

Regolith is not "sourced", it's blown across the whole planet. It's not simply "whatever the underlying strata is made out of".

But, since we are playing 'name the ignorance' in this exchange, your attestation stat perchlorate is 0.5% liberatable oxygen says 'Say i'm ignorant of basic chemistry without saying i'm ignorant of basic chemistry, and am bad at reading too.' The 0.5% statistic comes from the publication at bottom, and is the proportion of the regolith that is perchlorates.

I am the one who mentioned that regolith is 0.5% perchlorates, not that "perchlorates are 0.5% oxygen". *facepalm*

"Saying we'll get oxygen from the 0,5-1% of a poison in martian regolith, rather than bulk ice or CO2, is..."

For God's sake, learn to fucking read.

Washing the regolith to remove the perchlorate is a requirement for *any* other use of that regolith

Which is why you shouldn't be celebrating its existence. It is a problematic contaminant, not a resource.

As you have rightly pointed out, the water ice on mars is more 'frozen mud'. Cleaning the melt is going to be a necessary first step to using it *regardless*. That means either vacuum distillation, thermal distillation, or reverse osmosis filtration. Again, NOT OPTIONAL. This is necessary equipment that you need to bring, regardless.

And this just to get water, the most basic of offworld resources. And all of that equipment (especially the mining hardware itself) requires maintenance and spare parts, which impose more dependencies. And the TRL for use on Mars is low regardless.

You've gone from talking up the ease of operating on Mars to talking it down, yet your self-righteousness hasn't shifted at all in the process.

RO filtration is the least energy intensive of these.

Except, it isn't. 0,5-1% perchlorates. RO typically removes 90-95% of perchlorates. So you're down to ~500ppm. Human safety levels** are in the low parts per billion. You're five orders of magnitude off. Yes, you can purify water that far - and the more perchlorates, the easier - but you're talking an over millionfold reduction. It is not at all trivial. You're talking first RO to get it down to levels where it won't hinder bacterial growth, then bioreactor bacterial remediation, then filtration, then RO, then ion exchange. This is not some little, simple system.

** Plants can tolerate much more perchlorates than humans, but they also bioaccumulate perchlorates of exposed to them, so you have to reduce the water to low ppb levels.

The end products are clean water and perchlorate contaminated mud, and clean mud, with contaminated water.

Viola! *eyeroll*

And your "plan" for dealing with waste perchlorate doesn't just magically produce pure O2 and NaCl in the real world. First off, molten sodium perchlorate, which is what it becomes before it decomposes, is an extremely corrosive oxidizer. Exactly what are you planning to make the furnace out of, platinum? Secondly, you never get perfect decomposition. Apart from residual perchlorates, you have residual sodium chlorate, which is also corrosive, and is a literal herbicide. And your gas stream will contain contaminant chloride and chlorine dioxide, which, news flash, you don't want to breathe.

There is no way on Earth anyone would ever prefer this to just conducting electrolysis on the water that you've already purified.

Neo and Android-based Chromebooks, and "good-enough" Office alternatives like Google Docs and I would argue even LibreOffice (I use it almost exclusively these days), mean Microsoft is suffering a differentiation crisis. They'll likely have the corporate lock for some time to come, though they've managed to fuck up Outlook so badly that I have to be wondering if the only thing really keeping the big guys locked in as Teams at this point.

MS's ability to leverage Windows as the platform is decaying, and the "bells and whistles" approach has managed to alienate a lot of users. People are at the point where they use Windows because they have to, but there's enough platform-agnostic functionality out there that the old lock-ins they relied on to keep Windows dominant are becoming more like prisons for their own development teams.