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.

Your comment has nothing to do with the fact that mass is explicitly part of the source term in Einstein's field equations.

The belief that mass is not a source term for gravity is absurd, and also non-physical.

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).

Best isn't the question. Sales is the question. If you do a poll of photographers, the names you'll hear when you ask what they shoot with are almost always going to be Lexar and SanDisk. Sony won't be in the top five. IMO, that's mostly because they spent a decade with their own Memory Stick nonsense while other manufacturers were claiming the SD and CF card market for themselves. It's hard to force your way into an already crowded field where everyone has already picked favorites.

Yeah, but approximately nobody uses CFExpress. It was an attempt by the CompactFlash folks to stay relevant after the SD card standard ate their lunch. No still camera I've never owned, nor any camcorders (including fairly high-end 4K gear from major manufacturers) uses it. Everybody uses SD. Even most cinema cameras (which as far as I'm aware, are approximately the only gear that *ever* used CFExpress) mostly use SD cards now, or else have removable backs with SATA SSDs or similar.

Put another way, today I learned that somebody still actually made CFExpress cards. I thought the standard was thoroughly and completely stillborn. This is a tiny niche of a niche. And saying that Sony is price-comparable on something that is so niche that it is compatible with only maybe a dozen cinema camera models built by two or three companies within a narrow range of years doesn't exactly contradict what I said about suspecting that nobody uses them because of the cost. I doubt any other CFExpress cards are affordable, either, because economies of scale basically don't exist for a product that's so low-volume.

When I go to buy SD cards — and yes, at this point, almost everybody uses SD cards — I'm not even looking at products made by Sony. I'm looking at products by SanDisk and Lexar. I would be okay with Kingston or Transcend in a pinch. I guess some folks also like Samsung, though I've been burned by other Samsung gear often enough that I don't trust them with something critical like an SD card. Sony isn't even on my list. And pretty much every photographer and videographer I know does the same.

Given that Sony screwed around for more than a decade with their own proprietary "Memory Stick" format, they basically missed the market for SD cards, and other companies claimed that market.

Based on that, at least in my mind, I kind of assume that the people who buy Sony flash cards are probably the ones who have always bought Sony, because it's the only name they know and trust. Most of those folks probably started on Sony back in the 1970s when their products were actually built to last for decades, were top-tier in features, rather than being hobbled by pressure from their entertainment division, and when repair parts weren't priced so high that a power switch costs more than a whole new camcorder (not kidding). They're probably the ones who used to buy overpriced Sony headphones for $150 that fell apart instead of the $50 Koss headphones that didn't. They're also probably the ones who still have analog land line home phones, and most of them are probably retired or dead by now.

*Maybe* some of their mirrorless camera purchasers from the last few years buy Sony cards out of some bizarre sense of brand loyalty, but I'd imagine most of them talk to other photographers and ask what to buy, and again, I'm pretty sure Sony won't be on anybody's list.

I'm just struggling to imagine them having much of a market except perhaps in niche products like CFExpress or in cheap CF cards sold at Walgreens or CVS for high margins to people who don't know any better.

But maybe I'm wrong.

No, they would only consolidate their product line if they thought that doing so would make it more profitable. That would require a high enough volume of sales to matter. Companies don't usually cut entire swaths of products because of the price point. They usually do it because the product line makes so little money that it isn't worth the extra effort to keep it going.

Maybe in the book. In the movie there is no science.

Although I don't think I can come up with ANY plausible explanation for the magical bugs.

Seriously? What's with these money grubbing people. Every month they come out and say everything is causing brain fry.

When can we push back and say "STOP SAYING BULLSHIT"?!

WHEN????

Sony has this tendency to sell overpriced hardware. Could it be that nobody was buying Sony's SD cards?

It is popular throughout the world with many millions of installs. Half the country (USA) has legislation allowing balcony either already on the books or in process.

With a unidirectional meter you can have counting of reverse flow be blocked or count as an absolute value of flow against you. I don't know the details about models and reasons for it yet I know people with these meters have been charged for unintentional export because they for example had the CT installed backwards.

Which is also mass density. Multiply by c to keep the units straight. (If you're a physicist, you just set c=1, and the units don't matter.)

I guarantee, if you have a mass density of M kg/m3 and you put it in Einstein's field equations, you get gravitation.

What we really need are proper support systems for children in place, but in the real world they often don't exist. Some parents also seem to think they should have full control over their children and know everything they are doing at all times, which makes things like seeking support for being LGBTQ bother difficult for the child and something that the parents demand is not made available.

Maybe we could set up better moderated communities for this kind of thing, but that brings its own problems. As an example, with the current attacks on trans healthcare in the UK, a lot of trans kids are being forced to go the "DIY" route for treatment. It's not illegal as such, but it is something of a grey area. Any kind of official moderation is likely to make such forums useless to a lot of people.

Are you sure you were paying attention when you read it, because that's not what happens in the book. For example, Rocky needs essentially an environmental suit to survive in an atmosphere suitable for humans, due to his planet having much higher pressure and temperature. Communication is established over some time based on engineering principles, which are universal properties of the universe and a classic sci-fi trope for communicating with very different alien species.

I thought it was a pretty good book overall. Lots of interesting ideas and detail. Strong characters, at least for the protagonist and Rocky.