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Submission + - The Gravity of the Situation (earth.com)

jd writes: A number of sites are reporting an unconfirmed breakdown of Relativity at extreme distance: Researchers have stumbled upon a phenomenon that could rewrite our understanding of the universe’s gravitational forces. Known as the “cosmic glitch,” this discovery highlights anomalies in gravity’s behavior on an immense scale, challenging the established norms set by Albert Einstein’s theory of general relativity. However, when applied to the vast scales of galaxy clusters and beyond, this model begins to show cracks. Robin Wen is the project’s lead author and a recent graduate in Mathematical Physics from the University of Waterloo. “At these colossal distances, general relativity starts to deviate from what we observe. It’s as if gravity’s influence weakens by about one percent when dealing with distances spanning billions of light years,” explained Wen. Here's the research paper causing the excitement: https://iopscience.iop.org/article/10.1088/1475-7516/2024/03/045

This is where it's being covered by the press: https://www.earth.com/news/cos... https://www.space.com/cosmic-g... https://phys.org/news/2024-05-... https://www.sciencedaily.com/r... https://uwaterloo.ca/math/news... https://www.newsweek.com/gravi... https://timesofindia.indiatime...

Comment Re:Never enough houses (Score 3, Insightful) 135

Italy and Japan have shrinking populations. We would too, if it weren't for immigration. However our population growth rate is still low, and if it were any lower we'd be facing serious economic and social challenges. Sure, a shrinking population would drop housing prices, but we are far from having so many people there isn't space to fit them. Our real problem is seventy years of public policy aimed at the elimination of "slums" and the prevention of their reemergence.

If you think about it, "slum" is just a derogatory word for a neighborhood with a high concentration of very affordable housing. Basically policy has by design eliminated the most affordable tier of housing, which eliminates downward price pressure on higher tiers of housing. Today in my city a median studio apartment cost $2800; by the old 1/5 of income rule that means you'd need an income of $168k. Of course the rule now is 30% of income, so to afford a studio apartment you need "only" 112k of income. So essentially there is no affordable housing at all in the city, even for young middle class workers. There is, however a glut of *luxury* housing.

In a way, this is what we set out to accomplish: a city where the only concentrations of people allowed are wealthy people. We didn't really think it through; we acted as if poor to middle income people would just disappear. In reality two things happened. First they got pushed further and further into the suburbs, sparking backlash by residents concerned with property values. And a lot of people, even middle-class young people, end up in illegal off-the-book apartments in spaces like old warehouses and industrial spaces.

Comment Re:Free Market (Score 1) 185

Trump is winning because of votes from people living in trailer parks, not because of donations from Wall Street. DeSantis wants to be the next Trump.

There's a lot of mythology around who Trump voters are. Part of it is that statistics can be confusing, especially if you're prone to jump to conclusions. Yes Trump wins the voters without a college degree, and people without college degrees tend to make less money, but we can't leap to the conculsion that Trump voters are poor. In fact, data shows Trump lost the $50k and under income group solidly in both 2016 and 2020. In 2016 he won every income group greater than $50k, although only *strongly* in the $50k -$99k group. In 2020 he solidly lost every income group betlow $100k, but but won the over $100k group by an enormous 12 point margin.

Putting it all together, Trump's core voter group are people with limited educational attainment who are economically comfortable of (good for them) well off without having a college degree. However he doesn't own any particular socioeconomic group; really elections are determined by changes in turnout in key swing states. There was strong turnout among Trump's *share* of $50-$99 ke voters in 2016; I don't think many of those voters changed their mind, but their compatriots who sat 2016 out came out to vote in 2020.

Comment Re:Who knows.. (Score 1) 185

Just because the cigarette industry pictured doctors recommending smoking in its advertising didn't mean that *all* doctors, or even most thought smoking was healthy for you. This was largely in the 30s and 40s when they took advantage of a positive attitude toward science and particular medical science. They began to pull back from this after 1950 when evidence was mounting for the link between smoking and cancer, for fear of pushback from the medical community.

Comment Re:My first programming language (Score 1) 106

Before any of us even imagined we'd have a computer or a course on it, we "programmed" in text books. The language was mostly GOTO, but might even have the occasional conditional as in, "If you like cheese turn to page 56 otherwise 103". Typical applications were insulting the teacher's appearance, as in "for a picture of the teacher, turn to page 45", where there was a picture of a gorilla.

This was of course, not permitted which made us low-key black hat "hackers". In private school the penalty for this was far too steep. I don't know if public school kids learned how to diagram sentences or not; but we did. I later realized we had been taught parse trees by another name.

Yes, BASIC was my first programming language on an actual computer.

Comment Re:student loans are big bucks for the banks! (Score 2) 250

More to the point, they're *guaranteed* bucks.

People don't understand the significance of risk to profitability. By underwriting 80 billion dollars of risk for banks, it's essentially guaranteeing them profits. When it's politically infeasible to spend money on something, the government guarantees loans. That's politically popular across the board because it's spending *later* money and it puts money in bankers' pockets.

Comment Re:More nuclear fission power plants? (Score 1) 37

To be clear, I think nuclear can and should play a key role in our response to anthropogenic global warming. I just think we shouldn't (a) talk about it like it is *the* answer in and of itself and (b) misunderstand the full breadths of risks and challenges, the most difficult of which are likely to be economic rather than political objections by environmentalists.

Ss you point out, climate change is in effect an economic externality that fossil fuels get a free ride on. This is a key reason for nuclear power's economic non-competitiveness -- in effect fossil fuel use is subsidized by future generations. If you made fossil fuel users pay the true cost of their energy use, nuclear would *instantly* become competitive. But politically that's not going to happen. The only politically possible way around that is to subsidize other energy sources as well.

If you haven't seen any nuclear advocates claim that we should stop investing in renewables, you haven't been paying attention. Usually they come out in response to some article on climate change or perhaps renewables and they will trot out the bogus argument that environmentalists killed nuclear, which is (they say) the only solution to climate change.

The argument that a particular technology is a panacaea isn't confined to nuclear advocates; I think renewable advocates oversell what's possible in the near future, just as anti-renewable people -- and yes, they exist if you're paying attention -- exaggerate renewables' limitations. Really any all-eggs-in-one-basket approach is unnecessarily risky and likely more costly than having several approachs that can work together and compete economically. Key to making that happen will be improvements in grid infrastructure, which will increase the size and therefore the efficiency of the energy market, allowing multiple sources of power to compete.

As for thorium, that's something we'll have to turn to if fission remains a long-term part of our energy supply, but it's not really a help in the time frame we have to respond to climate change. I think the most promising developments are in the development of fail safe reactor technologies and small modular reactors. There are such things as both economies of scale and *dis*-economies of scale, and SMRs are a different way of scaling production than the traditional and every expensive nuclear power plant.

Comment Re:Temperature Conversions ... (Score 3, Interesting) 37

And if you haven't experienced these temperatures you need to understand that those not accustomed to them can't do much of anything when it's that hot. I've experienced close to the higher of these two temperatures in Death Valley, and mild exertion was not sustainable. It was life threatening without an air conditioned car to get back to. The lower of these comps to being in my house when there was no air conditioning. What happens after a while is you're just consumed with keeping cool and can't focus on much else. A spray bottle and a fan helps a little, but if you're not wet and the air isn't dry, then there's a point where the fan stops acting to cool you and actually heats you up--it's a low-grade convection oven effect.

Motorcyclists are aware of this, they even have a chart out there somewhere that shows the break-even point where the wind stops cooling you and starts baking... but dang, all the links that I could find easily are badly enshittified. Just trust me, bikers will feel slightly *warmer* when riding at highway speeds in temperatures above 95F.

Some people can actually acclimate to these temperatures. They generally know who they are. The body is an amazing thing, but I'm sure even those people have their limits.

Comment Re:More nuclear fission power plants? (Score 3, Interesting) 37

It was never the case that the public being scared caused nuclear to be outlawed, or even *discouraged*. The problem is that investors are scared by the high capital costs, long construction times, and uncertainties about future electricity prices.

This is why nuclear requires government subsidies, either in straight grants, loan guarantees or price guarantees. It's no coincidence that the only country in the world that did a serious nuclear crash program was France, where the electric system was *nationalized*. They didn't go in big for nuclear to make a profit, for them it was a national security issue in result of the OPEC oil embargos. As soon as France privatized its electric system, nuclear construction stalled, just like it did in every other privatized system.

In any case, even if we *were* to underwrite a crash nuclear program, it's neither necessary nor desirable to put *all* our eggs in the nuclear basket. One place we can put investment in is a modernized grid. This will not only help renewable sources like wind and solar, it will be a huge boon to nuclear plants, eliminating questionable siting choices that were driven by the need to locate the plant within 50 miles of customers.

Comment Re:Ah yes, cheap batteries (Score 1) 100

The norm thirty years ago for a hardware store battery was zinc-carbon, with premium batteries being alkaline. The norm today is alkaline, with fancy batteries having a lithium chemistry. So it's absolutely true that the "regular AA" battery you put in your flashlight back then had something like an 800 mah capacity; there is nothing on the market today that is that weak.

In any case that's primary cells, which have zero relevance to this topic. We're mainly interested in secondary cells, and there the improvements in the common rechargeable battery has been dramatic and continual. Thirty years ago the standard hardware store rechargeable was Ni-Cad; a AA probably had about 700 mah capacity. A modern alkaline AA has a capacity of 2000 mah or so roughly 3x as much. This understates the case because modern rechargeable alkalines can typically be recharged easily twice as much as a 1990s NiCad. And *rechargeable* alkalines are getting significantly better almost year to year.

Of course the hardware store battery only has minimal relevance to what we're talking about. What we really care about is Li-ion, and capacity, lifespan and cost for *those* are improving faster than any other battery technology ever has.

Comment Re:EV will never overtatake hydrogen (Score 1) 131

Nope. Fleet operators can safely maintain a bank of charged batteries and swap them. Five minute operation or less with a properly designed truck. That's based on commonly used technology that exists, with peak storage batteries on the grid already. You can find plenty of qualified technicians to deal with all that. It fits in neatly with various industrial operations that might have other reasons to maintain a bank of batteries in order to smooth out their power consumption and get better electric rates.

H2 can sort of do all that--but needs high pressure tanks, and a way to convert to/from electricity but the real nail in the coffin is finding qualified technicians, and safely and quickly fueling the vehicles.

Hydrogen is a boondoggle pretty much every where. It made sense in some space craft, that's about it.

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