Interesting, I have the opposite opinion. I'm considering switching from Windows to the KDE Plasma desktop and so far I'm impressed with it. Plasma is the first Linux desktop I've used that feels polished and professional. It is more customizable than Windows is. I'm looking to avoid Win 11 with its telemetry, background downloads, advertisements, OneDrive problems, etc.
On the MENSA IQ test GPT-Pro got 34 out 35 correct for an IQ of 148. Very good. Rumor has it the one question it missed had something to do with instances of "b" in "blueberry."
20 year old cars tend to be heavy polluters because they don't meet the latest emissions standards. Here in California the state will buy old cars and scrap them to get dirty emitters out of service. Also, nearly every day electrical generation is over 50% using solar, wind or hydro so EVs are cleaner here than any ICE vehicle by far.
Well my 20 year old car meets the various clean air zone emission standards that newer cars fail to
However even if it didn’t, if I used it for 200 miles a year would it make sense to buy a new electric car?
It’s never clear cut, and it’s practically impossible to make the best decision in any given case. You can make a regulation which will on aggregate lead to less damage but there will always be exceptions, and on a case by case basis it’s extremely difficult to measure the damage a given scenario applies. How many “units of badness” does buying a new 2 ton electric car before you move it a single mile. Id wager it’s more than an existing petrol car burning 1 litre of unleaded petrol on existing tyres and brake discs.
The difficulty is measuring total impact of the choice. Sure buying a new petrol car and driving 20k miles a year for 6 years will be worse than buying a new electric car and driving 20k miles a year for 6 years. That’s not where the line is.
That 1985 Toyota emits more GHG and NOx per mile than a new vehicle because it wasn't built to meet the latest US or Canadian emissions standards. Older vehicles emit more pollutants so in some US states the government will buy the car to have it scrapped, thus improving the overall fleet emissions statewide. In California there are owners who keep and maintain pre-1975 vehicles because they have little or no smog control systems, are easy to work on, and they are exempt from mandatory bi-annual smog testing.
Investigation might not be complete, they could add an espionage charge later. Depending on what US code section they charge him with it could be up to 10 yrs, 30 yrs or life.
It irks me so many physicists/cosmologists jump from the mathematical GR singularity at the center of a BH to "matter there has infinite density." That's highly unlikely, it's probably quark plasma.
My simple model of it is to just think about spatial surfaces and do "accounting" of the total flux through them.
If you draw a sphere around a star collapsing into a black hole, you can treat it as a closed system. If the black hole evaporates, then all of the mass-energy of its progenitor original star needs to leave through these concentric surfaces. This is on the same order of magnitude as a supernova, as it is equal to the collapsed core of the star being converted into pure radiated energy!
An infalling observer accounting of the mass-energy flows must match this external view point. As they cross smaller and smaller bounding spheres, they must see this energy flowing out through those boundaries, adding up to the same total. (There is nowhere else for the energy to go; it has to be blasting you in the face as you fall in!)
Oversimplified models of black holes concentrate the mass-energy to a point, leaving spacetime around it an empty vacuum. So an infalling observer will see zero, zero, zero, zero... infinite energy density for an infinitesimal time. This is non-physical nonsense, and isn't even mathematically sound!
From Hawking we know that infalling (and distant) observers see some finite energy flux, and from Einstein's GR we know that infalling observers will see this blue-shifted and time-accelerated on the way in.
The logical conclusion is that the flux is observed to increase smoothly by infalling observers until the entire amount is accounted for in a finite time. This is a staggering total amount of radiated energy, equivalent to an matter/anti-matter explosion of matter the density of a neutron star core! There is no way anything could "fall through" this while jotting down their observations. It's not a survivable journey.
There are no wormholes, reachable parallel universes, and there are no separate white holes "elsewhere" in the universe. A black hole is the white hole, smeared out trillions of years into the future so that the enormous total energy is radiated out so slowly from an outside perspective that they just look black. Infalling observers see the "true" white nature of these explosions frozen in time.
> If you draw a sphere around a star collapsing into a black hole, you can treat it as a closed system. If the black hole evaporates, then all of the mass-energy of its progenitor original star needs to leave through these concentric surfaces.
That would be great if energy were a conserved quantity in General Relativity, which it isn't. Heck, we don't even know how to write down the total energy/momentum of a given spacetime volume.
That's incorrect. Energy conservation can be violated at a much smaller scale, e.g. when gravitational waves are involved, or redshift phenomena (e.g. in Schwarzschild).
Yes, we usually talk about the fact that gravitational waves can carry energy but what exactly is their energy content? And what exactly is the conservation equation here?
> Locally GR conserves energy the same as any other self-consistent physical theory.
Locally, you can write down a divergence equation for the energy momentum tensor, yes. However, locally we're in Minkowski space anyway, so that is not really surprising.
The point is that the local divergence equation doesn't take into account the energy carried by the gravitational field itself. To give another example beyond gravitational waves: A Schwarzschild black hole carries mass, even though it is a vacuum solution to the Einstein field equations.
From what I understand of it the singularity is analogous to what happens in the 2D Cartesian plane with functions such as f(x) = 1/x. When x equals 0, the function itself "breaks down" because the y-coordinate extends to infinity (ie f(0) is "undefined"). In the context of a black hole that means that neither time nor space (hence neither does matter) "exist" at this singularity. In other words upon arrival the falling object has essentially "reached the end of time".
The Starlink satellites have a design lifespan of about 5 years and will reenter the atmosphere relatively quickly even if not actively maneuvering, simply by virtue of being so close to Earth.
Yes, and battery storage is why California got through a severe heat wave in July without rolling blackouts or major outages. There wasn't even a FlexAlert. Batteries time-shifted excess solar power from noon to the early evening, when air conditioning demand is at its highest.
