Alternative theories of gravity are like alternative theories of medicine, they tend to be thoroughly invalidated and none are anywhere near as effective as the mainstream theory. As the wiki article you linked notes:
However, such models are no longer regarded as viable theories within the mainstream scientific community and general relativity is now the standard model to describe gravitation without the use of actions at a distance.
General relativitiy is one of the most tested, validated theories in physics. It is incredibly successful, not just describing the attraction of massive bodies but also describing frame dragging (solving a longstanding mystery on the retrograde motion of Mercury that Newtonian gravitation couldn’t explain), and predicting gravitational lensing and gravitational waves, both of which have been observed since and are perfectly described by GR.
An alternate model should attempt to solve a problem in the current leading one, for example giving a more fundamental explanation, or working at different scales where the current model fails (quantum gravity theories, for example). A good alternative model will also give results that are consistent with all existing observations, which is one area that every alternative theory of gravity I’m aware of fails. What problems in GR are you looking to resolve with an alternate gravitational model?
I’m not interested in questioning Einstein’s gravity - it’s super successful. I was interested in the history and alternative ideas that beaches out and died and the Wiki did have some decent info and even papers on “ether.” Fascinating and maybe intuitive for its time. It’s very hard to find any writing on postulating the mechanics that cause gravity to warp space/time. I was mostly interested in finding if there was some kind of wave function (not a graviton) within to describe the, “why.” There’s so much energy within atoms that you’d think there was more than enough room for hypotheticals, but none that are famous enough to discover on the Internet.
I suppose the elements formed by fusion of hydrogen are pretty fixed. It’s mostly helium. Only the rate depends on the pressure and temperature of the fuel.
So I don’t know whether fusion happens in an accretion disk. But if it does, the elements formed are mostly helium, and a few other light elements at trace amounts.
Hi! Googling this question reveals the answer is yes, it does result in fusion.
As far as the output, according to this top result paper, that depends heavily on the size of the black hole, the size and speed of the accretion disk, and the medium from which the black hole is drawing (like a white dwarf vs interstellar gas).
From what I can make out–and I have no background–the author maps out results as high in weight as nickel.
This post on physics.stackexchange.com claims that hot accretion disks can reach 10^12^ K, hot enough for fusion to occur but not at rates that would make fusion a significant source of radiation from the disk.
Oh shit good question. I’m gonna say no because I was really trying to ask about how much ice/water/dust is involved, but I’m also curious about the air.
Researchers at the US National Centre for Atmospheric Research calculated the density of a cumulus cloud to be around 0.5 grams (0.018 ounces) of water per cubic meter, so a 1 cubic kilometer (0.24 cubic mile) wide cloud would contain 1 billion cubic meters (35 million cubic feet). If you calculate the number of cubic meters times by the density, 1,000,000,000 x 0.5, you’ll be left with the total weight of a cumulus cloud of that size – 500,000 kilograms (1.1 million pounds).
I think the term “weight” - while useful at sea level - can easily confuse people when it comes to clouds, as the density of the water in a cloud doesn’t have much to do with the weight of the cloud - see my elaborated edited response (unless I mis-guesstimated) - the mass of a cloud changes so drastically with altitude that the relative or even the absolute weight of water (vapor) therein is going to give people the wrong idea.
I think you’d be better served to ask about the average volume of a cloud (if that makes sense, given how diverse they come). Because the mass is pretty much exactly volume multiplied with density. And the average density of clouds is pretty much exactly that of the surrounding air at the given altitude (because otherwise the cloud would not float, but either rise up or sink down). And the density of air at any given altitude is given by the Barometric formula. If you take a kubik kilometer of cloud (honestly, I have no idea how big clouds are), it would have a mass of approximately 364 thousand tons at 11 km above sea level, 88 thousand tons at 20 kilometers above sea level, 860 tons at 51 km above sea level and ca. 64 tons at 71km above sea level. But “regular” clouds only go up to ca. 20km, and 95% of the clouds you see are probably below 8km. Unfortunately the quoted wikipedia page has no entry for the barometric pressure at that altitude and I am too lazy to try and calculate it right now ;)
Ever seen a cloud form out of clear air, or burn away to nothing?
The thing is, all the water that makes a cloud visible is still in the air even when you can’t see it—it’s a combination of temperature and pressure changes that cause invisible water vapor to condense into visible water droplets. So you could be looking at a clear sky on a warm day that actually holds a greater mass of water than a sky full of clouds on a cold day.
My (flawed) understanding is the innermost rings of the accretion disk spin around the event horizon at nearly the speed of light, and it is friction (that is material collisions) that raise temperatures so high. So when a bunch of mass (say, a rogue asteroid) falls towards a black hole, it gets broken down and spaghettified by tidal forces and then combines into the accretion disk. As it moves towards the center, the friction creates a lot of light and heat which we can detect, and have called a quasar (a quasi-stellar object).
So it sure seems to fit all the parameters that make fusion likely. I can’t say if we’ve ever detected fusion within a quasar event.
With even a small increase in uncertainty in electron position, electricity would start to behave differently. Everything electronic, which depends on electron flow through very tiny conductors, would become unreliable as the electron flow would be unpredictable. Even basic light bulbs probably wouldn’t work.
Chemistry is the exchange of electrons between atoms. All molecular bonds happen through the exchange of electrons from one atom to another… so an increase in uncertainty would result in the bonds breaking down. Molecules would break apart, every material you think of as solid would disintegrate into its base atoms.
So, your rolling ball would cease to be a cohesive ball, and the surface it is rolling on would also cease to be.
Real life quantum physicist here. When you say you want the uncertainty principle to be bigger, what you are really saying is you want Planck’s constant to be a bigger number. This has much bigger consequences than you might expect, because if nothing else about the universe changes (for example Coulomb’s constant) then the energy levels of atomic transitions all get out of whack, you break chemistry and chemical bonding, and there is no such thing as a basketball because there are no such thing as rubber molecules.
A good way of exposing this idea to people is showing them the step by step of how to get the particle in the box energy equation and then generalizing it for 3d.
It becomes really obvious the issues that happen when you have degenerate states.
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