MigL

The interval is the space-time distance between two events. The path-history of the sword is its worldline. Not necessarily the same.

Goats ??? I was thinking sacrificing virgins ...

Did not know that about Selenic acid. Thanks John.

Yeah. The people on the planet Lagash thought it was just the rantings of conspiracy theorists also ... Nightfall (Asimov novelette and novel) - Wikipedia

As the accurate measurement of the speed of gravitational waves, 5 years ago, ruled out any Modified Newtonian Dynamics theories that also require Dark Matter, and these results rule out MOND theories that don't require the addition of Dark Matter effects, I would think the last nail has been driven into the coffin of M Milgrom's theory.

Pure gold is resistant to all acids, except a mixture of Hydrochloric and Nitric, called Aqua Regia. I would think any mixture, or alloy, of gold would have its 'impurities' affected by other acids, so that might be a simple test ? sand off a few grains, and drop some readily available Hydrochloric or Sulfuric acid on them; see if you get any bubbling action.

Not sure about all of Europe, but Southern Europe, Italy in particular, is what I'm most familiar with, and house/building construction is mostly concrete/stone. In North America, at least for homes, it is mostly wood/insulation. One thing I found is that in the Summer's 35o temps, North American homes are brutally hot without air-conditioning, while Italian homes, with thick concrete walls, are actually quite comfortable. Then again, it could simply be the difference in humidity. I haven't much experience with European winters, but Southern Europe sees very mild winters, so a lot of places get by with fireplaces as opposed to central heating. ( however, that stone/concrete construction is a real bitch during an earthquake )

Was supposed to be clear skies in the Niagara Region allowing for three to four minutes viewing time, and the city of Niagara Falls has practically called a state of emergency due to the number of eclipse chasers/tourists expected. But now we're looking at better than even odds for cloudy skies. Then again, not like the weather forecasters haven't been wrong before. Keeping my fingers crossed.

Quote from Jurassic Park "Life will find a way ". The thing about life is that it adapts. Not to color of the parent star, but to the wavelength of highest intensity in the star's spectrum. Our sun, for example, emits a skewed bell shaped distribution of radiation, rising rapidly in the long wavelength region, peaking in the visible light wavelength, and trailing off gradually in the short wavelength region. It is no wonder that life on this planet evolved such that our eyes are most sensitive to visible light wavelengths, and that plants make use of the more abundant energy source at those same wavelengths. The skewed bell shaped intensity curve is called the characteristic black body radiation curve for the temperature of the emitting surface. For a blue/white star like Spica, the peak of its curve may be in the ultraviolet range, so life ( ? ) on a planet orbiting Spica, would not be adapting to a particular color, or chemical process, but would need to adapt to extreme amounts of UV radiation. Similarly, life on a planet orbiting a blue star like Rigel might have to adapt to even shorter wavelengths, not only UV, but also some amounts of x-rays, which would necessitate totally different chemical processes, as x-rays can ionize loosely bound electrons.

The Quantum Mechanical charge carriers in a semiconductor behave in non-deterministic ways, and we can model that with probability amplitude distributions. The transistors in the CPU and memory of the computer/phone you are posting with are essentially macroscopic and can be modelled with deterministic circuit theory. Both models, non-deterministic describing quantum particles, and deterministic describing circuit elements, give results accurate enough that the approx. 100 Billion transistors comprising CPU and memory of your device, run totally deterministic programs. Every single time ... no probability about it. Sometimes, even I find it amazing. So where is the contradiction ???

For myself, faith and religion, are not offensive ( as it may be to Moon ), because, although they lack any existential evidence, some people have a 'need' for them The delusion of faith, or religion, gives them peace of mind and relieves their fear of the unknown. I see no need to take a crutch away from an emotional cripple. So, while I have no need for it, I tolerate it. But when it starts getting 'in your face' with ridiculous garbage like 'revealed faith', most sensible people, and R Dawkins certainly is one, will push back. My respect for him has gone up even further. And by the way, didn't you guys ( Exchemist, Moon, Charon and JC ) read ... the OP only respects Physicists 😄😄 .

No, I totally agree with you when the discussion involves factual subjects, like vaccines or the shape of the Earth. But there are subjective opinion based discussions where the 'experts' don't agree with each other and sometimes make a mess of things. The soft sciences, psychiatry being one example, is where I would find issues with your approach. I remember examples, from a few years back, where people who suffered from emotional trauma, or delusions, were led, by their Psychiatrist, to 'remember' traumatic events from their childhood, such as emotional, physical, sexual or incestual, depending on the fashion of the week, that actually never happened. Who would you choose as 'experts' in a discussion about garbage such as 'revealed faith' ?

Perhaps it's a language issue, but you haven't explained what you find 'contradictory'. Any valid theory has to be self consistent, and the Big Bang theory, while it has gaps of understanding, is self-consistent. Since it was first proposed the gaps have been filled in by theory like particle Physics early universe nucleosynthesis and inflationary theory, and observation, like the temperature and smoothness of the CMB. Observation, however, is a 'two-sided sword', as it also reveals additional gaps, such as those revealed by James Webb telescopic observations. But the major gap, where we cannot make headway, is at extremely small separations, where early universe and Black Hole answers are hidden, because we cannot get anywhere near Planck scale observations, This realm is non-deterministic, and contrary to your hopes, the universe IS non-deterministic, while determinism is an emergent statistical property. Quantum mechanics/field theory will never be deterministic, and any future quantum gravity theory will, itself, be non-deterministic at small scales whilst approaching GR's geometrical interpretation at larger ones.

No, not you., Moon. The term 'revealed faith'.

As the Big Bang theory is an evolution of space-time, not a specific event, and it encompasses Inflationary theory. One of the reasons for Inflationary theories is the horizon problem. It arises because the only part of the universe we are in causal contact with, is the observable universe; so how did the parts outside the observable universe become homogeneous and isotropic ? At some time immediately after the initiation of the Big Bang, the universe had to have been in causal contact to allow light ( and information ) to cross the universe and establish an equilibrium . Inflation then provides many orders of magnitude expansion before settling down to its current rate, with the universe no longer in causal contact. Without the initial causal contact/equilibrium we would have a 'horizon problem', as we could not explain how the universe can be homogeneous and isotropic; inflation solves that problem.

How is that different from regular faith, Moon ? It just sounds much more 'pompous',

That the Earth is not flat is factual, and can be proven. That vaccinations are beneficial is also factual, and can also be proven. I stand by my claim that subjective opinions are NOT factual. Just like a rectum, everyone has one. And society decides which opinion is 'fashionable'; dissenting opinions only get you labelled, and the fashionable opinion 'du jour' must then be protected against the dissenting views. What the hell is 'revealed faith' anyway ? I may tolerate it,but I see no reason to protect such garbage.

Do you mean me ? I'm just trying to stir up a good discussion. ( almost managed to drag INow into it, unfortunately, I had to agree with him 😄 ) Are you saying that in the case of the OP, which references 'revealed faith' ( whatever that is ), discussion should be vetted by priests/rabbis/imans/etc. who have the actual 'expertise' ? I can see that working out really, really well ... I agree that universities are in a tough position, but fact based information cannot be easily dismissed. Opinion based information is a different matter; who is the arbiter of what is valid discussion, and what is conspiracy theory 'sucking all the oxygen from the discussion' ?

That video you posted is not PBS Spacetime, which can be a little speculative, but does an excellent job of explaining mathematical theory in terms of Physics. I do think you have gotten the wrong impression from the video, or others like it. The universe's topology has nothing to do with time dilation/length contraction. A toroidal universe is actually ( topologically ) flat around the short circumference, because it can be 'transformed' from a flat sheet. The long circumference, however, is not, but you ( and the video, are only considering three dimensions. Adding a fourth dimension doesn't allow for visualizing a 'doughnut' shape. What cosmologist use is a 'flat torus' which is best exemplified by the PacMan game, ( although I did own Atari computers and have played Asteroids ) and where going off one flat edge brings you to the opposite edge. The video does explain that one could ( if the universe was small enough or you could travel fast enough ) notice a difference in travel time, to get back to the original position, when going around the two different circumferences, but that is certainly not time dilation.

Well, let's see. A Einstein's GR predicted light would be bent in the curved space-time of a gravitational field. Sir A Eddington proved him right by observing the Solar eclipse in May 1919. If you live in North America, you can prove it yourself, next Monday; and you'll no longer be able to say, about light bending in a gravitational field, that Obviously, some things can be 🙂 .

Just like a card game at a casino in Atlantic City run by the mob.

Absolutely. But the only one that regularly demands protection from others' opinions, by taking even family members to court, is that joke of a former President, D Trump. But this is still in Astronomy and Cosmology ...

Stems from the new attitude permeating the Western world; that whatever you 'feel' cannot be wrong, and to even mention it can be offensive and you need 'protection' from other's opinions. Meanwhile science teaches us that what is right does not need protection, as it can be proven. But I don't know why this is in Astronomy and Cosmology ...

Could just be the material the shirts are made from. Workout shirts, for example, are made to 'wick' odorous sweat to the outer surface and evaporate.

I'm surprised she found America's actions 'offensive'. The Pacific theater in WW2 saw the death of an estimated 25 Million people, of which about 6 Million were combatants and about 110 Thousand Americans. Yet she finds the death of a couple of hundred thousand, to stop a brutal expansionist war that Japan started, offensive ? Or maybe she found the movie offensive, as it detailed the life experience of a man who helped orchestrate a turning point in history ? I just never realized morality has a PoV.