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We are forgetting about "star trek" inspired inertial dampers. 😉

When Betelgeuse goes supernova, it will simply spew its enriched guts of elements into space. It will in all likelyhood leave a BH in its place, and in the course of time, gravity may condense the enriched guts from the original star, to ignite another generation star. This is nothing like the BB, which was the evolution of space and time. There was no matter at the BB. This is an important point. The only center one can logically speak of with regarding an expanding universe, is the center of one's observable universe as String Junky says, emanating out in all directions from a particular point. This follows from the fact that the BB occurred in all of spacetime, as all of spacetime was confined to within the size of an atomic nucleus. Best analogy is claiming any center on the surface of an inflating balloon...the 2 dimensional surface, representing 4 dimensional spacetime.

Precisely. Even IF there was any doubt re human contribution to climate change, with what is potentially at stake [a habitable planet] it is far better to err on the side of caution. As a member of the public, I hope I do my little bit to help things...over the last 5 years I'm averaging around 10,000kms yearly in driving [also means insurance discount] recycling of plastics etc...air conditioner on only in extreme conditions...solar panels...LED household lights...Laundry/Washing clothes in cold water...4 minute showers, are some of the contributions my family are making.

The facts are that over smaller scales, the strong nuclear, weak nuclear, and gravity, overcome the expansion rate. Is the expansion uniform? Best observational evidence so far tells us yes, it is, and that the universe is isotropic and homogenous in all directions. However there maybe reason to believe this may not be the case..... https://www.nasa.gov/mission_pages/chandra/news/universe-s-expansion-may-not-be-the-same-in-all-directions.html extracts: "Based on our cluster observations we may have found differences in how fast the universe is expanding depending on which way we looked,” said co-author Gerrit Schellenberger of the Center for Astrophysics | Harvard & Smithsonian (CfA) in Cambridge, Massachusetts. “This would contradict one of the most basic underlying assumptions we use in cosmology today.” The authors of this new study came up with two possible explanations for their results that involve cosmology. One of these explanations is that large groups of galaxy clusters might be moving together, but not because of cosmic expansion. For example, it is possible some nearby clusters are being pulled in the same direction by the gravity of groups of other galaxy clusters. If the motion is rapid enough it could lead to errors in estimating the luminosities of the clusters. These sorts of correlated motions would give the appearance of different expansion rates in different directions. Astronomers have seen similar effects with relatively nearby galaxies, at distances typically less than 850 million light years, where mutual gravitational attraction is known to control the motion of objects. However, scientists expected the expansion of the universe to dominate the motion of clusters across larger distances, up to the 5 billion light years probed in this new study. A second possible explanation is that the universe is not actually the same in all directions. One intriguing reason could be that dark energy – the mysterious force that seems to be driving acceleration of the expansion of the universe – is itself not uniform. In other words, the X-rays may reveal that dark energy is stronger in some parts of the universe than others, causing different expansion rates. “This would be like if the yeast in the bread isn’t evenly mixed, causing it to expand faster in some places than in others,” said co-author Thomas Reiprich, also of the University of Bonn. "It would be remarkable if dark energy were found to have different strengths in different parts of the universe. However, much more evidence would be needed to rule out other explanations and make a convincing case." Either of these two cosmological explanations would have significant consequences. Many studies in cosmology, including X-ray studies of galaxy clusters, assume that the universe is isotropic and that correlated motions are negligible compared to the cosmic expansion at the distances probed here. ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: At present I would say the principle of isotropy and homogeneity still appear to hold overall...but obviously the science of cosmology is an ever changing discipline, based on new and further observational and experimental data.

Yes, I sorta smelt that too. smelt or smelled...whatever the case maybe.

As we speak, Australia has now locked out New Zealand [the two countries previously had a travel bubble] due to a small outbreak of the contagious variant of covid 19....[2 cases] Also Melbourne as undergone a 5 day lockdown after a similar outbreak of this new more contagious variety, from hotel quarantine, via a "banned" breathing nebulizer. Obviously both outbreaks are minimal, and the prompt action taken, should see it contained and eliminated. Lockdown in Australia and New Zealand are enforced pretty strictly, with some exemptions...[1] 2 hr excersise period a day [1] visit to medical facility if urgent. [3] Urgent shopping. [4] Work that cannot be done at home. No travel further then 5km from home, no visitors, school shutdowns, masks compulsory on public transport. Yet in spite of the success of Australia and New Zealand in containing this virus, politics still rears its ugly head. A woman was thrown off a bus in Sydney because she claimed being forced to wear a mask was a violation of her liberties...there have been attempted marches in both Sydney and Melbourne by extremists claiming their so called rights are being violated, some of those protesters infected with another imported American variant of this virus, sporting Trump caps and insignias.

At my current age of 76 years, I'm still enjoying life and have no real health problems. In actual fact I plan on living forever: So far, I'm doing OK. 😉

By definition that is wrong. If scientists perceive a paradox in nature, you can bet your short n curlies that it is because they themselves have made a mistake as to the nature of nature, which is nature. 😉

Likewise. They were not wrong with the stunning, thought provoking photo of the Polar bear on thin ice.

That you are wrong.

By twist, I meant the Lense Thirring Effect. Poor choice of word.

My observation as an outsider in this impeachment, is that if justice is not done, and Trump is found innocent, then this will buoy him, and his supporters, to further unconstitutional and disgraceful antics that may take place, culminating in more of the usual lies etc, and then an attempt again in 4 years. Let's hope justice is done.

Einstein and General Relativity showing how mass/energy density warp, curve, twist spacetime. Person? Carl Sagan who personally sparked my interest in cosmology but sadly too late to really do much about it except learn. As he said Cosmology/astronomy is a humbling and character building experience...from that unforgetable description entitled "Pale Blue Dot"

We are as yet unaware whether the universe is finite or infinite, or whether multiverses exist or not. We are only able to speculate.

Certainly. Three eloquent posts that typify the epitome of science. Just for the information of wildie9, the collision of M31 and the Milky Way, or any other galaxy, is actually more of a merger then collision. The vast distances between stellar objects would see actual collisions fairly rare.

Personally I have nothing against religious people, or religion for that matter. In a vast majority of cases in this day and age, I believe people use it and practise it, more as a comfort entity then anything else, and as a wall against the scientifically based conclusion that death is it...it is final and the end. That worries many people imo, and religion gives them that inner warm fuzzy feeling that upon their death, they will be magically transported to heaven or its equivalent. There are many good decent religious people in this world that mean well, and truly practise the basis of their religion. My Mrs is one of them. She was born in Fiji, now a naturalized Aussie, and like almost all Fijians, have a strong religious connection, based on Christianity or Hindi for Indian Fijians. She also puts up with me. But basically, we tolerate our differences and have been together for 42 years now, and both our first marriages. My only beef against religious people are the one's that come to science forums such as this and others, preaching their fire and brimstone, and attempting to belittle science. I have seen the video in the opening post, and while I like both those esteemed scientists, Carl Sagan imo had a far more subtle approach to people of a religious leaning. But that's a personal taste. I don't particularly see myself as an Atheist, more a student of reasonability and scientific application, that simply sees any God as a mythical entity constructed to bring comfort to an individual, and as a companion to their ignorance of science and the scientific explanation.

Yeah, good point actually. Have you seen this model of a BH? https://jila.colorado.edu/~ajsh/insidebh/waterfall.html and the paper.....https://arxiv.org/pdf/gr-qc/0411060.pdf

Another good question. I think you answered it yourself...space is not a physical thing...it doesn't flow, per se...it just expands, unless that expansion is overcome/decoupled by mass/energy density. Space not being a physical thing, does not though [imo] make it any the less real. But hey! I'm here to learn also! Anyone with a better explanation?

Can I modify the above from my last post.....should read, "it is only space that is seen to be expanding, at the most observable distances of our universe, and the distant galaxies taken along for the ride" In effect, all of space is expanding, but regions where the matter/energy density is high, [due to the strong, weak nuclear forces, EMF and gravity] is "decoupled" from the expansion rate. eg; Us, Earth, solar system, galaxy, galactic group, and galactic cluster.

As others have said, a great question. In effect it is only space expanding, at the most observable distances of our universe...our solar system is gravitationally bound...our galaxy is gravitationally bound, our local group is gravitationally bound [including Andromeda] and our cluster of galaxies is gravitationally bound. Only galaxies beyond our cluster will appear to be moving away due to the expansion of space. https://en.wikipedia.org/wiki/Galaxy_cluster In a few billion years. 😉 And by that time, our Sun will have reached the giant red phase, and become a White Dwarf, the Moon will be double its distance from Earth then it is now, and a day on Earth [if we are not swallowed up by the Sun] will be equal to a lunar month.

https://www.csiro.au/en/News/News-releases/2020/Cosmic-bursts-unveil-missing-matter Cosmic bursts unveil Universe’s missing matter: 20th May 2020 The researchers have now found all of the missing 'normal' matter in the vast space between stars and galaxies, as detailed today in the journal Nature . extract: "Intergalactic space is very sparse," he said. "The missing matter was equivalent to only one or two atoms in a room the size of an average office." "So it was very hard to detect this matter using traditional techniques and telescopes."

For such speculation to be real, we would need to discard Einstein's SR, which of course is a special case of GR. Any matter would need to have mass and take up space...light has zero rest mass. As matter approaches light speed, it gets heavier from our perspective. At 'c' we would need an infinite amount of energy. Hypothetically speaking the Tachyon is a particle created at FTL and maintains that speed. Problem of course is that it conflicts with relativity and our laws of physics. Our successful models of gravity, Newtonian and GR work in near all cases. It would be illogical imo to drop them simply to explain, or attempt to explain DM and/or DE, when both can be encompassed by GR anyway. None of that in anyway curtails physicists and scientists from speculating, and hypothesising certain scenarios. There are scientific papers everyday that do that, but there they remain, gathering dust, until evidence is found supporting a particular scenario, or invalidating GR. Just as an aside, and as an amateur, I dont see SR/GR as invalidating Newtonian mechanics [afterall we use it everyday, including most all space endeavours] rather it gives us a more accurate picture of gravity beyond that given by Newtonian. Afterall we could use GR calculations in all our Earthly and space endeavours and get the same answers, but the complications in those calculations and methodology would take far more time and effort then the simplistic quick Newtonian method.

You need to use the quote function properly Olorin...the above is not part of any of my posts and as you posted, quoted by me. Again, I do not see any connection between sprites and plate tectonics.

The thing is that we are here. And obviously ignoring the creationists myths, we, the universe evolved from somewhere. The basic fundamental quantum foam, may be as close to nothing as is possible, and from which when the appropriate fluctuation arose, evolved the universe/space/time that we are familiar with.

All matter/energy warps, curves, twists spacetime, and we see that deformation of flat spacetime as gravity. Dark Matter though differs from normal baryonic matter, in that it does not interact with light, neither absorbing or reflecting or emitting any part of the electromagnetic spectrum. Hence we don't see it, and can only infer its existence by its gravitational effects.