Anything that appertains to gravity should be allowable here - and what better consequence of gravity is there than a black hole?
What's your take on how we should explain gravity, indra1?
Your Wikipedia link says "rotates ... close to the maximum of 1,150 times per second".
This is significant because there is a theoretical upper limit to the rotational rate of a black hole.
As I said earlier, the faster a black hole spins, the closer its accretion disk can lie to it.
In the limit, as the inner edge of the accretion disc tends towards the event horizon, the linear velocity at the 'equator' of the black hole tends towards the speed of light.
What happens when the limit is reached is a matter of much debate.
Does the event horizon cease to exist, causing the black hole to disappear up its own fundament and become what is known as a naked singularity?
https://en.wikipedia.org/wiki/Naked_singularity
Don't worry Steve. I guarantee I'm a bigger butthead than you are and people still like me. And I'm nowhere near as smart as you.
I now understand what you meant, and I couldn't agree more.
Consequently, I removed the ability to irk by engaging the Ignore function.
Interesting here that 'time must be warped . . .'
To me this screams to the fact that time is everywhere and spreads out from the observer. It calls into question the whole notion of a 'blank canvas' (Newton) or an illusion (Einstein).
We have a theory that the Higgs imparts mass but at a fundamental level, we still have no clear link between mass and 'time warpage'. It could be there is some other mechanism at play. For example, there was a paper published a short while ago proposing that gravity was a very small residual atomic/subatomic force after all other forces were in balance. Then there's QLG
So the explanation still remains open.
Think about 1G standing on the surface of the Earth and 1G being accelerated in deep space the same way Einstein thought about it. In both cases, the accelerative force slows the passage of time down for the body being accelerated. And as pointed out in an earlier post, matter is attracted to regions where time runs more slowly. This is not at odds with the filamentry structure of the universe where small ripples in the fabric of spacetime shorty after the BB expanded outpwards, and matter clustered along these filaments where time ran more slowly. Today, almost all galaxies are in large clusters or located along the interconnecting filaments with giant voids in between. So time is quite lumpy on a cosmic scale - if it were not, the cosmos would be smooth and not the same structure we see today.
Time can be warped because it is one of the dimensions of a four dimensional spacetime which can be warped by the presence of mass and energy.
The warping of the time dimension reveals itself in the way that time passes more slowly at the bottom of a mountain than at the top.
In fact, the Universe is smooth (has a homogeneous and isotropic mass distribution) on a cosmic scale, i.e., over sufficiently large distances.
If we imagine counting the galaxies inside an imaginary box, sufficiently large to contain many galaxies, then that number will not vary much if we choose another equally sized box elsewhere in the Universe.
Galaxies cause the spacetime in their vicinity to be distorted compared to the perfectly smooth average.
We've had this discussion before Galu . All that is being said is that the structure of the universe is the same in all directions, but it remains lumpy at scales of interest where one would want to investigate large scale time warpage because there are clusters, filaments and voids. If it were not so, there would be no clusters, filaments or voids - everything would be very evenly distributed and there would not be large scale time warpage - just warpage around individual galaxies.
I suppose its like a big block of Swiss cheese. From 100 yds away it looks smooth. Stand a bit closer and its anything but.
. All that is being said is that the structure of the universe is the same in all directions, but it remains lumpy at scales of interest where one would want to investigate large scale time warpage because there are clusters, filaments and voids. If it were not so, there would be no clusters, filaments or voids - everything would be very evenly distributed and there would not be large scale time warpage - just warpage around individual galaxies.I suppose its like a big block of Swiss cheese. From 100 yds away it looks smooth. Stand a bit closer and its anything but.
I remember this:Spacetime in the ergoregion is being pulled around by the rotating black hole and so participates in its rotation - an effect known as frame dragging.
Learning all the time!
https://en.wikipedia.org/wiki/Frame-dragging
And especially this:
https://en.wikipedia.org/wiki/Gravity_Probe_B
There was some science show, maybe NOVA, on Gravity Probe B maybe 10 to 15 years ago, and probably a more recent "youtuber" video on it.
Looking at the links, there was the decades-earlier and rather different Gravity Probe A, which was sent into space for just under two hours (not even into an orbit) to "simply" measure the time dilation of gravity:
https://en.wikipedia.org/wiki/Gravity_Probe_A
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Luckily for us, the early Universe was slightly nonuniform, corresponding to the small variations in temperature that are observed in the CMBR.
These irregularities in the early Universe were important because regions of higher density would have slowed down the expansion of those regions and allowed gravity to draw matter together, and eventually cause it to collapse into galaxies.
So the early nonuniformity of the Universe led to the uniformity we see now!
Thre was a brief mention of the probe back in post #764.
The NASA Gravity Probe B mission measured the frame dragging caused by spinning planet Earth!
The combined results from the four gyroscopes, shown above, were in line with the predictions of General Relativity (GR).
Einstein’s GR and Maxwell’s EM equations are the most accurate in physics. Every time our measurement capability advances, the accuracy of the predictions from the equations is further confirmed.
If you put one atomic clock on the ground and move a second one around in the vicinity, the time changes in the second clock wrt the first will precisely obey the GR equations.
I will never understand ‘Einstein was wrong’ claims.
Ok, show me your equations then.
If you put one atomic clock on the ground and move a second one around in the vicinity, the time changes in the second clock wrt the first will precisely obey the GR equations.
I will never understand ‘Einstein was wrong’ claims.
Ok, show me your equations then.
Of course Einstein is and will always be totally wrong, ... in Moronheim Realm, far way beyond the Bifröst.
Entirely rhetorical Galu - just making the general point given your very good post
If there is a theory of something out there, we should start from the point that Einstein was right (see post #1096) and all the other predictions his theory has made that have been verified, Maxwell's EM equations and interpretations are right (after all millions of electrical machines, radio etc all work flawlessly) and QM is also right (semiconductors work as far as I know). Ethan Seagal has I believe two podcasts/articles about this (plus a recent dig at Avi Loeb - I'd love to know how that man manages to hang onto his Harvard professorship given the stuff he's putting out there). Both Carl Sagan and Richard Feynman warned about the slide into 'cargo cult' science 30 years ago.
Might be we can 'interpret' some of this stuff differently and out of that get some new insights, but it would have to be an extraordinary stroke of good luck to build an advanced technological civilisation as we have on these foundational sciences (GR, EM and QM) having got them completely and utterly wrong.