;-)
May be, it's not a compass, or even a ruler or a clock or a calculator, the most important instrument of a "hard" physicist, a scientist, researcher. It is a mirror;-)
If Einstein had received a mirror as a present, we would not have the vexing RT now;-)
There is a reason, why the "expanding space-time" seems to be especially interested in the thighs of your girls: they regularly sit at their coffee meetings and, laughing tears, slap their thighs at the stories about their boys:
Susi: "Mine has build Tensors out of toy blocks..."-)
Franci: "Mine has draw dots on a paper, fold it and say he warps dots..."-))
Moni: "Mine has stand in front of the mirror and say, his mirror picture contains a lot of potential..."-)))
Your girls are probably further: With a look in the mirror one sees: "vacuum", "space" - and they would not attribute potentials or curvature or expandability to the mirror image -; it provides, hopefully, access to the understanding of concepts: mental constructs, ideas, imaginations: "space"-"time", "vacuum", "energy"...-)
... but don't start now to bend mirrors and to claim to bend space in the mirror or to elicit vacuum potential;-)
May be, it's not a compass, or even a ruler or a clock or a calculator, the most important instrument of a "hard" physicist, a scientist, researcher. It is a mirror;-)
If Einstein had received a mirror as a present, we would not have the vexing RT now;-)
There is a reason, why the "expanding space-time" seems to be especially interested in the thighs of your girls: they regularly sit at their coffee meetings and, laughing tears, slap their thighs at the stories about their boys:
Susi: "Mine has build Tensors out of toy blocks..."-)
Franci: "Mine has draw dots on a paper, fold it and say he warps dots..."-))
Moni: "Mine has stand in front of the mirror and say, his mirror picture contains a lot of potential..."-)))
Your girls are probably further: With a look in the mirror one sees: "vacuum", "space" - and they would not attribute potentials or curvature or expandability to the mirror image -; it provides, hopefully, access to the understanding of concepts: mental constructs, ideas, imaginations: "space"-"time", "vacuum", "energy"...-)
... but don't start now to bend mirrors and to claim to bend space in the mirror or to elicit vacuum potential;-)
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On reflection, are we talking a plane, convex or concave mirror?
We wouldn't want to have a distorted view of physics, would we? 😉
We wouldn't want to have a distorted view of physics, would we? 😉
You supplied an interesting link which, unfortunately, I could only read once: https://www.cantorsparadise.com/the-genesis-of-kerr-solution-dd778e6be598
The rotating Kerr solution is the most realistic black hole scenario, and involves a ring singularity (see first attachment).
A Schwarzschild non-rotating black hole which involves a point singularity (r=0) probably doesn’t exist. (see second attachment).
The link mentions frame-dragging which is when spacetime itself gets dragged round by a rotating object.
The effect was first predicted in 1918 as a natural consequence of General Relativity (GR).
It was confirmed that Earth generates frame dragging in line with GR's predictions when the NASA Gravity Probe B (GP-B) mission managed to measure the effect around our planet. (see third attachment).
Evidence of frame-dragging by a black hole is apparently a wobbling of the accretion disc, similar to the wobbling of a spinning top as it slows down.
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That's OK. I was referring to the content of The Wise One's post which was thigh slappingly funny!
Did you even understand it? Cats and mirrors debunk science? I can't keep up with the quackery. I still wonder if he's serious, or seriously stupid.
"The universe is all of space and time[a] and their contents,[10] including planets, stars, galaxies, and all other forms of matter and energy." Wikipedia.
Universe is all. All, Totality. Does not expand.
It is claimed that "spacetime" expands. Mostly "space-time" is equated with universum, all, totality. Without permission and unscientifically;-)
But it would be logical, if "we" were "interwoven" with "space-time", expanded with;-) Otherwise we would have to introduce another quantity into "hard" physics: second "spacetime"-)
... so that the nonsense still seem logical;-)
Do you are sure, really;-?
Or wouldn't you rather look in the mirror;-? After all;-)
The SpaceX Falcon 9 rocket has lifted off and the mission to map the Universe across space and time has begun.
Mapping the shape, position and movement of galaxies will reveal how matter is distributed across the Universe and help scientists improve the understanding of the role gravity plays in its evolution.
Euclid will be placed in orbit around Sun-Earth Lagrange point 2 located 1.5 million km from Earth in the direction opposite from the Sun.
There's a big British input to this mission, not least of which is the fact that one of the two cameras on board was designed by University College London (UCL).
Excellent. Some Physics again! I was thinking this was a just a collection of random tweets...
I have downloaded the Euclid Press Pack from ESA. It is another of those cold telescopes like JWST at the Lagrange L2 point. But a highly detailed visible spectrum widefield view designed in the UK.
https://www.esa.int/Science_Exploration/Space_Science/Euclid
It has the equivalent of greater than 36 X 4K sensors.
It plans on totally mapping a third of the sky over 6 years. Above and below the Galactic Plane. It also has a NASA Infra-Red Sensor.
Some fairly self-explanatory illustrations:
I have downloaded the Euclid Press Pack from ESA. It is another of those cold telescopes like JWST at the Lagrange L2 point. But a highly detailed visible spectrum widefield view designed in the UK.
https://www.esa.int/Science_Exploration/Space_Science/Euclid
It has the equivalent of greater than 36 X 4K sensors.
It plans on totally mapping a third of the sky over 6 years. Above and below the Galactic Plane. It also has a NASA Infra-Red Sensor.
Some fairly self-explanatory illustrations: