Well, after that read I can only say I relate to Basel, having been there over Christmas break in 1970. Beautiful city. I wonder if I entered any of the same buildings he did. Our footsteps may have landed on the same spot! Not likely, I can assure you nothing rubbed off. 🙂
The evidence for an expanding universe is overwhelming, as is the interpretation that no matter where you are in the cosmos, it would appear everything is moving away from you. This of course is on a cosmological scale. Where there are local gravitational effects, these are greater - as for example the Milky Way and Andromeda moving toward each other due to gravitational attraction
I don't know if I can pull this off. But Ruby Wax said :
"If my next-door neighbour is having an Affair, I am interested. If my neighbour 3 doors down the Street is having an Affair, I really don't give a Damn."
A question of locality. AFAIK, we Humans don't have to worry about the Expanding Universe. Our local Virgo Cluster is quite secure from such issues.
But am watching the James Webb Space Telescope with interest.
I was recently struck that I and Sir David (Attenborough) share a birthday.
https://en.wikipedia.org/wiki/David_Attenborough
5, 8 and 24 being the most interesting numbers in the Universe.
https://www.scientificamerican.com/article/octonions-web-exclusive/
"If my next-door neighbour is having an Affair, I am interested. If my neighbour 3 doors down the Street is having an Affair, I really don't give a Damn."
A question of locality. AFAIK, we Humans don't have to worry about the Expanding Universe. Our local Virgo Cluster is quite secure from such issues.
But am watching the James Webb Space Telescope with interest.
I was recently struck that I and Sir David (Attenborough) share a birthday.
https://en.wikipedia.org/wiki/David_Attenborough
5, 8 and 24 being the most interesting numbers in the Universe.
https://www.scientificamerican.com/article/octonions-web-exclusive/
Attachments
In the metric expansion of space, it is the space that contains the objects which is itself changing.
It's as if without the objects themselves moving, space is somehow "growing" in between them.
As I think I explained earlier in the thread, the metric is a formula which converts the coordinates of two nearby points into distance.
In the metric expansion of space, it is the formula which is changing - the coordinates stay the same, but the distance between the objects changes.
Apparently, it's all do to with Euclidean/non-Euclidian geometry and how distance is defined in cosmology - away above my pay grade! 😵
I think our knowledge of the expansion of the universe boils down to this:
Q1. Can we observe the expansion of the universe?
A1. Yes
Q2. Can we explain it?
A2. No
Q3. Can we construct a mathematical model that is consistent with the observations?
A3. Yes
What do you think?
Q1. Can we observe the expansion of the universe?
A1. Yes
Q2. Can we explain it?
A2. No
Q3. Can we construct a mathematical model that is consistent with the observations?
A3. Yes
What do you think?
We can assume Time is flowing when one object exchange energy with other if forced . Also how can we say there is no time? What are the measurments we can do to tell yes time is really not flowing .
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All I can do is refer you to Einstein’s view of time. He did not view it as flowing, but as a property of the cosmos called space-time.
You cannot have space between objects without time, just as if time did not pass (hypothetically speaking) space could not exist. The latest thinking in the paper I linked is trying to reconcile the apparent ‘smooth flow’ of space time with the stochastic nature of the quantum world.
I don’t know what kind of measurements you could do to confirm if time flies or not - that’s one for the boffins. I’d have to think about it!
You cannot have space between objects without time, just as if time did not pass (hypothetically speaking) space could not exist. The latest thinking in the paper I linked is trying to reconcile the apparent ‘smooth flow’ of space time with the stochastic nature of the quantum world.
I don’t know what kind of measurements you could do to confirm if time flies or not - that’s one for the boffins. I’d have to think about it!
I have many demands on my Time, but have this problem on the back-burner.
We really don't know what Time is.
My current effort to solve this is a little "chink" I have discovered in Newtonian Mechanics.
https://en.wikipedia.org/wiki/Laplace-Runge-Lenz_vector
Forum favourite John Baez has discussed this one too:
https://johncarlosbaez.wordpress.com/2015/03/17/planets_in_the_4th_dimension/
This is why I try and keep up with Orbital Mechanics. Thing is, Gravity is not quite Inverse Square over long distances.
http://www.scholarpedia.org/article/The_MOND_paradigm_of_modified_dynamics
We really don't know what Time is.
My current effort to solve this is a little "chink" I have discovered in Newtonian Mechanics.
https://en.wikipedia.org/wiki/Laplace-Runge-Lenz_vector
Forum favourite John Baez has discussed this one too:
https://johncarlosbaez.wordpress.com/2015/03/17/planets_in_the_4th_dimension/
This is why I try and keep up with Orbital Mechanics. Thing is, Gravity is not quite Inverse Square over long distances.
http://www.scholarpedia.org/article/The_MOND_paradigm_of_modified_dynamics
Although Einstein's general relativity involved a certain mixing of time and space, time was still different from space.
However, it is now postulated that when the universe was small enough to be governed by both general relativity and quantum theory, there were effectively four dimensions of space and none of time.
If, in the early universe all four dimensions behave like space, where does that place the beginning of time? 🤔
You certainly don't waste any of your time by attempting to answer my questions in the way I attempt to answer yours! 😉
Why do all four dimensions behave like space? I thought the universe started out from a singularity?
Have those dimensions not been published?
come on! you're keeping us at the edge of our cyber seats!
Seriously! it is now postulated?
and you expect me to believe what is presented to the public from the scientific community in general is conceivable?
PFFT 🙂
come on! you're keeping us at the edge of our cyber seats!
Seriously! it is now postulated?
and you expect me to believe what is presented to the public from the scientific community in general is conceivable?PFFT 🙂
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In physics, it is normally assumed that a system has some initial state from which it evolves forward i.e. a singularity.
However, if we take into account the quantum nature of the universe then, like the Feynman sum over all histories for photons, the probability that the universe is in its present state does not depend on an initial state.
In M-theory, space-time has ten space dimensions and one time dimension. Seven of these space dimensions are curled up so small that we don't notice them, leaving us with the illusion that all that exist are the three large space dimensions with which we are familiar.
There will be a quantum possibility for every number of large space dimensions from zero to ten, but like how the act of observing a photon in the double slit experiment determines its position, the probability that we live in a universe of three large space dimensions has already been determined.
Who writes this stuff? 😗
Our familiar four dimensions are: x, y, z and t
The fourth dimension of space I mentioned earlier is an "extra" or "higher" dimension.
Physicists at the LHC look for deviations from the inverse square law of gravitation when they are looking for evidence of extra dimensions.
However, to observe any deviations means dealing with distances which are incredibly small, as these extra dimensions are curled up at a sub-atomic level.
There's published work on the search for extra dimensions if you care to search for it.
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