Can we conceptualise the shape of the universe?
Discussion
A friend's daughter is a Physicist and for the past ten years has worked at CERN analysing data and devising experiments.
She is only 32 and has lectured and written papers.
Whenever I see her I attempt to have a conversation on subjects we are discussing here.
At first she humoured me but nowadays she usually gives me a look that says "forget it ".
It might interest you to know that,as I understand it, it's quite difficult for physicists to get a long term permanent job in Physics and that they usually get annual contracts.
All that studying and knowledge and then a struggle for security !
Any of you guys on here that are physicists may like to comment,in case I've got it wrong.
She is only 32 and has lectured and written papers.
Whenever I see her I attempt to have a conversation on subjects we are discussing here.
At first she humoured me but nowadays she usually gives me a look that says "forget it ".
It might interest you to know that,as I understand it, it's quite difficult for physicists to get a long term permanent job in Physics and that they usually get annual contracts.
All that studying and knowledge and then a struggle for security !
Any of you guys on here that are physicists may like to comment,in case I've got it wrong.
AshVX220 said:
I love these kind of subjects, but I quickly find my mind is blown and I'm rapidly out of my depth!
I read a Hawking book a while, and although I read the whole book, I probably only truly grasped about 50% of it.
The subject is way too big for my tiny brain!
I know what you mean,since a boy I've had a fascination with the subject.I read a Hawking book a while, and although I read the whole book, I probably only truly grasped about 50% of it.
The subject is way too big for my tiny brain!
I've also read several books on the subject but the maths defeats me.
In some ways I liken it trying to conceptualise a round Earth when the majority thought the World was flat.
avinalarf said:
I know what you mean,since a boy I've had a fascination with the subject.
I've also read several books on the subject but the maths defeats me.
In some ways I liken it trying to conceptualise a round Earth when the majority thought the World was flat.
Indeed, though with the added benefit of the time (when the Earth was flat) being they at least knew what a sphere looked like! I've also read several books on the subject but the maths defeats me.
In some ways I liken it trying to conceptualise a round Earth when the majority thought the World was flat.
avinalarf said:
Thing that baffles me is,if the Universe is expanding what is it expanding into ?
Is the Universe creating "space" as it expands ?
Even if it is,then that void into which it expands is a something.
So what is that something?
One theory is that eventually the Universe will stop expanding and will collapse into itself,the "Big Crunch".
I rather like this theory as it provides a cycle,Big Bang,Big Crunch...then when the collapse ends there is another Big Bang.
Problem is what created the first Big Bang ?
We can never really understand with any certainty what it is expanding into. This is because whatever it is, it is outside the universe itself. The edge of the universe is one of horizons we can never see past, no matter how long we proceed towards it. The best guess consensus is that it expanding into nothing, expanding is also metaphor. It is more like the expansion of surface area of a balloon rather than the diameter. Yes the expansion is creating space.Is the Universe creating "space" as it expands ?
Even if it is,then that void into which it expands is a something.
So what is that something?
One theory is that eventually the Universe will stop expanding and will collapse into itself,the "Big Crunch".
I rather like this theory as it provides a cycle,Big Bang,Big Crunch...then when the collapse ends there is another Big Bang.
Problem is what created the first Big Bang ?
The Big crunch is the Closed universe mentioned above.
4x4Tyke said:
We can never really understand with any certainty what it is expanding into. This is because whatever it is, it is outside the universe itself. The edge of the universe is one of horizons we can never see past, no matter how long we proceed towards it. The best guess consensus is that it expanding into nothing, expanding is also metaphor. It is more like the expansion of surface area of a balloon rather than the diameter. Yes the expansion is creating space.
The Big crunch is the Closed universe mentioned above.
I've read about the balloon concept,wasn't that an Einstein premise ?The Big crunch is the Closed universe mentioned above.
I don't understand what you refer to as the expansion of the surface area rather than the diameter,can you please explain.
So as we think that time and space are relative are we saying that as our Universe expands it is creating Space/Time.
Therefore there is nothing beyond the Membranes of the Universe as it doesn't exist in Time or Space ?
Is this connected to a fourth Dimension?
Fugazi said:
I thought that (closed universe) had been disproved, something to do with the critical density of the universe. If the density of the universe exceeds the critical density, then gravity will eventually slow down the expansion and the universe would collapse back into itself. I don't remember the details, but last thing I read on the subject, the universe's density was below the critical value and was found to be that expected for a 'flat' universe.
I didn't think the open closed question is actually settled, it is known the curvature is very slight, less than our current available instruments can discriminate. This is why a small fortune is being spent on the James Web telescope which is the most expensive satellite ever built. AIUI it will only settle the question if the density is more than the telescopes margin or error.This is all related to the questions of the missing mass in the universe, the apparent imbalance between matter and anti-matter and the search for WIMPs.
Schroedinger get us into a whole new universe of weird. Does the universe exist because there is an observer within the universe. The ultimate chicken and egg question. Is the universe expanding because the passage of time increases the observable universe. Those expanding cosmological horizons mentioned earlier.
Weird stuff, no other word for it.
Fugazi said:
Also topology is a fascinating subject, things like Mobius strips that can exist in 3D space, but have only a single edge and a single surface. Klein Bottles are similar to Mobius Strips in that they're a 4 dimensional object represented in 3 dimensional space, and again have only one surface, no edges and cannot hold a volume. Things get even weirder in higher dimensions, Strange spheres in higher dimensions.
These are really mind blowing as well, there are similar videos many other shapes and transformation.https://www.youtube.com/watch?v=q5Qh2XpoCsY
https://www.youtube.com/watch?v=XFW769hqa1U
They really do expose the difficultly of the initial problem, how can we visualise this stuff.
avinalarf said:
I've read about the balloon concept,wasn't that an Einstein premise ?
I don't understand what you refer to as the expansion of the surface area rather than the diameter,can you please explain.
So as we think that time and space are relative are we saying that as our Universe expands it is creating Space/Time.
Therefore there is nothing beyond the Membranes of the Universe as it doesn't exist in Time or Space ?
Is this connected to a fourth Dimension?
The diameter of balloon is expanding in some space, the surface area isn't. The surface is expanding within its self. I was trying express that cosmological space is not expanding into some kind of other-space. Some use the idea of stretching, but again that word doesn't really properly express what is happening either. We are limited by the fact we use common words like space, expands, open, closed which are very general in ordinary meaning, in these a very metaphorical way for this discussion. The vocabulary just doesn't exist in English, hence the need for the maths.I don't understand what you refer to as the expansion of the surface area rather than the diameter,can you please explain.
So as we think that time and space are relative are we saying that as our Universe expands it is creating Space/Time.
Therefore there is nothing beyond the Membranes of the Universe as it doesn't exist in Time or Space ?
Is this connected to a fourth Dimension?
AIUI the space in Space-Time is being created by an expanding universe, but not sure about Time.
The rest is beyond my limits of understanding and ability to explain what I think I understand, sorry.
Edited by 4x4Tyke on Thursday 9th November 19:14
The difficulty in visualising it come from our attempt to visualise it I guess - it seems easy to think 'if I stand back far enough, what would it look like - it must look like something right?' but we're tuned to 3 dimensions and see and understand things on that level, whereas the universe, time, light, space and energy act beyond our normal apprehension on the large scale, much like particles act beyond the intuitive at quantum scale. If you look at descriptions of a hyper-sphere and get your head around that and see why we could set off in a straight line and end up where we started as space is itself bent, you're getting some way there I think. In this context, 'shape' has no real meaning. [This has been my interpretation at least!!].
The expanding/contracting universe question is interesting, and normally it is 'expanding' (well, our notion of 'space' is expanding) although bear in mind we have the common view that 80% or more of the universe is undetected 'dark matter', a particularly unsatisfactory explanation for what appears to be happening around us [not only the expansion of the universe, but spiral galaxy orbiting speeds / gravity clustering]. There is something fairly substantial we are perhaps not getting, it could be neutrinos have mass after all, or gravity [space/time] behaves differently than we think [information propagation, granularity etc] or a few other explanations/theories, but it does remain a great unknown.
It's all fascinating stuff - what's fascinating is that to understand the biggest things, you have to understand the tiniest things; it's so interconnected...and way beyond me!
The expanding/contracting universe question is interesting, and normally it is 'expanding' (well, our notion of 'space' is expanding) although bear in mind we have the common view that 80% or more of the universe is undetected 'dark matter', a particularly unsatisfactory explanation for what appears to be happening around us [not only the expansion of the universe, but spiral galaxy orbiting speeds / gravity clustering]. There is something fairly substantial we are perhaps not getting, it could be neutrinos have mass after all, or gravity [space/time] behaves differently than we think [information propagation, granularity etc] or a few other explanations/theories, but it does remain a great unknown.
It's all fascinating stuff - what's fascinating is that to understand the biggest things, you have to understand the tiniest things; it's so interconnected...and way beyond me!
We can only see the observable universe, which is a sphere extending out many billions of light years with Earth at the 'centre'.
So the observable universe is spherical, the entire universe shape however is an unknown.
The term "shape" also may need a bit of definition, because 4D space time is curved by energy/mass , but overall as light travels in a straight line the universe is said to be 'flat'.
So the observable universe is spherical, the entire universe shape however is an unknown.
The term "shape" also may need a bit of definition, because 4D space time is curved by energy/mass , but overall as light travels in a straight line the universe is said to be 'flat'.
Quote/Tyke
Schroedinger get us into a whole new universe of weird. Does the universe exist because there is an observer within the universe. The ultimate chicken and egg question. Is the universe expanding because the passage of time increases the observable universe. Those expanding cosmological horizons mentioned earlier."
Quantum Physics is fascinating.
Simply put it says that the outcome of an an experiment is altered when/if it is observed.
As we know,everything is composed of atoms and not "solid" ,so everything we "see" is in a state of flux.
So nothing is "real" unless it is observed.
Imagine you are in a room without any light,as you cannot see anything you could say that there is nothing else but you and your sense of being.
Turn on a light and the whole scenario becomes observable,however it is confined within those four walls.
It is only when we exit that room that we can see that which is outside.
Does that make any sense ?
In Genesis it says "And God created the light,and it was good."
Don't worry I'm not getting all religious on you but it is food for thought.
As I see it as the Universe expands it creates time.
Think of the Big Bang.
Before the Big Bang there was "nothing".... No Space or Time.
Immediately after the Big Bang the Universe started to expand and Time began.
Therefore Space and Time are relative.
Schroedinger get us into a whole new universe of weird. Does the universe exist because there is an observer within the universe. The ultimate chicken and egg question. Is the universe expanding because the passage of time increases the observable universe. Those expanding cosmological horizons mentioned earlier."
Quantum Physics is fascinating.
Simply put it says that the outcome of an an experiment is altered when/if it is observed.
As we know,everything is composed of atoms and not "solid" ,so everything we "see" is in a state of flux.
So nothing is "real" unless it is observed.
Imagine you are in a room without any light,as you cannot see anything you could say that there is nothing else but you and your sense of being.
Turn on a light and the whole scenario becomes observable,however it is confined within those four walls.
It is only when we exit that room that we can see that which is outside.
Does that make any sense ?
In Genesis it says "And God created the light,and it was good."
Don't worry I'm not getting all religious on you but it is food for thought.
As I see it as the Universe expands it creates time.
Think of the Big Bang.
Before the Big Bang there was "nothing".... No Space or Time.
Immediately after the Big Bang the Universe started to expand and Time began.
Therefore Space and Time are relative.
avinalarf said:
Quote/Tyke
Time began.
Therefore Space and Time are relative.
Some argue spacetime has no time dimensionTime began.
Therefore Space and Time are relative.
“One can travel in space only, and time is a numerical order of his motion.”
https://phys.org/news/2011-04-scientists-spacetime...
So before the big bang time doesn't need to exist, no motion, no time. What caused the motion could be by the appearance of virtual particles, that can come of of nothing.
https://www.scientificamerican.com/article/somethi...
"Virtual particles" can become real photons--under the right conditions
The Spruce goose said:
Some argue spacetime has no time dimension
“One can travel in space only, and time is a numerical order of his motion.”
https://phys.org/news/2011-04-scientists-spacetime...
So before the big bang time doesn't need to exist, no motion, no time. What caused the motion could be by the appearance of virtual particles, that can come of of nothing.
https://www.scientificamerican.com/article/somethi...
"Virtual particles" can become real photons--under the right conditions
I have read both the above articles and they appear to back up my theory.“One can travel in space only, and time is a numerical order of his motion.”
https://phys.org/news/2011-04-scientists-spacetime...
So before the big bang time doesn't need to exist, no motion, no time. What caused the motion could be by the appearance of virtual particles, that can come of of nothing.
https://www.scientificamerican.com/article/somethi...
"Virtual particles" can become real photons--under the right conditions
That time,on its own does not exist,it is purely a measurement relative to movement.
On Earth our concept/measurement of Time is relative to the time it takes for the Earth to rotate around the sun.
If we were to live on another planet this measurement would be meaningless.
As the Universe is composed of particles that are always in a state of motion this rationalises the concept of Time.
Maybe this could also explain the fact that in QP the outcome of an experiment is altered when it is being observed.
The fact that our notion of Time affects the reality.
Does this make any sense ?
In the same way we need to be careful about the way we us the word space, we need to be equally careful about how we use the word time. Time as we all understand it in normal life is governed by out own perceptions, our biological clock, the earth's rotation and calendars.
The word time in physics is another metaphor, an approximation for the maths and there are several definitions of time that have emerge through history and in the different theories of cosmology. In Einstein's spacetime, time is relative and includes time dilation under gravity and velocity. Time be speed up and slowed down in special relativity, while in our perception it is (largely) fixed.
Minkowski, who was Einstein's mentor had previously devised something now known as Minkowski spacetime. This is an earlier model and simplification. Minkowski which uses time as an interval between points in a similar way to a vector in Carteasian co-ordinates. So we have up/down, left/right, forward/back as opposed to fixed coordinates X,Y, Z.
So while can move freely in space, we cannot do the same in time, we can only move forward. Time is in many ways the same as space in how it can be measure (X,Y,Z)+T it is also different. We can measure differences in time, for example clocks on earth run slower than the clocks on the GPS satellites. However we cannot manipulate out position in time, like we can with space.
The word time in physics is another metaphor, an approximation for the maths and there are several definitions of time that have emerge through history and in the different theories of cosmology. In Einstein's spacetime, time is relative and includes time dilation under gravity and velocity. Time be speed up and slowed down in special relativity, while in our perception it is (largely) fixed.
Minkowski, who was Einstein's mentor had previously devised something now known as Minkowski spacetime. This is an earlier model and simplification. Minkowski which uses time as an interval between points in a similar way to a vector in Carteasian co-ordinates. So we have up/down, left/right, forward/back as opposed to fixed coordinates X,Y, Z.
So while can move freely in space, we cannot do the same in time, we can only move forward. Time is in many ways the same as space in how it can be measure (X,Y,Z)+T it is also different. We can measure differences in time, for example clocks on earth run slower than the clocks on the GPS satellites. However we cannot manipulate out position in time, like we can with space.
4x4Tyke said:
I'm an uber-geek, scientist by education, IT by profession with lifelong interest in Physics & Biology, less so Chemistry.
Excellent....I was beginning to wonder if you may have been copy and pasting info.Nothing wrong with that but it's comforting to know that you actually understand what you're posting.
With me it's just a layman's fascination for the subject.
I get frustrated that maths and techy stuff are not my strengths.
I try and use language to conceptualise my ideas,not easy when it comes to QP, but defeated by my inability to grasp the mathematical proofs.
avinalarf said:
Excellent....I was beginning to wonder if you may have been copy and pasting info.
Nothing wrong with that but it's comforting to know that you actually understand what you're posting.
With me it's just a layman's fascination for the subject.
I get frustrated that maths and techy stuff are not my strengths.
I try and use language to conceptualise my ideas,not easy when it comes to QP, but defeated by my inability to grasp the mathematical proofs.
As an aside, and if you haven't already, I'd recommend Carlo Rovelli's book 'Reality is Not What it Seems' for some interesting and insightful thinking that's [fairly] easily digestible for the layperson without a reliance on showing the proof through the maths; I'm in the same boat as yourself and enjoyed it immensely. Nothing wrong with that but it's comforting to know that you actually understand what you're posting.
With me it's just a layman's fascination for the subject.
I get frustrated that maths and techy stuff are not my strengths.
I try and use language to conceptualise my ideas,not easy when it comes to QP, but defeated by my inability to grasp the mathematical proofs.
andy_s said:
As an aside, and if you haven't already, I'd recommend Carlo Rovelli's book 'Reality is Not What it Seems' for some interesting and insightful thinking that's [fairly] easily digestible for the layperson without a reliance on showing the proof through the maths; I'm in the same boat as yourself and enjoyed it immensely.
Thank you,I'll get a copy.Gassing Station | Science! | Top of Page | What's New | My Stuff