so I Googled what is the universe expanding into.
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MolaKule
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Originally Posted By: fdcg27
You bring this up again and you actually teach it?
Yes sir I do.
You bring this up again and you actually teach it?
Yes sir I do.
MolaKule
Staff member
Originally Posted By: fdcg27
...Okay, so the universe is flat.
Then how do you explain the observed effect of gravitational lensing?
It's pretty well accepted that concentrations of mass have an effect upon the time/space continuum...
I posted this but it somehow disappeared:
We have to be careful about gravitational lensing and its interpretation.
Rather recent observations have found multiple images of the same exact Quasar.
Each Quasar has a unique spectral image.
It was discovered that single Quasars behind certain Galaxies showed up as multiple images due to gravitational lensing.
The reason these were detected is these multiple Quasars showed the same exact spectral lines.
...Okay, so the universe is flat.
Then how do you explain the observed effect of gravitational lensing?
It's pretty well accepted that concentrations of mass have an effect upon the time/space continuum...
I posted this but it somehow disappeared:
We have to be careful about gravitational lensing and its interpretation.
Rather recent observations have found multiple images of the same exact Quasar.
Each Quasar has a unique spectral image.
It was discovered that single Quasars behind certain Galaxies showed up as multiple images due to gravitational lensing.
The reason these were detected is these multiple Quasars showed the same exact spectral lines.
Originally Posted By: fdcg27
Okay, so the universe is flat.
Then how do you explain the observed effect of gravitational lensing?
It's pretty well accepted that concentrations of mass have an effect upon the time/space continuum.
At the theoretical level, we have theories of things like wormholes that would exploit the lack of flatness.
Gravitational lensing (and spacetime distortions in general due to massive objects) is a local phenomenon, not indicative of the structure of space itself. Massive objects cause distortions yes but in the grand scheme of things they are small and localized. The very fact that they can be detected is because of the flatness of space.
The structure of space itself is extremely, almost unbelievably flat and that is what WMAP showed. If it were not flat, distant objects could not be observed. Look at that article I linked, the fundamental flatness of space itself is related on the energy of the vacuum not on the presence of mass. Sure, localized distortions occur but that's not the same thing.
Okay, so the universe is flat.
Then how do you explain the observed effect of gravitational lensing?
It's pretty well accepted that concentrations of mass have an effect upon the time/space continuum.
At the theoretical level, we have theories of things like wormholes that would exploit the lack of flatness.
Gravitational lensing (and spacetime distortions in general due to massive objects) is a local phenomenon, not indicative of the structure of space itself. Massive objects cause distortions yes but in the grand scheme of things they are small and localized. The very fact that they can be detected is because of the flatness of space.
The structure of space itself is extremely, almost unbelievably flat and that is what WMAP showed. If it were not flat, distant objects could not be observed. Look at that article I linked, the fundamental flatness of space itself is related on the energy of the vacuum not on the presence of mass. Sure, localized distortions occur but that's not the same thing.
MolaKule
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Originally Posted By: kschachn
Originally Posted By: NGRhodes
Quote:
The standard Big-Bang cosmological model is based on the idea that the Universe is homogeneous and isotropic. One sort of homogeneous spacetime has the geometry of a 3-sphere (like a regular sphere, but with one more dimension). In these cosmological models, if you travel far enough you get back to where you started.
Which by all accounts is astonishingly true. This is an old article but a good one, and illustrates the point very well:
http://pages.erau.edu/~reynodb2/blog/Abbott_CosmologicalConstant_SciAm.pdf
Flat as a pancake. A very, very flat pancake.
That is a very good paper on the Comological Constant and it is a problem to be dealt with.
The Problem of the Cosmological Constant as a contradiction between the Theoretical and the Observational aspects:
The theoretical problem is this: Theoretical estimates of the cosmological constant says it should be very large, but according to observation, the cosmological constant is very, very small, but above zero. The scale of this problem is serious and embarrassing such that many cosmologists rarely mention it or want to mention it.
P. de Bernadis, et. al., also supports the Flat Universe in their paper, A Flat Universe from High-resolution Maps of Cosmic Background Radiation, Nature 404:955-999, (2000).
Lawrence Krauss says, “the cosmological constant would involve the most extreme fine-tuning problem known in physics, and for this reason, many particle physicists would prefer any mechanism that would drive the cosmological constant to be exactly zero today.”
He also says, “It is getting increasing difficult to find accord with a flat universe without a cosmological constant. The question then becomes: Which fundamental fine-tuning problem is one more willing to worry about, the flatness problem or the cosmological constant problem? The latter involves a fine-tuning of perhaps only 60 orders of magnitude." See: Lawrence Krauss, The End of the Age Problem, and the Case for a Cosmological Constant Revisited, The Astrophysical Journal, 501:461-466 (1998).
The universe is looking flatter and the energy density due to a cosmological constant is now statistically well above zero. See: Adam Burrows, Supernova Explosions in the Universe, Nature:403:727-73 (2000).
These authors also tackle the problem but attribute it to an “unknown agent."
https://arxiv.org/pdf/hep-th/0208013.pdf
Originally Posted By: NGRhodes
Quote:
The standard Big-Bang cosmological model is based on the idea that the Universe is homogeneous and isotropic. One sort of homogeneous spacetime has the geometry of a 3-sphere (like a regular sphere, but with one more dimension). In these cosmological models, if you travel far enough you get back to where you started.
Which by all accounts is astonishingly true. This is an old article but a good one, and illustrates the point very well:
http://pages.erau.edu/~reynodb2/blog/Abbott_CosmologicalConstant_SciAm.pdf
Flat as a pancake. A very, very flat pancake.
That is a very good paper on the Comological Constant and it is a problem to be dealt with.
The Problem of the Cosmological Constant as a contradiction between the Theoretical and the Observational aspects:
The theoretical problem is this: Theoretical estimates of the cosmological constant says it should be very large, but according to observation, the cosmological constant is very, very small, but above zero. The scale of this problem is serious and embarrassing such that many cosmologists rarely mention it or want to mention it.
P. de Bernadis, et. al., also supports the Flat Universe in their paper, A Flat Universe from High-resolution Maps of Cosmic Background Radiation, Nature 404:955-999, (2000).
Lawrence Krauss says, “the cosmological constant would involve the most extreme fine-tuning problem known in physics, and for this reason, many particle physicists would prefer any mechanism that would drive the cosmological constant to be exactly zero today.”
He also says, “It is getting increasing difficult to find accord with a flat universe without a cosmological constant. The question then becomes: Which fundamental fine-tuning problem is one more willing to worry about, the flatness problem or the cosmological constant problem? The latter involves a fine-tuning of perhaps only 60 orders of magnitude." See: Lawrence Krauss, The End of the Age Problem, and the Case for a Cosmological Constant Revisited, The Astrophysical Journal, 501:461-466 (1998).
The universe is looking flatter and the energy density due to a cosmological constant is now statistically well above zero. See: Adam Burrows, Supernova Explosions in the Universe, Nature:403:727-73 (2000).
These authors also tackle the problem but attribute it to an “unknown agent."
https://arxiv.org/pdf/hep-th/0208013.pdf
Last edited:
Originally Posted By: Schmoe
Oh boy.....the universe is flat? I guess I'm thinking like a piece of sheetrock is flat, but we can view space 360 degrees....so it's expanding or contracting, depending on which is correct, on a linear plane? I ain't seeing that.
AFAIK, "flat" means its geometry is basically the same everywhere. There are local distortions due to gravity, but on large scales it's very even in all directions.
Oh boy.....the universe is flat? I guess I'm thinking like a piece of sheetrock is flat, but we can view space 360 degrees....so it's expanding or contracting, depending on which is correct, on a linear plane? I ain't seeing that.
AFAIK, "flat" means its geometry is basically the same everywhere. There are local distortions due to gravity, but on large scales it's very even in all directions.
Originally Posted By: d00df00d
Originally Posted By: Schmoe
Oh boy.....the universe is flat? I guess I'm thinking like a piece of sheetrock is flat, but we can view space 360 degrees....so it's expanding or contracting, depending on which is correct, on a linear plane? I ain't seeing that.
AFAIK, "flat" means its geometry is basically the same everywhere. There are local distortions due to gravity, but on large scales it's very even in all directions.
That's correct, here is a NASA page on the Wilkinson Microwave Anisotropy Probe (WMAP) results:
https://map.gsfc.nasa.gov/universe/uni_shape.html
Also from the even more sensitive Planck spacecraft:
Quote:
The Planck Consortium also find the universe is topologically flat to a very high degree, with an upper limit of 1/2 of 1% deviation from flatness at large scales. This is an impressive observational result.
Originally Posted By: Schmoe
Oh boy.....the universe is flat? I guess I'm thinking like a piece of sheetrock is flat, but we can view space 360 degrees....so it's expanding or contracting, depending on which is correct, on a linear plane? I ain't seeing that.
AFAIK, "flat" means its geometry is basically the same everywhere. There are local distortions due to gravity, but on large scales it's very even in all directions.
That's correct, here is a NASA page on the Wilkinson Microwave Anisotropy Probe (WMAP) results:
https://map.gsfc.nasa.gov/universe/uni_shape.html
Also from the even more sensitive Planck spacecraft:
Quote:
The Planck Consortium also find the universe is topologically flat to a very high degree, with an upper limit of 1/2 of 1% deviation from flatness at large scales. This is an impressive observational result.
Originally Posted By: MolaKule
I teach QM in Physical Chemistry. I'll be glad to entertain any questions.
I have one. How do you peel off all the math for the chemists?
Sorry, couldn't resist. Now, I can't give computational chemists too hard of a time.
I remember one physicist I knew teaching something called physics for arts students, not requiring any math. I noted that physics without math is a bunch of hand waving, and he says yes, basically, that's what the class was.
I teach QM in Physical Chemistry. I'll be glad to entertain any questions.
I have one. How do you peel off all the math for the chemists?
I remember one physicist I knew teaching something called physics for arts students, not requiring any math. I noted that physics without math is a bunch of hand waving, and he says yes, basically, that's what the class was.
Originally Posted By: Garak
I remember one physicist I knew teaching something called physics for arts students, not requiring any math. I noted that physics without math is a bunch of hand waving, and he says yes, basically, that's what the class was.
Everything comes down to math if you look at it long enough. One of my daughters is a graduate student in music, and her music theory classes are all math. It seems like everything can be eventually reduced to some branch of mathematics including art.
I remember one physicist I knew teaching something called physics for arts students, not requiring any math. I noted that physics without math is a bunch of hand waving, and he says yes, basically, that's what the class was.
Everything comes down to math if you look at it long enough. One of my daughters is a graduate student in music, and her music theory classes are all math. It seems like everything can be eventually reduced to some branch of mathematics including art.
Absolutely. That's why I was good at music theory as a kid, but don't ask me to play an instrument.
Everything does boil down to math. Unfortunately, most of society doesn't know enough math (nor do they need to know enough math) to appreciate the fact, and all the little intricacies.
I remember my god daughter complaining in late elementary school/early high school math about having to memorize formulas, notably for the volume of a sphere. Why do we have to memorize that? Why can't we be shown how it works? I dug out the three page derivation with the triple integral over the parametric equations and showed her. The question answered itself.
I remember my god daughter complaining in late elementary school/early high school math about having to memorize formulas, notably for the volume of a sphere. Why do we have to memorize that? Why can't we be shown how it works? I dug out the three page derivation with the triple integral over the parametric equations and showed her. The question answered itself.
+1 on music. Broke it down for my daughter for percussion, which I've played for years, and all quarters, eights, fifths, etc. etc. all add up to the time signature of the measure. After that, boy howdy, she took off and started nailing all the hard stuff. amazed me. I wish someone would have sat me down and explained it that way when I was in high school. I struggled with learning note values.
A very good discussion. Thank you all for contributing. Hope more will join with their insights on existence and non-existence. So is the opposite of cogito ergo sum, sum ergo cogito?
yah, not being sentient would make this a non problem. I've learned a lot of things, I think.
MolaKule
Staff member
Originally Posted By: Garak
Originally Posted By: MolaKule
I teach QM in Physical Chemistry. I'll be glad to entertain any questions.
I have one. How do you peel off all the math for the chemists?
Sorry, couldn't resist. Now, I can't give computational chemists too hard of a time.
I remember one physicist I knew teaching something called physics for arts students, not requiring any math. I noted that physics without math is a bunch of hand waving, and he says yes, basically, that's what the class was.
One of the text's we teach from is Engle and Reid's Physical Chemistry.
We try get through by Chapter 19 for the first semester, so Quantum Mechanics coverage is pretty thorough. Here is the coverage for each semester:
Table of Contents
(First Semester)
1 Fundamental Concepts of Thermodynamics
2 Heat, Work, Internal Energy, Enthalpy, and the First Law of Thermodynamics
3 The Importance of State Functions: Internal Energy and Enthalpy
4 Thermochemistry
5 Entropy and the Second and Third Laws of Thermodynamics
6 Chemical Equilibrium
7 The Properties of Real Gases
8 Phase Diagrams and the Relative Stability of Solids, Liquids, and Gases
9 Ideal and Real Solutions
10 Electrolyte Solutions
11 Electrochemical Cells, Batteries, and Fuel Cells
12 From Classical to Quantum Mechanics
13 The Schrödinger Equation
14 The Quantum Mechanical Postulates
15 Using Quantum Mechanics on Simple Systems
16 The Particle in the Box and the Real World
17 Commuting and Noncommuting Operators and the Surprising Consequences of Entanglement
18 A Quantum Mechanical Model for the Vibration and Rotation of Molecules
19 The Vibrational and Rotational Spectroscopy of Diatomic Molecules
(Second Semester)
20 The Hydrogen Atom
21 Many-Electron Atoms
22 Quantum States for Many- Electron Atoms and Atomic Spectroscopy
23 The Chemical Bond in Diatomic Molecules
24 Molecular Structure and Energy Levels for Polyatomic Molecules
25 Electronic Spectroscopy
26 Computational Chemistry
27 Molecular Symmetry
28 Nuclear Magnetic Resonance Spectroscopy
29 Probability
30 The Boltzmann Distribution
31 Ensemble and Molecular Partition Functions
32 Statistical Thermodynamics
33 Kinetic Theory of Gases
34 Transport Phenomena
35 Elementary Chemical Kinetics
36 Complex Reaction Mechanisms
Originally Posted By: MolaKule
I teach QM in Physical Chemistry. I'll be glad to entertain any questions.
I have one. How do you peel off all the math for the chemists?
I remember one physicist I knew teaching something called physics for arts students, not requiring any math. I noted that physics without math is a bunch of hand waving, and he says yes, basically, that's what the class was.
One of the text's we teach from is Engle and Reid's Physical Chemistry.
We try get through by Chapter 19 for the first semester, so Quantum Mechanics coverage is pretty thorough. Here is the coverage for each semester:
Table of Contents
(First Semester)
1 Fundamental Concepts of Thermodynamics
2 Heat, Work, Internal Energy, Enthalpy, and the First Law of Thermodynamics
3 The Importance of State Functions: Internal Energy and Enthalpy
4 Thermochemistry
5 Entropy and the Second and Third Laws of Thermodynamics
6 Chemical Equilibrium
7 The Properties of Real Gases
8 Phase Diagrams and the Relative Stability of Solids, Liquids, and Gases
9 Ideal and Real Solutions
10 Electrolyte Solutions
11 Electrochemical Cells, Batteries, and Fuel Cells
12 From Classical to Quantum Mechanics
13 The Schrödinger Equation
14 The Quantum Mechanical Postulates
15 Using Quantum Mechanics on Simple Systems
16 The Particle in the Box and the Real World
17 Commuting and Noncommuting Operators and the Surprising Consequences of Entanglement
18 A Quantum Mechanical Model for the Vibration and Rotation of Molecules
19 The Vibrational and Rotational Spectroscopy of Diatomic Molecules
(Second Semester)
20 The Hydrogen Atom
21 Many-Electron Atoms
22 Quantum States for Many- Electron Atoms and Atomic Spectroscopy
23 The Chemical Bond in Diatomic Molecules
24 Molecular Structure and Energy Levels for Polyatomic Molecules
25 Electronic Spectroscopy
26 Computational Chemistry
27 Molecular Symmetry
28 Nuclear Magnetic Resonance Spectroscopy
29 Probability
30 The Boltzmann Distribution
31 Ensemble and Molecular Partition Functions
32 Statistical Thermodynamics
33 Kinetic Theory of Gases
34 Transport Phenomena
35 Elementary Chemical Kinetics
36 Complex Reaction Mechanisms
Last edited:
Originally Posted By: kschachn
Originally Posted By: Garak
I remember one physicist I knew teaching something called physics for arts students, not requiring any math. I noted that physics without math is a bunch of hand waving, and he says yes, basically, that's what the class was.
Everything comes down to math if you look at it long enough. One of my daughters is a graduate student in music, and her music theory classes are all math. It seems like everything can be eventually reduced to some branch of mathematics including art.
It's not that everything comes down to math, since all of these things including music existed long before math did.
Math only provides a simple way of modeling things.
Originally Posted By: Garak
I remember one physicist I knew teaching something called physics for arts students, not requiring any math. I noted that physics without math is a bunch of hand waving, and he says yes, basically, that's what the class was.
Everything comes down to math if you look at it long enough. One of my daughters is a graduate student in music, and her music theory classes are all math. It seems like everything can be eventually reduced to some branch of mathematics including art.
It's not that everything comes down to math, since all of these things including music existed long before math did.
Math only provides a simple way of modeling things.
MolaKule
Staff member
Originally Posted By: Wolf359
Do you have a section that covers gravity waves?
If that question was directed to me, no.
Gravity waves are covered in Astronomy and Cosmology courses.
Do you have a section that covers gravity waves?
If that question was directed to me, no.
Gravity waves are covered in Astronomy and Cosmology courses.
MolaKule
Staff member
Originally Posted By: fdcg27
It's not that everything comes down to math, since all of these things including music existed long before math did.
Math only provides a simple way of modeling things.
But you have to be proficient in mathematics in order to get a good grasp of the Physics.
It's not that everything comes down to math, since all of these things including music existed long before math did.
Math only provides a simple way of modeling things.
But you have to be proficient in mathematics in order to get a good grasp of the Physics.
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