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Author Topic:   gravity
AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


Message 3 of 81 (688077)
01-18-2013 9:42 PM
Reply to: Message 1 by shadow71
01-18-2013 7:08 PM


Start with some basic research first.
Here
When you have questions outside the most basic come on back. There is a lot of knowledge on the subject in the membership.

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AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


Message 6 of 81 (688095)
01-19-2013 1:11 AM
Reply to: Message 4 by Dogmafood
01-18-2013 11:53 PM


Re: Equivalence Principal
If the attractive force of gravity is proportional to the mass of two bodies, why does an object of greater mass not fall quicker?
Your talking about two objects falling in earth's gravity well. There is a third body in there: the earth.
Each dropped object is in free fall within earths gravity well. Each object will drop with the same acceleration. That is the Acceleration of Gravity.
The proportional mass part comes in from the mass of object 1 (an apple) vis-a-vis the earth, totally independent of the mass of the other dropped object (a sledge hammer). Both exert an attractive force on the other but since the earth is much more massive the force of the apple on the earth is negligible while the force of the earth on the apple is considerable thus the earth moves the apple further, but not faster, than the apple moves the earth.
The same for the 15 lb sledge hammer. The sledge is exerting a more powerful force on the earth than the apple did due to its greater mass but is still negligible considering the difference in mass between it and the earth thus the earth is also moving the heavier sledge further, but not faster, than the sledge moves the earth.
If all you had in the universe were the apple and the sledge hammer then the two would each exert a force on the other with the sledge having the greater force thus moving the apple further, but not faster, than the apple moves the sledge.

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AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


Message 14 of 81 (688122)
01-19-2013 9:26 AM
Reply to: Message 8 by NoNukes
01-19-2013 2:31 AM


Re: Equivalence Principal
Maybe I am misreading this, but your comment seems off.
Then it probably is. But no matter. There was a Rocky & Bullwinkle where Dudley Do-Right jumps from the bath and runs down the street yelling "Y-rika" instead of U-rika. The voice over explained that it was OK since Dudely know what he ment. I claim the same privilege.

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AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


Message 17 of 81 (688172)
01-20-2013 7:52 AM
Reply to: Message 12 by shadow71
01-19-2013 9:14 AM


he leaves me with the impression gravity is metaphysical in origin.
Dr. Schroeder's musings on forcing his science to justify his religion are not new. Creationists have been down that path many times. It is not surprising that his views strike a chord with you.
To counterpoint, have you read other scientists, some maybe without a pre-determined religious goal? Brian Greene? Michael Berry? Lee Smolin?
If you want a real head trip try Lisa Randall's Warped Passages. Her views on gravity are quite interesting and you will come away from that one with quite a different perspective on the whole universe.
[in edit]
Have you looked at General Relativity?
At this time this is our best, most tested and successful, theory of gravity, how it works, where it comes from. Nothing magical about it. Just follow the contours of space-time.
Edited by AZPaul3, : No reason given.

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AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


Message 25 of 81 (688210)
01-20-2013 7:39 PM
Reply to: Message 24 by NoNukes
01-20-2013 5:04 PM


I'm probably not going to have any serious comment until I am more familiar with what Shroeder is discussing.
You might be interested in this critique of Schroeder's The Hidden Face of God
It goes into some detail on his arguments. It is not flattering, but then the errors in fact that Schroeder gives are a bit disconcerting since he is a physicist.
I found this combined review of his first 3 books enlightening. Same critique of his errors of physics facts. My feeling is that Schroeder is a typical religionist trying to shoehorn physics into some support of biblical efficacy.

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 Message 26 by shadow71, posted 01-20-2013 7:59 PM AZPaul3 has replied
 Message 54 by zi ko, posted 01-25-2013 11:21 AM AZPaul3 has replied

  
AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


(1)
Message 27 of 81 (688217)
01-20-2013 8:25 PM
Reply to: Message 26 by shadow71
01-20-2013 7:59 PM


Did you read the review? Do you see the arguments against Schroeder? Do you see the factual errors highlighted in his arguments?
quote:
I guess I am looking for some studies or opinions based on scientific evidence why Schroeder may be wrong.
Well, there you go. Enjoy.

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AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


Message 36 of 81 (688327)
01-21-2013 9:16 PM
Reply to: Message 32 by shadow71
01-21-2013 3:54 PM


Schroeder's religious treatment strikes a comfortable note with your own religious views. But you did ask for competing views which would necessitate non-religious ones thus not as comfortable for you.
You can reject the sources I presented citing a bias that is not comfortable for you. This is OK.
But you need to be aware that the sources I gave pointed out Schroeder's errors of logic as well as his errors in physics facts. There are only two reasons I can fathom why an MIT physicist would make these errors. He is an incompetent physicist despite the MIT affiliation or he is misusing physics, in essence lying, to justify his predetermined conclusions.
You can, of course, ignore these errors and their implications on the efficacy of Schroeder's hypothesis. You are then not searching for intellectual answers but for emotional confirmation. The knowledgeable folks on this forum will not be able to help you with this. You may want to ask your questions in a less science-oriented forum.

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 Message 44 by shadow71, posted 01-23-2013 12:06 PM AZPaul3 has replied

  
AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


(2)
Message 50 of 81 (688600)
01-23-2013 7:49 PM
Reply to: Message 44 by shadow71
01-23-2013 12:06 PM


quote:
On page 38 of his book Schroeder suggested the following equation:
hf=mc2.......................(1)
where h is Planck's constant, f is the frequency of deBroglie's wave for a particle, m is the particle's mass and c is speed of light.
Whereas equation (1) is absurd, it is easy to figure out how Schroeder derived it. He read somewhere about the following correct equations [4]:
1) E=hf.........................(2)
and 2) E=mc2.......................(3)
Equation (2) was originally suggested by Planck (in 1900) for the quantum of energy emitted by a black body. In 1905, Einstein applied that equation to the energy of photons regardless of whether they are emitted, traveling or absorbed by a material. In 1923 de Broglie suggested to expand the application of that equation to all particles, either massless as a photon or having a rest mass m. As to equation (3), it is probably the most widely known equation of science derived by Einstein in 1905 as a part of his special theory of relativity.
In both equations (2) and (3) E denotes energy of a particle. Obviously lacking proper understanding of these two equations, and seeing the same letter E on the left side of both, Schroeder mechanically combined the equations (2) and (3) into one equation (1).
Unfortunately for Schroeder, he obviously did not know that E in equation (2) and E in equation (3), while both denoting the energy of a particle, actually denote two different energies. E in equation (2) denotes the variable energy of a moving particle, related to that particle's momentum. E in equation (3) is a constant for a given particle, which denotes the so-called rest energy. These two types of particle's energy have little to do with each other. The absurdity of Schroeder's equation (1) is immediately obvious when we notice that it equalizes a variable quantity to a constant. Indeed, the frequency f of de Broglie wave for a particle is not a fixed constant but depends on the particle's momentum, i.e. on its velocity.
.
.
.
The equation (1) is not the only error in Schroeder's new book. However, it seems sufficient to limit the demonstration of the inaccuracies in Schroeder's literary production to the above examples.
Since Schroeder's insufficient competence in physics, which is his professional field, is obvious, what credibility can be given to his lengthy discourse on molecular biology which is not his professional field?
You didn't read the reviews, did you.
This is not some difference in philosophy or world view. This is a glaring error of fact in known physics; an absurdity that a competent physicist could not possibly make.
Don't give me any of this "errors are not black or white or accepted by all physicists" bullshit. This is just flat out incompetent. Period.
Schroeder is not a resource you want to use. There must be a competent physicist on your side of the street somewhere. I suggest you drop Schroeder and go find him.

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AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


Message 58 of 81 (688820)
01-25-2013 5:59 PM
Reply to: Message 55 by NoNukes
01-25-2013 11:28 AM


horta?

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AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


Message 59 of 81 (688821)
01-25-2013 6:07 PM
Reply to: Message 54 by zi ko
01-25-2013 11:21 AM


Scot Osser' s opinion in his Shroeder's critique, that energy could be the result of matter or that matter and energy are equivalent as regards sequence, seems to me wrong.As we go from biggest to smallest, e.g from peripheral to central, from the end result to the beggining,we see matter ending to quantons e.g energy.Sroeder's view seems more propable.
Emotional distaste and what "seems" right or wrong to you or me make no difference. This is one reason why actual competent physicists determine these things, not amateurs.

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AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


Message 61 of 81 (688910)
01-26-2013 12:51 PM
Reply to: Message 60 by NoNukes
01-26-2013 10:04 AM


It was a play off of golden number's "mushroom". My nuke looked more like the horta, a creature from Star Trek. It really had no impact and added nothing to the discussion. My bad.
So as to make amends and redeem myself allow me to contribute this:
What form would energy without matter take?
You mentioned energy fields. Photons would be an excellent example. All wavelengths of the EM spectrum.
Edited by AZPaul3, : No reason given.

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AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


Message 77 of 81 (689039)
01-27-2013 5:40 PM
Reply to: Message 65 by cavediver
01-27-2013 6:50 AM


hf=mc2
h=mc2/f
In the case of a photon then planck's constant disappears?
λ = h/mc doesn't appear to be a suitable rewrite for f=mc2/h
Edited by AZPaul3, : No reason given.
Edited by AZPaul3, : No reason given.

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Replies to this message:
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AZPaul3
Member
Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


Message 79 of 81 (689047)
01-27-2013 7:31 PM
Reply to: Message 78 by cavediver
01-27-2013 6:21 PM


Of course.
Thanks for the kick.
------------------------------------
A few hours later:
You mentioned Compton. The wave length of the scattered photon would be constant given the constant rest mass of the particle.
So if we look at the electron, a known constant rest mass, then Schroeder's equation ends up with 3 constants (m, c, h) and the one variable (f) to be calculated. f would also be constant for any specific mass.
So all electrons will have only the one frequency. But we know this is not right. It is still absurd.
Edited by AZPaul3, : much thinking.
Edited by AZPaul3, : No reason given.

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