gravity on electron

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recca02

Joined Apr 2, 2007
1,211
what else does it act on considering everything is made up of electron, proton and neutron is it not?
sure it does.
however since their masses are so negligible, gravitational force is negligible on them .So if only a separate electron is considered for study of its motion in electric field or similar thing effects of gravity aren't considered.
 

Dave

Joined Nov 17, 2003
6,960
Does force of gravity acts on electron ,proton ,neutron?
They all have mass, and therefore will be subject to the effects of gravity. recca02 has explained how in micro-scale situations the effects are negligible.

Dave
 

Salgat

Joined Dec 23, 2006
215
Funny thing is, gravity is pretty much impossible to measure at the atomic scale.
 

recca02

Joined Apr 2, 2007
1,211
so ,here is a tricky one,
does gravity act on light wave (photons)?
remember black hole (not the one in ozone layer)!
 

thingmaker3

Joined May 16, 2005
5,073
I thought the black hole event horizon was due to space itself becoming curved, rather than because of photons responding to gravity.
 

Papabravo

Joined Feb 24, 2006
12,301
In classical physics, the mass of the photon is zero and therefore has no gravitational atraction to other masses.

It does travel at the speed of light and according to special relativity the SQRT(1 - (v/c)^2) in the demominator goes to zero making the relatavistic mass infinite.

It takes general relativity to resolve the conundrum:
From the Wikipedia article on the "Photon"

Since photons contribute to the stress-energy tensor, they exert a gravitational attraction on other objects, according to the theory of general relativity. Conversely, photons are themselves are affected by gravity; their normally straight trajectories may be bent by warped spacetime, as in gravitational lensing, and their frequencies may be lowered by moving to a higher gravitational potential, as in the Pound-Rebka experiment. However, these effects are not specific to photons; exactly the same effects would be predicted for classical electromagnetic waves
 

recca02

Joined Apr 2, 2007
1,211
thanks for the reply mr thingmaker & mr p.b.,
i m a little subtle(dense) when it comes to relativity ,
havent gone beyond time dilation proof, twin paradox and some other basic concepts.
actually i knew that gravity acts on photons at their high speed and that it wud req relativity to understand it :)


will do some study of the tensor quantity stress-energy.

btw : i said photons to refer to em waves
 

Dave

Joined Nov 17, 2003
6,960
so ,here is a tricky one,
does gravity act on light wave (photons)?
remember black hole (not the one in ozone layer)!
I think this comes back to the need for a theroy of gravity, which from the point of view of agreement between Relativity and Quantum Mechanics is quite a way off.

Since photons contribute to the stress-energy tensor, they exert a gravitational attraction on other objects, according to the theory of general relativity.
Interesting. I knew that EM waves (of which visible light is one form) responded to the effects of gravity as described in later part of the above referenced article. Relatvity predicts so many things about the physical world, it is a truely fantastic piece of science.

Dave
 

Reshma

Joined Mar 11, 2007
54
The force of gravitation is 10^(-38) times weaker than the strong nuclear force. So usually, gravity is neglected when considering elementary particles.
 

Dave

Joined Nov 17, 2003
6,960
The force of gravitation is 10^(-38) times weaker than the strong nuclear force. So usually, gravity is neglected when considering elementary particles.
Whilst true in a practical sense...

Does force of gravity acts on electron ,proton ,neutron?

Significantly - No.

Actually - Yes.

Dave
 

FredM

Joined Dec 27, 2005
124
What we need is not another Einstien.. We need another Darwin.. A Darwin who will find a unifying theory for Physics..
It stuns me that Biology (Evolution) has managed (thanks to one man) to progress continuously (no massive re-writes and no major contradictions) and has stood the test of every new discovery (What powers the sun, DNA, to name but 2)..
But Physics limps along, disabled by a dispersion of incohesive 'laws' hypotheses and theories, and incomprehensible maths! (LOL)
So - In the light of how 'right' Biology has been, and how naff Physics is, I think I will base my next project on biological components..

Anyone got a spare brain I can borrow?
 

recca02

Joined Apr 2, 2007
1,211
The grass on the other side seems to be greener ,
i do not think darwin's theory are free from exceptions.
 

Dave

Joined Nov 17, 2003
6,960
What we need is not another Einstien.. We need another Darwin.. A Darwin who will find a unifying theory for Physics..
It stuns me that Biology (Evolution) has managed (thanks to one man) to progress continuously (no massive re-writes and no major contradictions) and has stood the test of every new discovery (What powers the sun, DNA, to name but 2)..
But Physics limps along, disabled by a dispersion of incohesive 'laws' hypotheses and theories, and incomprehensible maths! (LOL)
So - In the light of how 'right' Biology has been, and how naff Physics is, I think I will base my next project on biological components..

Anyone got a spare brain I can borrow?
The difference is that physical laws such as those of Einstein are explicitly implied and embedded in very precise and modellable theory, this makes such theories, mathematics etc, open to analysis and subsequently challenges/rejection in ways that evolution cannot be. That's not saying I don't agree with evolution, but whilst apples and pears are fruit they are not directly comparable.

Dave
 

FredM

Joined Dec 27, 2005
124
The difference is that physical laws such as those of Einstein are explicitly implied and embedded in very precise and modellable theory, this makes such theories, mathematics etc, open to analysis and subsequently challenges/rejection in ways that evolution cannot be. That's not saying I don't agree with evolution, but whilst apples and pears are fruit they are not directly comparable.

Dave
I accept the above.. Also, Biology is, in effect, a sub-set of physics.. A truly universal theory would explain everything, and would be able to model everything mathematically - including biological systems.

And we are a long, long way from anything even approaching the above.. But it still seems likely to me that there is some 'simple' piece of the puzzle missing, and it may only take one astute 'insight' (Like Darwins) for most of the pieces to 'clik' into place..
 

Mike M.

Joined Oct 9, 2007
104
I accept the above.. Also, Biology is, in effect, a sub-set of physics.. A truly universal theory would explain everything, and would be able to model everything mathematically - including biological systems.

And we are a long, long way from anything even approaching the above.. But it still seems likely to me that there is some 'simple' piece of the puzzle missing, and it may only take one astute 'insight' (Like Darwins) for most of the pieces to 'clik' into place..
One thing that life follows that the non-living universe doesn't is Phi. Look up 5-sided crystal and the only things you will find are DNA and man-made objects. A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions............DNA fits that definition. Biology is a whole different ballpark that requires certain ascertations that don't apply to a universe without life. Fusion of life with the non-living universe is going to be quite a task.
 

Dave

Joined Nov 17, 2003
6,960
I accept the above.. Also, Biology is, in effect, a sub-set of physics.. A truly universal theory would explain everything, and would be able to model everything mathematically - including biological systems.

And we are a long, long way from anything even approaching the above.. But it still seems likely to me that there is some 'simple' piece of the puzzle missing, and it may only take one astute 'insight' (Like Darwins) for most of the pieces to 'clik' into place..
I fully concur, in fact I doubt we would really get there but that is a whole other debate.

Dave
 
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