Why two mass attracts each other?

[ash64449]

It is very straightforward..

Can you show through equivalence principle that acceleration can be seen as repulsive too?

And i Agree with Marcus too... same as what i said.But expressed very differently.

 

[ash64449]

And If you don't know what i mean.

Look at this article: http://www.einstein-online.info/spotlights/equivalence_principle

See how gravity(attractive) is termed as indistinguishable from acceleration.

Try to build and show that gravity can be repulsive through the experiment shown in this article.

If you are able to build up a repulsive "force",then acceleration can indeed be indistinguishable from it and you can say that gravity is repulsive.

If you can't build,then gravity is attractive.

And according to me,it is impossible to build up a repulsive force from this thought experiment.

So Gravity is always attractive.

 

[hansda]

Can you show through equivalence principle that acceleration can be seen as repulsive too?

What point you are trying to prove here?

 

[ash64449]

What point you are trying to prove here?

that you cannot do that following thing that i asked you to do. so gravity can only be attractive...

What is there to understand?? It is very easy.

 

[hansda]

And If you don't know what i mean.

Look at this article: http://www.einstein-online.info/spotlights/equivalence_principle

See how gravity(attractive) is termed as indistinguishable from acceleration.

Try to build and show that gravity can be repulsive through the experiment shown in this article.

If you are able to build up a repulsive "force",then acceleration can indeed be indistinguishable from it and you can say that gravity is repulsive.

If you can't build,then gravity is attractive.

And according to me,it is impossible to build up a repulsive force from this thought experiment.

So Gravity is always attractive.

Do you know, "what is precession?". Do you think precession is attractive?

 

[ash64449]

Please read that article very carefully..

If you are really into finding the answer to the question,you must carefully understand each and every line of that article.

 

[ash64449]

Do you know, "what is precession?". Do you think precession is attractive?

where did you get the word?

If you did get that word from the article. Quote the sentence containing the word.

 

[hansda]

Please read that article very carefully..

If you are really into finding the answer to the question,you must carefully understand each and every line of that article.

Do you know, our "Universe is expanding"?

 

[hansda]

where did you get the word?

If you did get that word from the article. Quote the sentence containing the word.

See about perihilion precession here.

 

[eram]

All this "time dilation" "length contraction" talk got me to thinking about "contraction"( pulling-in ) of the womb too induce a dilation( expanding-out ) of the cervix to allow baby exit the womb. This is a pulling-in force that leads to a pushing-out force.

Maybe I stated this in reference to gravity in another post. Gravity is a pulling-in( mass-attractive ) force--- see non-observed graviton :--) ---and as a result of gravities pulling-in, there is a resultant pushing-out reaction called dark energy or cosmological constant.

If I recall correctly, the new news out regarding Wienstiens TOEeveything, is that there is not repulsive, cosmological constant ergo no dark energy. He apparently believes that the observed Universe we see is just a flat part of a greater Universe, and this flatness is what cause the appearance of a cosmological constant or dark energy.

So it appears to me, that, just as some believe that gravity is purely a geometrical subcataory of mathematics, I believe that, the cosmological constant is a resultant of spactime contraction, and similar to the situation with the fetus/baby exiting womb to become independent baby.

I'm curious to see how Wienstien handles the constancy of speed-of-radiation and gravity( mass-attraction ) as a force of nature or just mathematical subcategory of geometry.

My feeling is that there exists tubes of nature that feed into larger containment chambers--- ex polyhedral, spherical whatever ---that then have exit tubes/pathways canals etc.....on both the macro, medio, micro and ultra-micro scales of existence.

If mass-attraction did not exist, Universe would not exist. Time/accelearation(?) dilation and space/length contraction?

How do we simplify this for the common human? If we say that speed-of-radiation is like time standing still--- see Brian Greens 2D slices-of-Universe ---then I and many others have had the perception of experiencing that time stopped or extended.

I guess it is like and experience of very long moment between two seconds. So was that due to a contraction of space, or acceleration of chemistry?

r6

Dude, that is really random gibberish.

I think you should stick to poetry.

 

[Markus Hanke]

In fact "repulsive force" is also observed in nature in the form of "casimiri effect".

See these papers. 1. 2.


So, there is also a possibility of "repulsive force" between two mass.

The Casimir effect is quantum mechanical in nature, and a result of vacuum polarisation. It has nothing whatsoever to do with masses, and cannot be extended to the macroscopic domain. It has therefore no relevance to GR.

 

[hansda]

The Casimir effect is quantum mechanical in nature, and a result of vacuum polarisation. It has nothing whatsoever to do with masses, and cannot be extended to the macroscopic domain. It has therefore no relevance to GR.

1. "Casimir Effect" has relevance with GR though it does not follow GR. See this article.

Here is a quote from the article:

Although this trick works, and gives answers in agreement with experiment, the problem of an infinite vacuum energy is a serious one. Einstein's theory of gravitation implies that this energy must produce an infinite gravitational curvature of spacetime--something we most definitely do not observe. The resolution of this problem is still an open research question.

2. Effect of "precession" as in 'perihelion precession of Mercury' also can be considered as repulsive to some extent.

 

[Markus Hanke]

1. "Casimir Effect" has relevance with GR though it does not follow GR. See this article.

This article says nothing about "repulsion", and is therefore not relevant to the discussion.

2. Effect of "precession" as in 'perihelion precession of Mercury' also can be considered as repulsive to some extent.

No it can't. The precession is a consequence of the geometry of the planet's orbit, and has nothing to do with either attraction or repulsion.

 

[1100f]

2. Effect of "precession" as in 'perihelion precession of Mercury' also can be considered as repulsive to some extent.

On the contrary, when you look at the Schwarzchild solution of the Kepler problem at weak fields regime (like for the orbit of Mercury), you find that the effective potential energy gets an extra term which causes the precession and this extra term is like an attractive one, not a repulsive one.
Look for example at http://en.wikipedia.org/wiki/Two-body_problem_in_general_relativity in the part named "Effective radial potential energy " (about in the middle of the page).

 

[ash64449]

Do you know, our "Universe is expanding"?

Yeah.. of course. Why do you ask that? I think we can get that from Einstein's Field Equations itself..

 

[ash64449]

See about perihilion precession here.

And what is this has to do with the discussion?

 

[ash64449]

Handsa, you won't get answer of you didn't reply to my questions at all!!

 

[hansda]

No it can't. The precession is a consequence of the geometry of the planet's orbit, and has nothing to do with either attraction or repulsion.

I think this is a very wrong statement, you made. Can there be any "precession" without any application of force? This 'precession' is accounted correctly by GR only.

 

[hansda]

On the contrary, when you look at the Schwarzchild solution of the Kepler problem at weak fields regime (like for the orbit of Mercury), you find that the effective potential energy gets an extra term which causes the precession and this extra term is like an attractive one, not a repulsive one.
Look for example at http://en.wikipedia.org/wiki/Two-body_problem_in_general_relativity in the part named "Effective radial potential energy " (about in the middle of the page).

The first two terms are well-known classical energies, the first being the attractive Newtonian gravitational potential energy and the second corresponding to the repulsive "centrifugal" potential energy; however, the third term is an attractive energy unique to general relativity. As shown below and elsewhere, this inverse-cubic energy causes elliptical orbits to precess gradually by an angle δφ per revolution

See the above quote from your wiki reference. The "unique attractive force due GR" causes additional precession and due to this the planet Mercury takes "additional time" for completion of its orbit. This "additional time" suggets the effect is repulsive. [note: behaviour of precession is not linear.]

 

[hansda]

Do you know, our "Universe is expanding"?

Yeah.. of course. Why do you ask that? I think we can get that from Einstein's Field Equations itself..

HOW?

See about perihilion precession here.

And what is this has to do with the discussion?

Due to this "perihelion precession", the planet Mercury takes "longer time" to complete its orbit. This suggets a repulsive effect.