Unifying GR + EM: Inflation & Gravity Effects

[ibysaiyan]

In GR gravity is seen as a property of space-time , curvature. Now we know that sometime after the plank's time we had the universe dominated by radiation ( recombination) as such the rate of inflation was in the range of ~ 10^30 m/s , which as you can see is considerably larger than the VOL ( at about 10^-37 to 10^-35 of a second).

I might be waffling here but if the expansion of the universe itself is not constant due to various parameter , however , the way I see things it has no affect on individual photon speeds.On the other hand I am not sure how gravity field ( or quantum graviton would behave).
I find this in conflict with what GR proposes where gravity doesn't stay constant , and acts as a function of the mass's object.

Can someone shed light over this.

Is this one of the reasons why we are finding it hard to unify GR with E-M ?

P.S: I have more questions in mind which I will ask following on to replies.

-ibysaiyan

 

[bapowell]

In GR gravity is seen as a property of space-time , curvature. Now we know that sometime after the plank's time we had the universe dominated by radiation ( recombination) as such the rate of inflation was in the range of ~ 10^30 m/s , which as you can see is considerably larger than the VOL ( at about 10^-37 to 10^-35 of a second).

Where are you getting your numbers (e.g. 10^30 m/s)? This is not the way that expansion rates are reported. Also, "inflation" refers to a specific epoch during which the early universe underwent accelerated expansion. What is "VOL"?

I might be waffling here but if the expansion of the universe itself is not constant due to various parameter , however , the way I see things it has no affect on individual photon speeds.

That's right. It doesn't and shouldn't.

On the other hand I am not sure how gravity field ( or quantum graviton would behave).
I find this in conflict with what GR proposes where gravity doesn't stay constant , and acts as a function of the mass's object.

You're losing me here. Gravitational fields are described by GR in terms of geometry. The universe is described by a non-static (expanding) spacetime, and GR accommodates this description perfectly fine. Where is the conflict?

 

[Chalnoth]

As an aside, there is no problem whatsoever unifying gravity with electricity and magnetism. The problem is unifying gravity with quantum mechanics.

 

[ibysaiyan]

Where are you getting your numbers (e.g. 10^30 m/s)? This is not the way that expansion rates are reported. Also, "inflation" refers to a specific epoch during which the early universe underwent accelerated expansion. What is "VOL"?

I see what you mean. By VOL I mean't velocity of light.

That's right. It doesn't and shouldn't.You're losing me here. Gravitational fields are described by GR in terms of geometry. The universe is described by a non-static (expanding) spacetime, and GR accommodates this description perfectly fine. Where is the conflict?

I presumed that since heavier masses have more warped space-time curvature , then as a consequence of this the G-field/ wave itself would have a varying propagation speed (sound nonsense to me) , but now that I think of it , a field's strength is proportional to the number of flux lines ( as is the case with B-fields , so perhaps same thing applies to gravity ? )
I don't know how I came with such a vague assumption. Obviously there are various parameters involved at different epochs.

Thanks for the correction (@ Chalnoth) .Of course it's the unification of gravity with QM that is being an issue.

 

[sardar]

Thank you for your question, ibysaiyan. I can provide some insights into the concept of unifying GR and EM through the effects of inflation and gravity.

Inflation is a theoretical period of rapid expansion in the early universe, proposed to explain certain observations such as the uniformity of the cosmic microwave background radiation. In this period, the universe expanded at a rate much faster than the speed of light, as you mentioned. However, it is important to note that this does not violate the speed of light limit, as the expansion of space itself is not bound by this limit.

In GR, gravity is seen as a property of space-time, where the presence of mass and energy causes curvature in the fabric of space-time. This curvature then affects the motion of objects within it, including photons. Therefore, gravity is not seen as a constant force, but rather a function of the masses and energy present in a given space-time.

The issue of unifying GR with EM arises when trying to reconcile the concept of gravity with the other fundamental forces, such as electromagnetism. In GR, gravity is described by the curvature of space-time, while in EM, it is described by the exchange of photons between charged particles. These two theories have been successfully unified in some contexts, such as in the theory of general relativity and the standard model of particle physics. However, there are still open questions and areas of conflict, such as the behavior of gravity at very small scales or in the presence of extremely high energies.

In terms of the effect of gravity on individual photon speeds, it is important to note that the speed of light is a fundamental constant in our universe. This means that it remains constant regardless of the presence of gravitational fields or the expansion of space. However, the path of a photon can be affected by the curvature of space-time, which can lead to phenomena such as gravitational lensing.

In summary, the concept of unifying GR and EM is a complex and ongoing area of research in physics. While there have been successful attempts to do so in certain contexts, there are still open questions and areas of conflict that require further investigation. I hope this sheds some light on your questions and I am happy to continue discussing this topic with you.