All Questions
10
questions
0
votes
0
answers
72
views
How to mathematically describe the process of spacetime curvature?
I guess as a result of the energy-momentum tensor $T_{\mu\nu}$ coupling to a flat Minkowski metric, $\eta_{\mu\nu}$, the flat metric can become that of a curved spacetime, $g_{\mu\nu}$. How can one ...
- 357
5
votes
0
answers
127
views
Is it possible to create a Nil geometry in real spacetime according to general relativity? (What metrics are possible in the real world?)
Background
I've heard that it is possible to construct a Penrose triangle in the 3D geometry Nil. And I wondered: Can we build a Penrose triangle in the real world if spacetime is appropriately ...
0
votes
2
answers
265
views
Are the Einstein field equations the Equations of Motion for matter?
I'm learning general relativity and eventually I hope to understand the Einstein field equations $$G_{\mu\nu}=\kappa T_{\mu\nu}$$ in full mathematical detail.
I wonder whether they describe the ...
- 1,477
6
votes
1
answer
254
views
Linear Momentum in General Relativity
My question is, does a particle moving in a straight line at constant velocity through empty space create "frame dragging" that would tend to entrain other bodies in the direction of its ...
- 9,500
2
votes
0
answers
84
views
Through what exact mechanism is the stress energy tensor bending spacetime?
In the Einstein field equations the metric related quantities are on one side, and the stress-energy tensor on the other.
What is the deeper mechanism of how nature actually implements this ...
- 101
4
votes
1
answer
849
views
Different signatures of the metric in Einstein field equations
Throughout the GR lectures, we have always used (- , + , + , +) signature for the metric tensor but in some chapters it was switched to (+ , - , - , -) and immediately after that Einstein field ...
- 3,464
3
votes
2
answers
681
views
Solutions to Einstein Field Equations where $T_{\mu \nu} = 0$
My Level/Background:
I have just completed my first year of undergrad. In high school, I completed AP Physics C Mechanics and Electricity and Magnetism. In my first year of undergrad, I completed a ...
- 822
1
vote
1
answer
67
views
Are energy and momentum imposed by purely geometrical properties of spacetime?
If we defined spacetime as a purely geometrical (not physical) structure of the kind that is in general relativity (a 4-dimensional Lorentzian manifold), would it automatically have properties that ...
0
votes
2
answers
261
views
How does one approach negative curvature in the Einstein Field Equations?
Everyone talks about positive curvature when they talk about the EFE, and for good reason. I'd just like to know what would change in the equation if it accounted for negative curvature of spacetime ...
user250721
1
vote
1
answer
244
views
Can spacetime be defined by the requirement that the physical laws are simple?
When I was student I was told that time is defined by the requirement that the physical laws are simple. For example, in classical mechanics time can be defined by the requirment that the velocity of ...
- 23