All Questions
Tagged with time coordinate-systems
85
questions
-3
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1
answer
71
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Does quantum entanglement arise from perpendicular time vectors? [closed]
From what I understand, "quantum entanglement" is a phenomenon where certain information travels instantly between entangled particles, regardless of distance in space.
When thinking of ...
- 413
4
votes
1
answer
676
views
Intuitive explanation of COSMIC TIME?
I came across the following statement, while studying a Newtonian model for cosmic expansion:
"If $R(t)$ is the scaling factor, we can define the Hubble parameter as $H(t)=\frac{\dot{R(t)}}{R(t)}...
- 152
0
votes
2
answers
558
views
Can we define time as a field? [closed]
The main objective is, can we relate time in terms of a field, I know time differs in many properties from an usual field. But I always imagine time as an forward moving field and we all know it is ...
- 47
8
votes
1
answer
357
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The synchronized clocks on earth's surface: at which observer's rate are they beating?
From what I understand, the time rates (I'm not speaking about absolute times) of all clocks on earth's surface are synchronized. This means that, say, a mobile phone's clock is generally not beating ...
- 3,753
0
votes
1
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243
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Is proper time the affine parameter in general relativity?
If we consider the proper time, $\gamma d\tau = dt$, and 4-velocity $v^{\mu}=\tfrac{dx^{\mu}}{d\tau}=(\gamma c,\gamma \vec{v})$ of a particle with velocity $\vec{v}$, then the corresponding space-time ...
- 391
1
vote
2
answers
106
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In spacetime time is a coordinate. Does it mean there is a single objective timeline for the Universe?
If every event can be defined with x, y, z, t coordinates - does it mean all events with the same t are composing the whole Universe at the moment t?
0
votes
6
answers
388
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Time dilation and understanding which is $\Delta t$ and which is proper time $\tau$
In the textbook that we are using, the definition for proper time $\tau$ is the interval between two events, as measured by an observer who is at rest with the two events. The definition for $\Delta t$...
4
votes
2
answers
229
views
Difference between proper time and coordinate time
Lately, I have been studying General Relativity, and I am very confused about the difference between proper time ($\tau$) and coordinate time ($t$).
Also, whenever we write any line element given a ...
- 299
16
votes
3
answers
2k
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Why is clock synchronisation such a big deal in physics?
I was reading Classical Mechanics : The theoretical minimum by Leonard Susskind, and he says
Assume that two clocks at different places can be synchronised.
I don't understand why one should do that....
- 430
2
votes
1
answer
131
views
Why is cosmological time unique?
According to the definition I have encountered for the concept of cosmological time, it is defined in the following way:
The cosmological principle states that, at each location in the universe, it ...
- 293
1
vote
2
answers
355
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How can you read from a phase space diagram how quickly a path gets traversed?
I'm learning about Hamiltonian mechanics and it is quite interesting. However I'm trying to understand how to see how quickly a path in phase space gets traversed. How do you read from a phase space ...
- 2,035
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2
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239
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Is time measured, a property of the object or of the frame in which the object is observed? [closed]
I'm a bit confused behind the idea of the twin paradox. Suppose we fix a given frame, then in this given frame, wouldn't all objects read the same time making twin paradox meaningless as everyone ...
- 7,980
1
vote
2
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274
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Proper time in a curved space
In special relativity we've the invariant
$$
d s^2=-d t^2 +d x^2 + d y^2+d z^2
$$
For a clock moving along the worldline in question the above equation reduces to $\begin{aligned} d s^2=&-d t^2\...
- 1,270
2
votes
4
answers
220
views
A doubt regarding $L=T-V$ and explicit time dependence
Edit: After having some clarity, I chose to write an answer instead of editing the question itself. Scroll down to read it after reading the problem that follows.
Let's say $\vec{r}=\vec{r}(q_1,q_2 ......
user292464
0
votes
1
answer
142
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Physical meaning of a time dependent $g_{00}$
I have been studying Birkhoff's theorem and, separately, co-moving coordinates.
One of the final steps in Birkhoff's theorem (from Weinberg's GR pg. 337) is to redefine the time coordinate to absorb ...
- 57