Time is defined operationally to be that which is measured by clocks. The SI unit of time is the second, which is defined to be
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1answer
183 views
If you removed every particle from space…? [closed]
I'm trying to find something Einstein (I think) said about time...It
was something like..
"If you removed every particle from space and were left with only one
pocket watch (clock, timepiece?), time ...
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votes
0answers
9 views
1D Kinematics - Relative Motion involving non-inertial frames of reference
I recently came across a question involving non-inertial frames of reference. I didn't quite understand the way it had been solved due to some conceptual confusion regarding certain deductions made to ...
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votes
0answers
38 views
Time ordering and Fermions
Having time ordering operator for fermions, should it reverse sign if it swaps operators with opposite spin variable? In other words should
$T[c_{t_1,\uparrow}c_{t_2,\downarrow}^\dagger]$
return ...
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votes
0answers
27 views
What is the formula for calculating the length of any given day (sunrise to sunset)? [duplicate]
In a specific date what law gives us perfect measurements and how will we measure if latitude is given?
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0answers
34 views
Why there is no operator for time in QM? [duplicate]
Is there one central reason why there is no "Time" operator in QM?
I know this question has been asked before, but I thought I would try to stimulate some fresh thinking.
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votes
0answers
36 views
Can a black hole actually grow, from the point of view of a distant observer? [duplicate]
Possible Duplicate:
Black hole formation as seen by a distant observer
I've read in several places that from the PoV of a distant observer it will take an infinite amount of time for new ...
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votes
0answers
482 views
Create general equation of racing cars with head start [closed]
Cars A and B are racing each other along the same straight road in the following manner: Car A has a head start and is a distance $d_A$ beyond the starting line at $t=0$. The starting line is at ...
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votes
1answer
84 views
spacetime or only space? [closed]
I was thinking one day, if time doesn't exist and there is only space. I was trying to think about what other measurementunit could be instead of speed(m/s) and acceleration(m/s2) and I came to ...
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votes
0answers
152 views
Does time actually exist or is there just a single stateful system being updated over time? [closed]
What I mean is, is there a past, future and present? or just a NOW which changes?
I'm a computer programmer so the second alternative is from my programming experience. In this second alternative, I ...
0
votes
0answers
61 views
time slowing further into the earths atmosphere [closed]
According to Steven Hawking in his book "A Brief History of Time" time moves slower the further it is into the Earth's atmosphere. This is because a light wave loses energy the further it goes into ...
0
votes
2answers
61 views
What is the common difference between partial time derivative and ordinary time derivative? [duplicate]
What is difference between partial and ordinary time derivative?
for example: what is difference between $\frac {\partial v}{\partial t}$ and $\frac {dv}{dt}$?
where the $v$ is velocity.
-1
votes
1answer
76 views
US time zones and Daylight saving time, energy efficient? [closed]
As a foreigner, United States has a very complex time system for me. Central Time Zone, North American Eastern Time Zone, ...
-1
votes
1answer
313 views
-1
votes
2answers
114 views
Can time dilation be explained by limitations on computing power?
Are there any ideas of explaining the time dilatation as limits in "computing power"? What I mean is basically that the greater is a concentrated mass, the harder is to "compute" what happens in such ...
-1
votes
1answer
148 views
Calculate time to go from one point to another point [closed]
in a 2D football game I want to calculate cycle(time) until ball go from one point
to another point.
in this link exist all fomulas that we need for my problem but anyone does not have any parameter ...
-1
votes
1answer
67 views
Does the movement of things in the universe will cease one day?
To start or change the movement, we need a force. This force, according to Newton's second law, is variation of quantity of motion from the object per unit of time.Therefore, if the variation does not ...
-1
votes
2answers
178 views
length, width, and time
is it possible to have length, width and time. A 2D or 1D object with the 4th dimension (although then there would not be 4 dimensions so would it b 3D?) .
-1
votes
1answer
102 views
How do photons experience time? [duplicate]
I know that as velocity approaches the speed of light the time dilation shoots to infinity as shown below.
1)So I want to know how time is perceived from the point of view of the photon?
2)Since ...
-1
votes
3answers
180 views
Why are precise frequency standards important in the telecommunications industry? [closed]
I understand why having a precise definition of time can be very useful for navigation purposes. The GPS system works using the simple equation $d=ct$, where $c$ is the speed of light, so the ...
-1
votes
1answer
97 views
Existence of time in some other universe [closed]
Is it necessary that time should exist in another universe if it (universe) is there? How do we perceive timelessness?
-2
votes
11answers
494 views
Are there any theories that explain the very beginning of absolutely everything? [closed]
Of course there's the theory of The Big Bang, and there are theories on what caused The Big Bang, but what was the cause of the very first thing that ever happened? What started every
I also won't ...
-2
votes
5answers
1k views
2 balls falling hit the ground at the same time
There are 2 balls in a vacuum, next to each other but not touch. They are on the edge of a surface they will both leave the table at exactly the same time. One gets pushed harder than the other. The ...
-2
votes
3answers
408 views
How does Time traveling work in practice?
There are multiple theories about time traveling. One is "proven": The time slows down according to your speed. The satellites in space are traveling faster than us, thus their clocks slows down a ...
-3
votes
4answers
190 views
How can we be sure about the constancy of atomic clocks as in the Hafele and Keating time dilation test?
Atomic clocks were used in Hafele and Keatings experiment which supposedly helped to prove time dilation.
Time Dilation Proof - Hafele and Keating
How can we be sure other forces didn't act upon the ...
-3
votes
2answers
115 views
Is this a great flaw in big bang theory? [duplicate]
Einstein said that, Time & Space cannot exists without one another. Big bang says, time didn't exist before the big bang. So the Primordial ball referred in the Big Bang theory didn't had any ...
-3
votes
1answer
27 views
How to find time taken for a spinning top to stop? [closed]
The angular position of a spinning top is given by $\theta = t^3 - 72t$, where $t$ is in seconds
and $\theta$ in "radian".
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votes
4answers
731 views
Relativity in Real Life
I have no formal training at all in relativity. But I was just wondering if our perception of time is altered by different events. Here are some examples I had in mind:
If I touch a stove for 10 ...
-4
votes
1answer
154 views
What is the difference between UT0, UT1 and GMT time?
Every reference I find says that they are "essentially" the same, which we all know really means that they are not the same, but different only by a some small amount that someone else other than me ...
-4
votes
1answer
146 views
If an apple that is rotten transports back in time will it become fresh again? [closed]
I was wondering about organics that traveling back in time. for example. I'm standing on main street where there is a an apple tree about 30 years old. I pick a rotten apple from it, I go back in time ...
-5
votes
3answers
565 views
How accurate is the time on a digital clock versus the time on internet clocks?
How accurate is the time on a digital clock versus the time on internet clocks? The internet clocks seem slower than internet clocks. So which is the correct time? What are the most accurate clocks?
