# Questions tagged [time]

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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### Time a fundamental force? [closed]

If time is emergent especially immediately after big bang then is it a fundamental force that appeared at that moment
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### If time is an illusion, then is free will also an illusion under such illusion? [closed]

Space time has existed from the beginning of the universe and until its end and humans exist on 3D plane. Due to its limitations, it is only able to experience one period of spacetime, like being ...
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### Laws of nature and relative motion [closed]

According to the principle of relativity, the laws of nature should be independent of the relative movement of different frames. My doubt is the meaning of "laws of nature". So, suppose a ...
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### A 'better' definition of time [closed]

I have been annoyed by official definitions of time from many Google searches and decided after listening to Sean Carroll's podcast to write my own. Here is what I did so far: What is time? A state ...
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### Welche physikalische Wechselwirkung hat die Zeit in der Natur? Bei Temperaturen unter 0 Grad Celsius wird Wasser zu Eis [closed]

Welche physikalische Wechselwirkung hat die Zeit in der Natur? Bei Temperaturen unter 0 Grad Celsius wird Wasser zu Eis. What physical interaction does time have in nature? At temperatures below 0 ...
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### Force from time and velocity

Let's say I have a goal velocity $(v)$. In $n$ amount of time $(t)$ (let's say two seconds). What is the formula for finding the amount of force I would need (not counting other forces like drag/...
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### Can Toroidal High Voltage Capacitors Cause Time Dilation?

I read in NASA's Warp Mechanics, they managed to warp space time with a high voltage toroidal capacitor, as detected by an interferometer. So I was wondering, is it possible to dilate time with this ...
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### Are zero meters equal to zero seconds? [closed]

Is $0\,\mathrm m=0\,\mathrm s=0\,\mathrm g$? This would seem somewhat logical given the mathematical properties of physical units, but also not necessary.
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### Three Questions On Special Relativity [duplicate]

Twins Paradox Using the simplified version of the paradox, where acceleration to near light speed and the turning of the spaceship are almost instantaneous, the paradox is completely symmetrical - in ...
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### How the information is related to time in physics?

The interpretation of information in physics is confined to assuming instant interactions and stationary states. Today we started to learn that when having higher resolution measurements, even most ...
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### Time dilation in the center of the earth [duplicate]

The time dilation seem to slow time in stronger gravitational fields. Lets say we put a person with a clock in the center of the earth. It will feel no gravity since it's pulling from every direction ...
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### How is atomic time defined in Hartree units?

As in Planck units, I believe Hartree units have a fundament unit of time, Atomic Time, something like $2.4188843265857(47)×10^{−17}$ s. My question is what exactly is it that happens in this time? ...
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### Two ships meeting in the distorted spacetime of a Krasnikov tube - what happens?

Given a Krasnikov Tube: a speculative mechanism for space travel involving the warping of spacetime into permanent superluminal tunnels. The resulting structure is analogous to a wormhole or an ...
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### Does "absolute time" exist, in any sense? [duplicate]

When physicist Steven Weinberg (who, sadly, just died recently) wrote a book about "The First Three Minutes" of the universe, doesn't this imply that there really was a distinct period of ...
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### Is time taken by light to travel any distance 0 or finite? [duplicate]

According to relativity, Light does not experience any time. So it must travel any distance in no time. But, we know that light has finite speed $c$. So it should take finite time.
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### Clock in gravitational field

Weinberg writes in his book: Consider a clock in an arbitrary gravitational field, moving with arbitrary velocity, not necessarily in free fall. The equivalence principle tells us that its rate is ...
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### Condition for a time-dependent transformation to be a canonical transformation [duplicate]

I'm looking for a sufficient condition to determine if a given transformation is a canonical transformation. I have found two conditions, but they are only valid for the case that the transformation ...
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### Two bodies A and B fell from rest Compare the time of arrival of objects A and B to Earth [closed]

Two bodies A and B fell from rest from a height of 100 m, and body A reached the ground Directly while body B hits an inclined surface making its velocity horizontal as shown in the figure, Compare ...
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### How to find time at any point on the path of a projectile motion?

I know how to find the time of flight and all but what if I chose a random point on the path of the projectile (no air resistance) and ask the time at which the particle is present there, then how can ...
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### How can we perceive light if light doesn't move through time? [duplicate]

From my understanding in space-time everything moves at the speed of light $c$ in some direction of this four dimensional space. Light itself moves only through space, so it doesn't move at all in ...
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### Should time be a loop or a line?

It's interesting to see that torus was so popular in physics, that it worked so well. There was famous Gauss–Bonnet theorem which stated basically $$\oint_S K dS= 2\pi \chi(S)$$ where K was the ...
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### Imaginary Hamiltonian

The Hamiltonian for nuclear spin independent parity violation in atoms is given by: $$H_{PV} = Q_w\frac{G_F}{\sqrt{8}}\gamma_5\rho(r)$$ Here $Q_w$ is the weak charge of the nucleus (which is a scalar),...
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### Why is absolute time considered an axiom of Newtonian mechanics? What statements are based on this axiom?

I guess absolute time is associated to classical mechanics because people like Newton believed in that concept, but are there actually any statements whose derivation is based on this assumption? I've ...