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My question is, do other types of mathematics, say a cellular automata as an example, have the intrinsic time direction that the equations lack? With a CA, all steps have to be completed sequentially. A reversible system is not related to whether it is differential equation, algorithm or cellular automata. It is the underlying model, or physics, ...

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I'll concentrate on cellular automata in this answer, because it's a good example, and should help to give a good intuition about algorithms in general. The answer is: most cellular automata do have an intrinsic time direction, but some don't. The most famous example of a cellular automaton is John Conway's Game of Life. This is an irreversible cellular ...

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Not only the position in the gravitational field is important, but also the velocity. Consider the Schwarzschild metric $$\text{d}\tau^2 = \left(1 - \frac{2GM}{rc^2}\right)\text{d}t^2 - \frac{1}{c^2}\left(1 - \frac{2GM}{rc^2}\right)^{-1}\left(\text{d}x^2 + \text{d}y^2 +\text{d}z^2\right),$$ where $\text{d}\tau$ is the time measured by a moving clock at ...

0

Clocks tick slower at lower altitudes. So 1. On the surface of the Earth will be the slowest. Now since the ISS has no way of knowing whether it is in orbit or in deep space, you might think that clock 2 and 3 should tick at the same rate. But instead clocks 2 and 3 will just feel like as if they were ticking at the same rate. Astronauts at 2 and 3 will not ...

1

There is a standard way to find out if the spacetime around you is curved. Surround yourself with a sphere of small test masses and wait and see what happens. If the sphere stays exactly the same shape you're in flat spacetime but if it changes shape or volume you're in a curved spacetime. In the case of the ISS the test masses nearer the Earth than you ...

0

Since this old question got bumped I might as well add my own answer. In classical mechanics, two masses that interact gravitationally define a two-body problem, which follows Kepler's laws: they will orbit each other in an ellipse, and Kepler's Third Law states that $$n^2a^3 =\mu,$$ where $a$ is the semi-major axis, $\mu=G(M+m)$ and $n=2\pi/T$, with $T$ ...

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I am 100% confused by this. I do not understand why the plane clock runs slower than the earths clock? Why the preference on the plane? Why not on Earth? Why does the plane lose time, and not the other way around? (I cant think why one body or the other gets the preference as from the perspective of one or the other they are both moving the same). From the ...

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If you define "now" to be all those points in space and time that have hypothetical, pre-synchronized, stationary clocks that read the same time as your clock, then there "currently" exists a hypothetical observer somewhere, who is moving relative to us, for whom "now" includes Earth, circa 1900. But these notions of "now" are different for the two ...

1

The first statement is very much true. Light moves a finite, if very fast, speed. Even ignoring any movement/ relativistic effects this simply means that observers closer to earth will see it in it's most recent state. It may sound strange for light, but we see exactly the same phenomenon in sound, an observer noticeably closer to the source of a sound will ...

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No. Not that we know of unless we change the current laws of physics to allow faster than light travel or imaginary mass

2

I'm not entirely sure I understand what you're asking but here is how I've interpreted your question: It seems like all of the laws of physics are reversible in time. That is, given the state of a physical system, it's possible to both go forward in time or backwards in time from that state. Assuming this is the case for physical laws and the equations ...

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these papers are predicting the possibility of measuring a particle or electromagnetic waves to move faster than light without violation of Lorentz transformation or causality. According to the papers It could solve many paradoxes related to special relativity, Twin paradox, Ehrenfest paradox, Ladder paradox and Bell's spaceship paradox. in the papers it is ...

0

From this data, you don't actually know how the speed varies between steps. If you have more information about the acceleration then you could change the model from this but I would propose the following... Assume a linear change in the speed between steps, you could take a simple graphical approach. Plot the speed (in km/s) on a vertical axis, against the ...

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Well, this is an easy problem in kinematics. "The rule" for solving it is drawing a graphic of the (differences of) time versus the speed. You will get some points. Join these points to obtain a trapezoid histogram. So, what do you think it is the area beneath this curve? It has the dimensions of a length, so... Now, you want an average speed, that is a ...

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the astronaut [...] relative to us, is motionless in space, observing us I think what you mean is that the astronaut is in the same frame-of-reference as the centre of the 'super cluster'. If the astronaut was motionless relative to us then she/he would experience/measure the same flow of time as us. You should note that the commonality between Galilean ...

4

If you say that earth's velocity around the sun is 67,000 mi/h, your reference point is the sun itself, which makes the aeroplane's velocity 68,000 mi/h, not 1000. Using special relativity only, and (A) observing from the sun, a clock on the plane would seem to run slower than a clock on earth. A person (B) on earth would measure also measure an ...

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The aeroplane is moving in the atmosphere of the earth, and so how can you say that the earth is moving faster, when viewed from outerspace. I think the aeroplane will still be faster.

1

Basically, the universe has a speed limit. No object can ever exceed the speed of light. Now imagine you decide to prove Einstein wrong by building a train capable of nearly reaching the speed of light, and then shooting a bullet forward in that train, so that the bullet will break the speed of light. In order to preserve this speed limit, time for you and ...

2

Basically what your asking is if information can be transmitted faster than the speed of light. According to quantum mechanics, it is impossible to use quantum entanglement for transmitting data faster than light. This is know as Eberhard's theorem, more details about can be found here (i'll try to provide a link with full access to the article). ...

3

Muons are single-particle excitations (states) of the $e-\mu-\tau$ quantum field, except that these states don't have definite values of energy (they are in a superposition of states that have definite energy). Because states with different energies change at different rates, this superposition changes with time. After some time has elapsed, the ...

-1

If a star Is 13.82 billion light years away It takes 13.82 billion years for us to see the Image so 13.82 billion + 13.82 billion = 27.64 billion years old because while that Image was flying through space, time was still moving forward also If I set up a camcorder telescope 1 light year away and look at earth then I can see the past on earth the closest ...

0

It depends what you mean by 'cannot happen'. Go back to a period before you saw that documentary, but not so far back time didn't exist, in ancient Greece there began a raging debate between Plato and his student Aristotle, about the nature of knowledge. Ultimately Aristotle's views gave us theories such as causation, and centred around observed ...

0

The simple answer to your question is that if there are other universes by virtue of the expansion we see in the universe around us, there is no way we can know anything about them directly (since the distance between them is increasing, and light can only go at light speed, so no information exchange). Now, with that said, Velenkin thought about Alan ...

1

A clock near the surface of the earth will run slower than one on the top of the mountain. Rather: the geometric (and kinematic) relations between two (or more) given, distinct, separated clocks must be determined and taken into consideration in order to compare intervals (from any one indication to any other indication) of each clock to each other, on ...

4

Yes. More specifically, if $d$ is the distance between the planets in their rest frame, then in the astronaut's frame the distance between the planets will be $\frac{d}{\gamma}$ so the travel time as measured from his frame will be \begin{align} t_\mathrm{astro} = \frac{d/\gamma}{v} = \frac{1}{\gamma}\frac{d}{v} \end{align} Notice that the quantity $d/v$ ...

2

Yes, you'll gain extra hours, but you'll lose them on the way back, unless you keep going round. Let's assume you're in a plane flying along the equator, moving at 800 km/h (in the direction of the earth's travel) - a normal jetplane speed. The earth is rotating so that a point stationary on the equator moves at 1600 km/h. That means that, for every km you ...

2

What if without meeting they send a light pulse to each other, such that they can know each other's age The result will still be the same - each twin judges the other twin to be ageing more slowly than themselves. However, sending a light pulse to each other involves other factors that must be taken into account such as time of flight and ...

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If the twins never meet, but just continue travelling in a straight line at constant velocity then each twin will see the other as being younger. The *paradox*$^1$ only occurs if one or both of the twins is accelerated, which of course is necessary for the twins to meet again. $^1$ it's not a paradox of course, just an unintuitive result!

1

Think about this In your brain there is a clock too. In other words, everything has a clock in itself. The clock in this meaning is the electron and molecule activity. Both gear and battery is electron and molecule activity. And inside your brain is another kind of electron and molecule activity Time dilation is about the reality that all electron and ...

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Time dilation (and also length contraction) always occurs with respect to an observer in a different frame of reference. You, in your own inertial frame, will not notice any difference. However, when you compare your measurement to that of an external observer, you will see a discrepancy in the results. If you enter a spaceship and go on a journey through ...

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