# Tag Info

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There are a few problems with this question, but also the potential to answer some parts. The short answer is that reduced gravity (in relation to an observer who is far removed, as you mentioned frequently) will allow time to appear to pass more quickly (once again, relative to us, as the other answer said.) This would not mean that time would be observed ...

0

"Local" time is invariant. It does not respond to gravity, or speed, or anything else. All you can ever experience is Time. You can't travel faster than light or time. An object sitting on top of Mt. Everest will experience time as being unchanged, but us folk at sea level will perceive it as ticking very slightly faster. So there is no such thing as "our ...

-1

time will disappear in the same way it appears I don't know how to explain it but in easy way the the end is just the beginning and it will look like a cycle as it began it will end

1

I'm not sure what might be confusing you. Assume, as in most cases with the Golden rule, that the transition rate is constant, $\Gamma$. So, for small times, the cumulative transition probability is $W=\Gamma t$. Think of the transition as leakage from a vessel. At $t=0$, no water has been lost, but with a constant rate of leakage, $\Gamma$, the longer ...

0

I think we can divide most potential solutions into 3 broad categories depending on what sort of reference is used: Some property inherent to your body or brain: As mentioned in rob's answer, the most obvious is probably to use one of several second counting methods, or a song, drum beat or similar that you have experience performing at a fixed pace. Some ...

1

If your hypothetical stranded astronaut is able to use her own head-to-sole height as a length reference, I would expect her to count seconds by muttering "mississippi one, mississippi two, mississippi three" the way she has been doing since playground days. If your astronaut is a musician she might recall a piece of music for which she knows the ...

1

You've stated that you'd recreate an SI length unit $\text{m}$ (meter) from knowledge of your own height. So you've got a reasonably accurate ruler. Create a small angle pendulum with length $L$. Use this clock to measure the speed of light (in vacuum). Call this $c_p$ (measured with the planet's pendulum period). The ratio of $c$ (measured in SI units ...

1

One doesn't need to go to GR; SR is enough for the argument. Eternalism (the block theory of time) states that the past, present and future exist. This should be contrasted with Presentism which states that only the present exists. To see what this means, consider as is normal in physics, time as a dimension in analogy to space; but whereas we have the ...

0

Photons are emitted and absorbed. Between emission and absorption there is no proper time because the spacetime interval of lightlike movements is zero. Light is generated by the absorption process, not by the travel of light. So there is no reason to fear that it should be dark.

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You've mixed up which time dilates for which observer, and written yourself into a paradoxical corner: if going closer to the speed of light slows time for the object going that speed, and if time slowing down means going slower, then the conclusion is that "the faster you go, the slower you go." Which obviously doesn't make sense as you've pointed out. ...

-2

If a photon carried a wristwatch, it would not tick. But us subluminals still see the photon move because for us, time has not stopped.

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Time being a measurable quantity according to the beat of cesium atomic clock, it cannot be stopped. If the light ray hitting your eye is taken as a measure of time. Then you can absolutely stop the time by travelling at the speed of light.

0

Based on the rewording well-given by @WhatRoughBeast we can consider two events: the astronaut passes by Earth at $t_1 = t_1' = 0$ and $x_1=x_1'=0$, where the unprimed frame is at rest w.r.t. Earth, and the primed frame is at rest w.r.t. the astronaut. the astronaut arrives at the planet: $t_2=D/\beta$ and $x_2=D$ where $D$ is measured in light-time units ...

1

But then I'm assuming the time it takes him for an observer is equal to 16 years, am I correct in doing this? I think not since that means the astronomer would be travelling at the speed of light to an observer... Okay, first thing: an astronaut (Greek, star sailor) is different from an astronomer (Greek, star namer). The former is seen at the wheel of ...

4

You got it half right, but you got so focused on the correction factor that you forgot to calculate the trip time in your rest frame. In deference to Bill N, let me rephrase the question, hopefully more to his liking. The astronaut is travelling to a star sixteen light years away which is stationary with respect to earth. During this trip he ages fifteen ...

0

No, you're not misreading the question. From reference frame here on Earth, light would take 16 years to reach the start 16 light years away. However, this problem takes a look at special relativity. As the astronaut travels at relativistic speed, he experiences time dilation. That means that clocks back on Earth will appear to tick fast as opposed to ...

2

Is there a place in the universe where time doesn't exist? and question: Don't know if it's valid though. What could be a strong proof for the same? Please note that "proof" applies to mathematical formulae, not to physics. Physics confirms or falsifies a statement predicted by a mathematical formula. To confirm , one has to measure and ...

0

I will use this reference Chapter 3 Time dilation from the classical wave equation from Understanding Relativistic Quantum Field Theory by Hans de Vries 3.1 Signal propagation: The bouncing photon clock The classical wave equation tells us that the propagation is on the light cone, and the propagation speed is c. With this as a starting point we will show ...

-5

On the wikipedia page for time travel, it mentions that Robert Forward said Yes, here it is: "Physicist Robert Forward noted that a naïve application of general relativity to quantum mechanics suggests another way to build a time machine. A heavy atomic nucleus in a strong magnetic field would elongate into a cylinder, whose density and "spin" are ...

3

While there are probably a lot more problems with that statements, here are a few : A Tipler cylinder is infinitely long, hence it would require the nucleus to stretch infinitely far (and due to limitations on the speed of light, for eternity) before actually qualifying as one. I am not quite sure a nucleus would even survive such a stretching. It is a ...

1

A pendulum in a gravitational field experiences an instantaneous torque about its pivot point of $$\vec{\Gamma} = \vec{r}\times m\vec{g}$$ where $\vec{g}$ is the instantaneous gravitational field, and $r$ is the distance from the pivot point to the CoM. For purposes of this answer $$\vec{g}=-G\frac{ M_E}{(R_E + h)^2}\hat{k}$$ where $m$ is the pendulum ...

0

Let's say your goal was to watch your twin die. Assume you take care of your self (look after your health and safety) but want to really live longer. There are other options. One is rockets. Get big rockets, take off and get up to a high speed, at some point turn around and fire your rockets to come back. You will have aged less. To age half as much you ...

1

Put the car on a treadmill. Put walls around the treadmill with images of trees and clouds, to create an outdoorsy impression, and printed on a loop of flexible fabric. Connect the fabric loops to the treadmill so the images move at the same rate as its upper surface. Put wheels on the underside of the treadmill, geared so their axles move forward at twice ...

2

The reason these statements are consistent becomes clear if we quote from the Landau & Rumer book a little more extensively: Ahead of us is a very long railway line with Einstein's train moving along it. At a distance of 864,000,000 kilometers from each other there are two stations. At its speed of 240,000 kilometers per second, Einstein's ...

0

Have a look at the answers to Is there a proof of existence of time? to get some idea of how time works in relativity. In particular you have to distinguish between the time coordinate and the flow of time. In relativity the flow of time doesn't exist. When we talk about the flow of time we normally mean the changes measured by some mechanism (i.e. a clock) ...

0

Wouldn't it take an infinite amount of time to move across an infinite number of points" This is incorrect. The correct statement closest to yours is it takes an infinite amount of time to move across an infinite distance". Infinite number of points does not necessarily mean infinite distance. In fact, to see whether a distance is infinite or not, you ...

-2

There are many theories that postulate "aether" and to be honest, I never really thought about it, mostly, because that is what was thought to me in school and physics study. Since I'm 14, I tried to understand general relativity. I understood the formulas, but never the underling reason, it simply did not make sense to me. Einstein solved this riddle for ...

1

If you stick to the newtonian model of universe, the yes, clocks do measure time. But to "measure" time, you must first define the least unit of change to act as a reference model. We call this a "second". There are different ways to measure a second, but anyway, in newtonian models of universe, a second always stays a second. If you delve into einsteinian ...

3

In a sense to be discussed below, clocks do indeed measure time, and this is a very definite experimental result that gives us an experimental definition of time. We experimentally observe that the ratio of the rates of the same two physical processes taking place in an inertial laboratory is always the same. A clock pendulum swings a set number of times, ...

0

Clocks measure themselves. If you were to move forward or backward in time,the clock will not update itself,like a thermometer or GPS will.

2

"would the time dilation for the ship that travels in a straight line be the same as that moving in a circle?" The short answer, with a few more assumptions, is yes, or it certainly can be. Firstly, we need to agree to leave aside the problem that one cannot relativistically orbit the Earth, at least not in a freefall orbit. The orbital speed for a ...

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