Dilation Definition and 1000 Threads

Before posting reply, please think about time as a concept that is used to describe a change relative to some other change. For example, a traveler will arrive on a destination after Earth completes x rotations. At the beginning, people used Earth rotation as a reference change and called it a...

Timedilation seems clear when you study special relativity and read about the Hafele-Keating experiment. Gravitational redshift seems logical when you assume that light should lose energy when it is leaving a gravitational field. But the two seem to be contradictory to each other. Question 1...

Suppose there is person A in a frame S with respect to which a light beam clock is at rest , now time taken by a photon to go from bottom to top is L/c according to A. now the same clock is looked at by a person B traveling with velocity v w.r.t S and according to him time taken by photon to...

One of the basic foundation of special relativity is that the speed of light is a constant, hence time is relative to the inertial framework reference. Usually GPS is also mentioned as a modern experimental evidence. My questions: if Maxwell's equations describe EM fields, how can we derive a...

I meant to say fast moving "objects" in the title, my bad... my title kind of sucks https://en.wikipedia.org/wiki/Relativistic_electromagnetism#The_field_of_a_moving_point_charge That section is basically what my questions are about. I want to know generally about the overall forces. Two...

So I just finished reading my textbook on special relativity and am a bit confused by the discussion of time dilation. We equip an observer with a light source, a mirror, and a clock and herd him onto a train moving at constant velocity relative to a second observer located at the station. If...

I was wondering if time on a planet which is exactly twice the mass of the Earth would pass exactly twice as slow relative to Earth time? So after a year on this big earth, two years would have passed on earth? Thanks

When I started to learn about GR, I have been thinking, that there is simple relation to gravity and time dilation, that higher gravity means bigger time dilation. But later thanks to PF discussions I learned time dilation is related to gravitational potential and not directly to gravity. But I...

Hi Folks-I am interested in knowing whether, in actual practice, people on Earth would see their 99% of c colleagues moving around in fast forward motion and if the reverse would be true from the vantage point of the relativistic astronauts who are moving away from earth. I suspect that since...

The rate that a stationary clock slows down near a massive object, relative to one far away, can be read off from the Schwartzschild metric: $$c^2d\tau^2=\left(1-\frac{r_s}{r}\right)c^2dt^2-\left(1-\frac{r_s}{r}\right)^{-1}dr^2-r^2\left(d\theta^2+\sin^2\theta d\phi^2\right)$$ by setting...

Hi Everyone, first I want to say I have no formal education or background on these topics, but find them very interesting and research and learn as much as I can on my own. With that in mind, I am hoping some of you will have the patience to explain what I don't seem to understand. What I am...

If a frame is moving at constant velocity relative to an observer, this observer perceives a time dilation and a length contraction. But in this case how the velocity (length/time) can appear constant ? It is expected to be contracted.. Thank you in advance for the explanation

I thinking how to calculate time dilation in different time with usage of average mean density. Lets set that Universe have average mean density ##\Omega_{t1}## at time t1 and ##\Omega_{t2}## at time t2. How to get time dilation, for comoving observers, between time t1 and t2?

Is time dilation an actual phenomenon or it is just an apparent change relative to some other frame of reference? If it is so then why the age of a person slows down and elongates actually?

Hello. I need some help understanding time dilation. So the idea is that moving clocks tick slowly. Say there was an observer A who, by his frame of reference, is stationary, and he sees an object B moving past it at high velocity. From what I understand, to A it would appear as if B's clocks...

When we talk about the BB occurring 13.8Billion years ago (see time chart below) http://en.wikipedia.org/wiki/Big_Bang#/media/File:History_of_the_Universe.svg Does a 1ns of interval time at each of those points in time mean the same thing as a 1ns interval of time now, or is the measurement of...

Sorry for the lame question, but I was wondering if someone could help answer the following. I have two synchronised clocks which I place on two different space ships which then accelerate away from me at the same rate and time until they reach a given speed. Ship A then slows down to be at...

I was talking to my dad not long ago and he asked me an extremely valid question, so basically, the question is. If I'm next to a supermassive black hole, and 1 hour for me is 77 hours on earth, and my dad rings me, bearing in mind you would an extremely good signal, but let's just say i...

According to Wikipedia, the gravitational time dilation formula is given by t_0 = t_f \sqrt{1 - \frac{2GM}{rc^2}} = t_f \sqrt{1 - \frac{r_0}{r}} where t0 is the proper time between events A and B for a slow-ticking observer within the gravitational field, tf is the coordinate time between...

As per theory of special relativity the time in moving frame R' is supposed to run slowly compared to the stationary frame R. But isn't the stationary frame R moving wrt frame R' in the opposite direction. For an observer in stationary frame R', R would be moving with the same velocity wrt to it...

A person on Earth signals with a laser beam at 6 minute intervals. Another person on a rocket moving away from Earth at 0.600c detects the signals. At what time intervals does the person on the rocket receive the signals from the Earth. The formula we use is: Δt=Δto/sqrt((1-u2/c2)) u = 0.600c...

Hi all, First post here. I have been debating with a colleague today about time dialation. I am certain that an astornaut in space will experience more time or age faster than people on Earth due to time dilation of a massive object. He is saying that he will come back younger. Whos right...

Is time dilation a factor in the calculation of the expansion speed of the universe?

One way to regulate blood pressure is through vasoconstriction which in turn increases peripheral resistance, but also decrease the amount of blood that passes through the vessel. These two changes have opposite effects on blood pressure. So is it because the resistance increase effect lead to a...

Hello PF, A question on special relativity I've not found an answer to,I tried to google it but no luck, so here is it : If you were to observe a moving body whose speed is very near to the speed of light, will you see it slowly due to time dilation, or you'll observe it as it really is, very...

Let me begin with the fact I am a rube in the field of Quantum Physics. I seem to have an innate grasp of certain concepts but if it comes to proving theory with math, I’m out. That being said, I am completely fascinating with Miguel Alcubierre’s theory on collapsing, or “warping”, space...

I'm currently reading https://www.amazon.com/dp/0199236224/?tag=pfamazon01-20. The book claims that, according to the equivalence principle, acceleration and gravity have the same effects. So if gravity slows down time, shouldn't acceleration also slow down time? The book seems to state this as...

In case when we have accelerating spaceship without any influence of gravity, what is causing the time dilation? Is it primary caused by the speed of the spaceship or it is caused by acceleration leading to higher speed? What is the primary cause of time dilation?

Would the universe end if you entered a black hole? What I mean by this is that due to time dilation would time elapse so fast for the universe outside the black hole relative to you inside it that all the stars would burn out and all that wouild be left would be other black holes?

Does time go slower on the hemisphere of Earth that is currently rotating counter to Earth's orbit than the side the side that is rotating with Earth's orbit

Hi. If calculations of the Lorentz factor are by thought experiments using the constancy of the speed of light in inertial frames (I also know of using simultaneous equations for a light signal in two different frames with a conjectured Lorentz factor to calculate it but this also involves...

I was looking at Time Dialation a bit today and some of the experiments with it. Considering time goes approximately 1/3 as fast as normal, under 100% the speed of light, what would happen if you went past the speed of light with a craft capable of warping. Would it have no effect due to the...

According To Einstein's Relativity. Supposing a Man Went To Another Planet That Has a Gravity More Than Earth Hundreds Of Time Which Means That Time Is Too Slower There Than Earth. If We Say That 1 Hour In That Planet Is 10 Years On Earth And He Stayed 2 Hours There Will He Comeback To Earth...

Homework Statement A muon has a lifetime of 2.20 x 106 s when at rest, after which time it decays into other particles. A) Ignore any effects of relativity discussed in this section. If the muon was moving at 0.99 c, how far would it travel before decaying into other particles, according to...

Hello. If time is infinitely dilated at the edge of the EH, how do we observe accretion?

I'm trying to show that \int d^3x \,x^\mu \left(\partial_\mu \partial_0-g_{\mu 0} \partial^2 \right)\phi^2(x)=0 . This term represents an addition to a component of the energy-momentum tensor \theta_{\mu 0} of a scalar field and I want to show that this does not change the dilation operator...

Im looking for some easy equotation which would help me to make graph of time dilation depending on gravity expressed not in relation to Schwarzschild radius but simply and directly to gravitational acceleration. I would like to get some easy graph similar to this...

This is something I've been meaning to write for a while, I finally got the time to do it, though the topic isn't currently "hot". I'm sure it will pop up again, though. Imagine we have two observers, moving at a constant velocity relative to each other far away from any objects that might...

How close do you have to be from a black hole to experience noticeable time dilation. I always believed you will not experience noticeable dilation until you are at or in the event horizon is this correct? Also does rotation/spin of mass such as a planet decrease it's inherent gravitational...

Hi everybody, I'm learning Special Relativity, and probably ok with four vectors, the metric equation, the Lorentz Transform, and the Doppler shift, etc., but enough about me. I'm still a little confused about time dilation. In several hypothetical examples of SR that I have seen, two...

When a spaceship accelerates to 1.000 kmh, the effect of time dilation is tiny. But what happens if this spaceship accelerates in an inertial frame whose total speed is much slower or whose time goes much faster, will the time dilation effect be the same? If the spaceship travels in a inertial...

I have been asked about time dilation which I thought I understood, but maybe you can help me provide an answer? If a spaceship is traveling at 0.866c then time will slow by a factor of 2 due to the speed the spaceship has. Why? If it is alone in space, light years away from any other body...

I'm under the impression that one sees clocks slow down when watching distant objects approaching strong sources of gravity, such black holes. And that objects in an elliptical orbit travel faster when they are near their attractor. I can't quite figure out how these two phenomenon work...

Assume you have a 2 particles sitting inside a double potential well. Each particle occupies one side of the well and given enough time the particles may both be found on the same side or swap sides (tunnelling). Assume that the well is inside a gravitational field. It is positioned in such a...

Hi all,as I understand it, GPS satellites are offset prior to launch in order to correct for the time dilation that they experience in orbit. I am very confused about how this works in practice. I think the velocity of a GPS satellite wrt a position on Earth would depend on the position on Earth...

If an observer was traveling with a Lorentz factor that would make that observers time slower than someone's on Earth, what would that observer see watching a live video feed, or if it was possible to observe Earth with a telescope, and vice versa? I understand that either party would only see...

IIUC, there are two different interpretations of GR - either as curvature of space time (as in Misner Thorne Wheeler) or as a (spin-2)field that influences all matter (as in the books by Weinberg or in the Feynman Lectures on Gravitation) and that leads to the underlying Minkowski metric being...

Hello! I have some confusions about this topic, I'm a physics newbie so my question may have no sense, please have mercy ;). It's supossed that relativity only considers observation as valid "what we see", but observation it's independant of what we know (we can't tell how distant we are from...

Homework Statement The new earth-Pluto SuperShuttle line boast that it can take you between the two planets (which are about 5.0 h apart in distance) in 2.5 h according to your watch on board the shuttle. Assume that the shuttle travels at a constant velocity. a.) What time interval must the...

If we use one gravitational field in GR and try to desribe it, we will see that from the perspective of the observer on the centre of mass of the object the clock on the hovering observer (farther away from the gravitational field) runs faster, while from the hovering observer's perspective the...