What is Gravitational time dilation: Definition + 113 Threads
Gravitational time dilation is a form of time dilation, an actual difference of elapsed time between two events as measured by observers situated at varying distances from a gravitating mass. The lower the gravitational potential (the closer the clock is to the source of gravitation), the slower time passes, speeding up as the gravitational potential increases (the clock getting away from the source of gravitation). Albert Einstein originally predicted this effect in his theory of relativity and it has since been confirmed by tests of general relativity.This has been demonstrated by noting that atomic clocks at differing altitudes (and thus different gravitational potential) will eventually show different times. The effects detected in such Earth-bound experiments are extremely small, with differences being measured in nanoseconds. Relative to Earth's age in billions of years, Earth's core is effectively 2.5 years younger than its surface. Demonstrating larger effects would require greater distances from the Earth or a larger gravitational source.
Gravitational time dilation was first described by Albert Einstein in 1907 as a consequence of special relativity in accelerated frames of reference. In general relativity, it is considered to be a difference in the passage of proper time at different positions as described by a metric tensor of space-time. The existence of gravitational time dilation was first confirmed directly by the Pound–Rebka experiment in 1959, and later refined by Gravity Probe A and other experiments.
Consider a sphere with outer radius r2 and a centred inner cavity of radius r1, forming a constant density shell with density p.
Let's say the time dilation on a clock on the inner surface of the shell is ta.
Now the shell with filled with a material of the same constant density as the shell...
Here is another question
As far as I know, gravity slows time...So it would be true that a person who lives in for example the moon would live less than a person who lives on earth?
Or a person who lives on 25th floor lives longer than a person who lives in basement? Of course the difference...
Hi!
I am really bad at physics so bear with me...
I saw some very interesting 3 hour physics-marathon on TV the other day.
I have never gotten an actual clue on how things work relativisticly even though I've read a book by Brian Greene some years ago.
Since then I have tried to...
First, thanks for all the replies to the first post. I was able to predict this result (an engineer did the proof) using an analogy for gravitation I worked out to replace the standard marble rolling on a rubber sheet analogy used to show the effect of curved space time, which is useless on a...
The time dilation caused by gravity on the surface of a planet is equal to the time dilation for an object moving at the planet's escape velocity in space. This can be proved using the Schwarzschild metric. GR doesn't explain why this is true. It seems to be an odd coincidence.
Could somebody explain me the following:
According to GR time dilation due to gravitational field is expressed as:
T_{g}=T_{f}*\sqrt{1-\frac{2GM}{rc^{2}}}
where Tg is time with gravitation,
Tf is time somewhere without gravitation
G - gravitational constant
M -...
How does one go about finding what the gravitational time dilation is from the metric? Is it simply t'/t_0=1/\sqrt{g_{tt}}? It seems that could be true for static metrics, but perhaps not more dynamic ones like the Kerr metric. My confusion on this arises on how to treat the time cross terms...
Hi, I understand that according to general relativity the time dilation experienced due to gravity gets more significant the more you go down in a gravitational well, so the maximum should be at the center of the mass. But I can't really rhyme that idea with the idea that the time dilation has...
Disclaimer: I am relatively illiterate on the subject so please try to keep explanations generally understandable. Aerospace undergrad programs get zero exposure to relativity I suppose.
[Gravitational Time Dilation]
First I want to know if I am correct in saying that the gravitational...
Looking at the two equations for time dilation they seem very similar
$$t_{surface} = t_{space} \sqrt{1-\frac{2GM}{rc^2}}$$
$$t_{moving} = t_{observer}\sqrt{1-\frac{v^2}{c^2}}$$
I was hoping someone could explain more how they are connected?
I'd like to think that a fast moving object...
Question: Why is the Bailey et. al. (1977) muon storage ring experiment not considered a refutation of GR, rather than being a corroboration of SR theory?
It seems to establish that only velocity is the cause of time dilation, and the very high acceleration (order of 10^18g) plays no part in...
I have been working on something and I want to see if you guys get the same result. Let's say we have a hovering observer at r from a large gravitating body such as the sun. The gravitational time dilation there would be z_r = sqrt(1 - 2 G M / (r c^2)), correct? If a clock directly passes the...
Consider the following, from the prospective of General Relativity:
A photon's path between two points, point O (emitted point, from galaxy GO) to point R (received point, in Galaxy GR):
O: point of photon's origin, in space
GFO: gravitational field force at point O, due to its position in...
Let's say I had built a machine that is able to slow down time (Travel to the future) by one eighth. If the object creates a non rotating sphere using lasers and it is able to accomplish this task, would the time dilation be stronger in the machine or out of the machine?
I imagine I have two clocks that are synchronised and are sitting a long way from a large massive body. I hold on to clock A and let clock B fall towards the mass. Let's assume that the falling clock B gets close to the massive body but somehow misses it, swings around and travels back to me...
I (think I) understand that:
1. With the Schwarzschild metric, the ratio of proper time to coordinate time decreases ("clock runs slower") with decreasing radial distance. (And ratio of proper distance to coordinate distance increases.)
2. The geodesic path followed by a freely falling...
While gravitational redshift refers to what is seen, gravitational time dilation refers to what is deduced to be "really" happening once observational effects are taken into account.
When using special relativity's relativistic Doppler relationships to calculate the change in energy and...
Thought experiment:
Say for instance that a Baseball game is being played out on a planet that is orbiting the outer edge of a black hole. You, from deep in space away from any gravitational source, are watching this game from a powerful telescope. The batter comes up to bat; the pitcher...
According to general relativity, objects in a strong uniform gravitational field experience time slower that objects in a weak uniform gravitational field.
Does this mean that my feet, being closer to the Earth that my head, are younger than my head when I die?
If this is correct could someone...
Einstein introduced the concept of gravitational time dilation.
I get the impression that it was determined to be a consequence of gravitational red-shift.
Can anybody tell me the logical reason why gravitational time dilation follows on from gravitational red-shift?
Or was the existence of...
In the current mainstream theory of black holes, there exists a singularity of infinite density. However, it seems to me that matter actually could not compress tightly enough to reach this point. As matter coalesces in a black hole, space-time would increasingly curve. As the density...
I am simply looking for the formula to work out the time dilation on cylinders with uniform density. Also, any links to arbitrary precision calculators would be appreciated.
According to Einstein's Gravitational Time Dilation, if an oscillating physical system is elevated to a height H above the Earth then it oscillates at a higher frequency than the same system at ground level.
According to Planck's relation between energy and frequency this surely means that...
Hi All
I whish to know how much longer an atomic clock will run on the moon than it does on the earth. Considering time on Earth for 1 second, I know it will be very slightly longer on the moon. How much longer is my question, or maybe an equation. Don't consider the travel there, start...
I'm looking at this equation for gravitational time dilation:
T = \frac{T_0}{\sqrt{1 - (2GM / rc^2)}}
I understand the relation of time dilation and velocity, and how v must be less than c, but I don't understand what exactly is implied here. At a certain point, M could be great...
https://www.physicsforums.com/showthread.php?t=433866" that relativistic time dilation does not depend on acceleration, i.e. that there are instances where the acceleration might be zero while there would be significant time dilation. The example in the other thread was gravity and acceleration...
According to Einstein's Gravitational Time Dilation, if an oscillating physical system is elevated to a height H above the Earth then in oscillates at a higher frequency than the same system at ground level.
According to Planck's relation between Energy and frequency this must mean that the...
A radius is required for this relativistic formula:
t=\frac{1}{\sqrt{1-\frac{2GM}{Rc^2}}}
However, I notice that some objects are not spherical. Because of this, I am unsure of how to calculate gravitational time dilation for different shapes.
Could somebody help me with this and provide...
If as a result of the equivalence principle we can derive the gravitational red shift entirely from the perspective of an accelerating body with no reference to gravity and no reference to gravitational time dilation then one is essentially just working out the Doppler shift of a signal...
I have to learn about general relativity and to understand that, I need to know gravitational time dilation.
I heard that time on Earth and time in space is different by few nanoseconds.
How can time be different? Why does time go slowly in certain gravitational fields?
Also, how can...
I was watching the new show "Into the Universe with Stephen Hawking", and I found myself a little annoyed by his contrast of gravitational vs velocity time dilation. It was stated that if you took a spaceship, orbiting around a super massive black hole, you'd only get a 2:1 time dilation...
Homework Statement
Calculate the difference in time after one year between a clock at Earth's surface and a clock on a satellite orbiting at 300 km above the surface
Homework Equations
T = T0 / (1 - 2gR/c^2)^.5
That is, this...
The quotes below (in blue) are from another thread https://www.physicsforums.com/showthread.php?t=364893&page=5" , but since they are a slight digression from the topic of the original thread, I have decided to continue the conversation in this new thread.
Yes, that it what I am talking...
i'm 21, my bf is 20, but my parents won't allow me to marry a younger man...so is there anyway, i can use the idea of general relativity to slow down my aging relative to my bf, so that we both reach 25 at the same time?
here's what i know so far:
i understand that if I'm one floor above my...
I were trying to figure out the "logic" why gravitation (acceleration) causes time dilation.
While at "velocity time dilation" its because (e.g) light in light clocks must travel longer distances.
As seen on those pics:
http://en.wikipedia.org/wiki/File:Time-dilation-001.svg...
First, a simple scenario to set our expectations:
Consider a "stationary" massless non-relativistic test particle in empty space. We'll call the particle "P". At a very large proper distance to the cosmological "west" of P there is a neutron star, at proper rest relative to P. Let's call...
Okay, this is a hard question to phrase, so I apologise if I'm off course somewhere. One could say our world around us is built up in different levels. We live down here on a planet, orbiting around a star, flowing around a galaxy and so on. What I'm wondering is how time would be effected...
Hey everyone, recently I watched a discovery program about time travel. I understood time travel from the view point of traveling at/close to the speed of light, however, I am completely confused as to how time travel is possible using gravity.
I know that it has to do with gravitational...
I'm reading in a textbook (Gravity by J. Hartle) that gravitational time dilation is implied by the equivalence principle. The following thought experiment is described. A vertical rocket at rest in a uniform gravitational field (no tidal effects) is compared to a rocket constantly...
Consider a theoretical nonrotating solid massive ball of constant density. A shaft is drilled from a point on the surface down to the center. A light source on the surface is aimed down the shaft. Observers at each end of the shaft carry clocks which initially were synchronized before...
Based on recommendations here, I'm reading Kip Thorne's BLACK HOLES AND TIME WARPS which was somewhat uninteresting during the first 100 pages or so but then he redeems himself...here's some excerpts I found insightful and clearly stated (pgs 130-133) After noting that time moves more slowly at...
Hello,
I am new to the site and have question. I have three clocks (a,b,c). Clock a is placed on top of a mountain, 6000 ft higher than clock b, which is at sea level. Now I know that clock a will run slower than clock b. Now if were to dig a hole 6000ft below sea level and place clock c...