Questions tagged [time-dilation]

Question on time dilation, a physics concept about changes in the passage of time, caused by general relativity.

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Most time dilation possible outside of the event horizon?

What is the most time dilation possible outside of the event horizon of a black hole with the reference to us? I know that time dilation is stronger if you are near an extreme amout of mass. It is ...
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Is gravity affected by time dilation? [closed]

I just thought about what time realy is but I can't put my head around this so I was thinking that if time dilation happens at the edge of a black hole that just everything gets slower. But does ...
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Lunar Eclipse and relativity

I am currently working on A Depth Study for my year 12 Physics class, and am looking at relativity and time dilation of a lunar eclipse experience on the moon compared to as seen from on Earth. From ...
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Why are there not yet any instruments dedicated to registering time dilation caused by passing gravitational waves?

Why are there not yet any instruments dedicated to registering time dilation caused by passing gravitational waves? Wouldn't it be interesting to augment LIGO/Virgo capturing of space distortion with ...
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Gravitational time dilation

Did clocks run more slowly in the early universe due to gravitational time dilation? Or, alternatively, do they appear to be running more slowly when observed from today, if that is not the same thing?...
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How fast would an observer have to travel in order to be able to study an entire star's life in one human lifetime?

Humans live for about 80 years. A star, however, lives from 1 million to trillions of years, depending on its mass. If humans want to have a detailed study of the life of a $1 M_\odot$ star, how fast ...
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Would studying massive stars that are experiencing time dilation due to proximity to a black hole be useful?

I saw this question (Could a star closely orbit a black hole long enough for the star to have lost 0.5B+ years to time dilation?) and came up with an interesting thought. Massive stars live for less ...
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Boltzmann brains - probability [closed]

A question about the Boltzmann brains assuming heat death of the Universe. It is said that if so, than it's more likely were are such constructs instead of having reality as we perceive it, however it ...
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What is the age of the universe if you were standing in a galaxy far far away such as GN-Z11?

If we agree with the universe starting from a Big Bang, 13.8 billion years ago, expanding at different rates governed by the Hubble constant of 67.4 km/s/Mpec, somewhere about 13.4 billion light years ...
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Where do the photons come from at the edge of an Event Horizon?

I was reading about Professor Finkelstein's speech at Cambridge University back in the 50's. He was explaining the dual reference frame of a black hole's event horizon. (A person falling in has one ...
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Is there any planet or black hole where we could experience time dilation like in the movie Interstellar?

As we seen in Interstellar movie Copper goes to a planet where he experienced time dilation which was 1 hour of staying on that planet will cost the 7 years on the earth. So, is there any planet or ...
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Does time also pass more slowly for a galaxy that is traveling at relativistic speeds, where the speed difference is due to Hubble expansion?

If time passes more slowly, relative to Earth, for a traveler at relativistic speeds, say at .8c, traveling between stars inside this galaxy, does time also pass more slowly for a distant galaxy that ...
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Why does time pass faster in moon than the earth?

One of my friends said that, time passes faster in moon than the earth Why does time pass faster on the moon than on the earth?
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Must time pass more slowly, relative to our inertial reference frame, inside galaxies that are currently located at half way to the Hubble Horizon?

Trying to understand simultaneity of events and time-dilation on a Universe scale, I would like to know must time pass more slowly, right now, relative to our current inertial reference frame, inside ...
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Thinking about the Twin Paradox, what would a Twin Traveling at .8c, calculate as the amount his EBT aged at the mid-point in a 4 lightyear trip? [closed]

Referring to the twin paradox, where we have an Earth Bound Twin “EBT” and a Traveling Twin “TT” who travels away from Earth at velocity= .8c, lets say to Alpha Centauri, when the TT is half way ...
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is there a way to determine a distant galaxy’s speed relative to the Hubble Flow by measuring time dilation effects between there and this galaxy?

As I understand it there is a preferred frame of reference based on the velocity for the CMB and our galaxy is moving in relation to it (at about 600 km/s). I think this is how the Hubble Flow is ...
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How much time passes in the outside universe when falling into a black hole?

If someone were to jump into a black hole, looking back at Earth, how far into the future would they see of Earth? As I understand it, time would dilate approaching infinity as you approach the event ...
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How does gravity affect a physical clock?

In all the explanations for time dilation and how gravity affects time a common example which is used is "Clock near to the ground will tick away faster than clock away from the ground due to gravity"....
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What reference frame do age-of-the-universe calculations assume?

I'm thinking, in particular, about general relativity. When we speak, for example, of neutrino decoupling, what do we mean when we say this happened in the first second after the Big Bang? Do we mean ...
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Could a star closely orbit a black hole long enough for the star to have lost 0.5B+ years to time dilation?

I was wondering how stable a close star-black hole system could plausibly be, and thus how much time a star could plausibly miss out on (from an outside observer's perspective) due to being in an ...
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Whats the time dilation difference between the earths reference and (near) the milky way galaxy central black hole? [duplicate]

How much difference in time is there between our time of reference and very near the black hole at the center of our galaxy. I was trying to get answer in terms of something like "1 year in here ...
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Does Gravitational Time Dilation stack on top of Time Dilation caused by Velocity?

Using 1 CM from the Event Horizon of Super Massive Black Hole, SGR A, as the reference point. The particles within the accretion disk are traveling at extreme high speeds. Assume this speed increases ...
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Cosmological redshift - How do we know it's not caused by the observer's time dilation?

Instead of cosmological redshift being caused by the metric expansion of space, why couldn't cosmological redshift be caused by our perspective moving faster in time? Said another way, if the ...
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How does time dilation from a large body fall off? [closed]

A magnetic fields generally fall off as 1 / r^3 rather than 1 / r^2 for gravity. How does time dilation fall off from a large body? Where would the gravity and magnetic field line be in this chart ...
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If I could see from a Gravitational-Time dilated place to somewhere far which is not dilated, would I see fast moving people?

Gravitational time dilation like the one shown in the movie Interstellar, causes time to move slowly for someone within the high gravity reference frame. Now let's say that from such a place, I was ...
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Universe is expanding, why doesn't time expand with it?

Reading this response When the universe expands does it create new space, matter, or something else? I understand Universe is not expanding like if it is stretching its space, but it is actually ...
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Can anyone one show how speeds greater than c cause a paradox on a space time diagram?

So according to Relativity, time moves at different rates for different observers, and distant observers will actually disagree on the order of events. Now from what I gather this gets sorted out for ...
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What is this "time travel" these popular blogs refer to?

I am getting confused by some "popular science" about time travel, such as or "Time Travel Is Real. Here Are the People and Spacecraft Who Have Done It": It is indeed an interesting property of ...
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How to convert factors of time dilation into something relatable? [duplicate]

On this post, Time according to the gravity of Sagittarius A? They found the factor of time on the varying distances from the SMBH, I am curious on how to turn those factors into relatable terms ...
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Does time dilation increase within overlapping gravitational fields?

If a spaceship was to travel to the barycenter of a binary star (the stars having identical size and mass) and come to a stop there, would the people on board this spaceship find that time is moving ...
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Black-hole becoming a star again - follow-up question [closed]

Some questions have been posed about black holes becoming stars again once they attract enough hydrogen/atomic matter from another star. Some answers were a forceful NO. Never. However - let's ponder ...
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What if one teleportes to a star that is some light years away? [closed]

When we see a star from the earth that is 5 light years away, we are essentially looking at light emitted from the star 5 years ago. What if you were to instantly reach near the star, either by ...
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What would a black hole merger look like?

Ship 1 is out side the black hole. Ship 2 is nearing a black hole. To ship 1 it would appear that ship 2 would be moving slower to the point it would seem like ship 2 stopped moving the closer to the ...
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Gravitational eddies across the galaxy?

I read about natural gravitational eddies that travel in a wave that black holes have. They also have a strong magnetic field. Does those eddies follow magnetic field lines of the rotating black hole? ...
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If you looked at Earth while travelling at relativistic speeds, will you see sped-up activities?

Suppose you traveled off Earth and back at relativistic speeds, so that when you come back much longer time elapsed on Earth than you experienced. Suppose you had an excellent telescope through which ...
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How do I imagine time difference?

I could never understand how in Interstellar, they say our every hour spent on the planet is equal to 7 years on Earth and when he returns back to her daughter, the father is older than her daughter. ...
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Could a closely orbiting pulsar be used to study a black hole?

If we were to locate a pulsar in a close elliptical orbit around a black hole, could this reveal significant information about the black hole (e.g. time dilation / structure)? Could this even tell us ...
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How long would a near-light-speed trip to proxima centauri take from the traveler's and the earth-observer's perspectives?

Lets say the spaceship is traveling at .9c to Proxima Centauri. How long does this trip take from the observational standpoint of the passenger vs. the observer from Earth?
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Will biological process be disrupted under strong gravitational time dilation?

This question is raised by someone I've discussed with, after watching the movie "Interstellar", in which a clip showing Cooper and Amelia landing on Miller's planet near a super-massive blackhole and ...
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What effect does time dilation have on bodies orbiting close to Black Holes?

As far as my (somewhat basic) knowledge of astrophysics goes in general the closer to a star your orbit gets smaller (because you travel less distance) and faster (because you're deeper in the gravity ...
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What is the oldest thing?

I'm well aware of the celestial bodies considered as the oldest visible in our galaxy. My question might feel a bit odd: What is the oldest thing in the universe? I am puzzled with this question as ...
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absolute speed of bodies as observed by a distant observer

What does a distant observer see if two masses with a given velocity are close enough to each other that time is dilated ? Scenario (using 2 point masses for simplicities sake): Mass a: 1,00E+030 kg ...
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What does the coordinate of time really mean?

The meaning of the $t$ which appears in space-time intervals or metrics in general relativity. I concluded that $t$ was just a mathematical thing which allows us to label the "space-time manifold" and ...
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How can a black hole ever form? [duplicate]

We know that an object falling to the black hole, as observed from an observer far away, will freeze as it gets closer and closer to the event horizon. So my question is how can a black hole form in ...
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Black hole darkness a result of gravity or temporal distortion?

Please correct me if I am wrong as I may have made some incorrect assumptions. Okay so we know that at some stage of "nearness to a black hole", light is no longer reflected back at us from the black ...
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How long would it take to reach the edge of the reachable universe?

How long would it take to reach the current edge of the reachable portion of the universe, with the following bounds in mind: We figure out a way build a space ship to provide a constant 1 G ...
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gravitational time dilation multiple sources

I wondered how time would be dilated for an object in the middle of 2 black holes, however https://en.wikipedia.org/wiki/Gravitational_time_dilation only provides a formula for one source of gravity ...
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How far into the future can we go by traveling close to a black hole?

If we sent someone on a path that passed as near as possible to a black hole without getting pulled in, how far into the future would they go due to time dilation? Let's assume the black hole is 5 ...
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When you travel fast around a black hole, do you experience high speed yourself?

When an object in the space comes close to a massive body (like a black hole or a neutron star), we see from Earth that its speed significantly increases while it is close to the body. As we know, ...
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How does time "add up" for observers outside of and travelers inside of a Krasnikov tube?

A ship travels 99% of c from Earth (leaving at Time A, say 2016) to Destination Star (arriving at Time B, say 2020, accounting for relativistic effects) to stretch the tube, leaves a buoy at ...