What is Relativity of time: Definition and 22 Discussions

The theory of relativity usually encompasses two interrelated theories by Albert Einstein: special relativity and general relativity, proposed and published in 1905 and 1915, respectively. Special relativity applies to all physical phenomena in the absence of gravity. General relativity explains the law of gravitation and its relation to other forces of nature. It applies to the cosmological and astrophysical realm, including astronomy.The theory transformed theoretical physics and astronomy during the 20th century, superseding a 200-year-old theory of mechanics created primarily by Isaac Newton. It introduced concepts including spacetime as a unified entity of space and time, relativity of simultaneity, kinematic and gravitational time dilation, and length contraction. In the field of physics, relativity improved the science of elementary particles and their fundamental interactions, along with ushering in the nuclear age. With relativity, cosmology and astrophysics predicted extraordinary astronomical phenomena such as neutron stars, black holes, and gravitational waves.

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  1. diazdaiz

    B Help Me Determine Validity of Time Dilation Formula

    I recently trying to learn General Relativity by first scraping the surface on ScienceClic's general relativity playlist, and then I stumbled upon a video where it said that we actually move through spacetime on a constant speed of c, and then I remember about time dilation because how speed on...
  2. alexandrinushka

    B Any plausible explanation for dynamical length contraction?

    I am new here, so pardon my ignorance. First of all, I am aware of the impossibility to distinguish experimentally between SR (Special Relativity) and LET (Lorentz Ether Theory). I know there is a PF policy article on LET and the Block Universe. I must admit though that LET is more appealing...
  3. Buckethead

    B Paradox in the block universe interpretation

    Consider two observers, Alice and Bob, standing on the Earth together with synchronized clocks. Bob asks Alice, “Is this now?” to which Alice replies, “Yes, it is”. They are clearly both in the present moment. Bob climbs a mountain and some time later, due to the lower gravitational field...
  4. R

    I Relativity of Time for Two Observers

    I have the following dilemma and ask for advice: Observer A is swings on the springs, while the observer B is stationary nearby. (See diagram: http://www.frozman.si/slike/Vzmet.jpg ) According to the theory of relativity to observer A the time flows slower due to its speed (as in the paradox...
  5. S

    On the relativity of time and speed

    Speed can only be measured relative to some other object, like the speed of a tennis ball during a match at Wimbledon can only be measured relative to the ground, or a cloud, or the planet Mars. On the other hand, time is relative. An object traveling at speeds approaching the speed of light in...
  6. K

    Special relativity question: space travel and relativity of time

    Homework Statement You are 20 years old and embark on a mission to a star system that is 200 light-years away. Your ship leaves Earth in 2013 and travels at 0.999c. You do not spend much time at the destination, just head back to Earth. What year is it when you arrive back on Earth? How old...
  7. A

    Solving Special Relativity: Tom's Journey Home

    Hi! I have difficulty with the English language but will try my best. I have recently begun to study the theory of special relativity. , I understand what the relativity of time is, relativity of length and Lorentz transformations. But I still have difficulty with solving data and do not know...
  8. B

    Quantum entanglement and relativity of time

    if there are two entangled particles one of them is flying 80% the speed of light , one of them is on Earth for instance if we measure the one on Earth , would it the entanglement affect the other particle after sometime * due to time slowing down for speeding up particle * or does it happen...
  9. A

    Time & Space: Is One Relative to the Other?

    Is time relative to space, or space to time?!
  10. S

    The relativity of time and defining the age of the universe

    The relativity of time and defining the "age" of the universe I have been doing searches on the relativity of time and its relation to the "age of the universe," among other things. I have come across some insightful Q&A, but I have yet to really see a "solid" response to my innate question...
  11. J

    Quantum entanglement vs relativity of time

    I looked into quantum entanglement thing last days and I think I got it right. At least the basics. Just one thing. Quantum entanglement concept says that when I measure the state of one particle, it affects the entangled one's state instantly. But what does this have to do with the...
  12. T

    How Does Gravity Work and What Causes Time to Slow Down Near a Black Hole?

    About relativity of time. It can be noticed already in Earth in vertical time measurements. But how long it continues. So what will happen in black hole to time. Gravity is unlimited, so ticks will slow down. And other thing, speed slows down the time. So in huge gravity, all speed will...
  13. O

    Relativity of Time and Length

    Homework Statement A race horse can travel down a 2000m straightaway at a speed of 0.9c. a) How long does it take the horse to run the straightaway according to a timer sitting in the grandstand? b) From the jockey's perspective, the length of the straightaway appears to be less than 2000...
  14. G

    Understanding the Twin Paradox: Breaking the Symmetry in Time Dilation

    So what I've heard so far is that if you're in a spaceship and you're moving at a speed close to the speed of light relative to the Earth then what seems like 1 hour for you could be something like 1 million years for people on earth. This made sense to me until I realized you're moving relative...
  15. J

    The relativity of time: time dilation

    QUESTION #1: 1. suppose a race on Earth was monitored by a spaceship traveling in space at 0.900c relative to the Earth and the space travelers measured the time of the race to be 125.6s. What was the time recorded on earth? 2. t = gamma t' where gamma = 1/ sqrt(1-v squared/c squared) 3. v...
  16. M

    The relativity of time: Time dilation

    Homework Statement Suppose that you are traveling on board a spacecraft that is moving with respect to the Earth at a speed of 0.925c. You are breathing at a rate of 10.0 breaths per minute. As monitored on earth, what is your breathing rate in breaths per minute? Homework Equations...
  17. M

    Important note concerning relativity of time

    Resnick on pages 470 and 471 in Physics (4th edition) states that T = t/sqrt(1 - v^2 / c^2), where T is the time value (of an event) obtained by an observer using a moving clock, and t the value of the same event using a stationary clock. But A. Einstein on page 49 in The Principle of...
  18. M

    Time Dilation: Exploring Relativity and the Perception of Time

    it is now in my watch 8:02 pm (8/29/2006) in burbank, california. this time is between 8:00 pm thru 9:00 pm. i observe that this period of time is 3600 s according to my wrist watch. but according to a watch (which is synchronized with my watch) moving at 0.9c relative to me, i would have...
  19. H

    Time Is Relative: What Does It Mean?

    Hi, my old physics teacher once told me that time is relative. But what does "time is relative" actually mean? Does time depend on something? Thanks in advance!
  20. R

    The Logic Behind Einstein's Relativity of Time

    This is my first post here. I have been trying to understand the logic behind the exclaimation that time is relative. To this moment I have failed. I guess I need some additional information in order to do this so I ask for your help. As it looks to me now Einstein has merely proven that...
  21. M

    Proving Relativity of Time with Slow Movement

    ok I am a little stuck on this problem, I am hoping some one can help me out One way to set up the system of synchronized clocks would be for the chief observer to summon all her helpers to the origin O and syncronize their clocks, and have them travel to their assigned positions very...
  22. C

    Exploring the Relativity of Time with VSL

    Ok, I'm currently reading a book about VSL and it mentions relativity at the beginning, and while reading I couldn't help but wonder something... in a nutshell it says that since light has a finite speed (and not infinite), time must be relative. It gives the example of how when cows who stand...