1. ### B Clocks Vanishing into Thin Air - Gravitational Time Dilation

With regard to relativity of simultaneity and the "block" universe and reflecting on the notion of skewed time slices associated with frames moving relative to each other, one observer sees one event a distance away (parallel to the direction of motion) occurring before another event a distance...
2. ### B Why Aren’t ALL SR Effects Cumulative?

Why aren’t all the SR effects cumulative like Time Dilation? Why should the Space dimensional effect become null when v—>0 while the Time dimension does not revert back to the 2 frames being in sync if Space and Time are treated on an equal footing. Clearly, Space and Time are not treated on an...
3. M

Good day. I have read many books, forums, and articles, and watched many youtube videos, all in an effort to understand special relativity and time dilation. Or rather, more precisely, trying to find a valid explanation that does not result in contradictions and paradoxes, and if it does, one...
4. ### Intro special relativity problem regarding time dilation

This example is worked out in the book, and at the beginning, they make the assumption that the muon is travelling at c, and then find the change in time from the Earth reference frame using delta t=100km/c. Then delta t is plugged into the time dilation equation on the left side and we solve...
5. ### Calculate time passed on a ship clock seen by Earth observers

In this case, γ = 1/√(1-v^2/c^2) = √(1-0.6^2) = 0.8 However, I'm not sure if time observed by Earth is proper time or moving time. The definition of proper time in my textbook states that it is 'the time measured in a frame of reference where the events occur at the same points in space. I'm...
6. ### I Time dilation and the galaxy rotation curve

Hello, What I understood from multiple answers on different threads is that the effect of the time dilation is too small to explain the galaxy rotation curve. I was advised to do some calculations in order to see it myself. And this is what I would like to do but I need some help. - What is...
7. ### Ideas for novel I'm writing! I would love some insight on a concept!

Summary:: Ideas for a novel I want to begin writing. Brainstorming ideas and need help with a certain concept. Any help is appreciated! Hello to you all, this is my first post, and I Google searched this astrophysics forum because I thought it might be a good place to begin asking for advice...
8. ### B Why do you need a light clock?

what is wrong with the thought experiment below?! If I consider a light beam going straight towards an observer in motion it makes it look the moving clock ticks faster, but if you use a light clock it makes it look like the clock turns slower. What am I missing here? “Two observers convene in...
9. ### I A version of the twin paradox without accelerations

Bob is standing on Earth and Alice is on a distant planet at a constant distance from Earth. Their watches are already synchronized in the following sense: Suppose Alice's planet is a light-year away from Earth. Bob emits a light signal to Alice at time t = 0 according to Bob's watch. When Alice...
10. ### Transforming Y-axis table values into a separate formula?

Hey everyone, I have generated a nice little velocity vs time graph that I would love if somebody could help me put to use. I have marked data points on the x-axis for the Y-value for every second on the function. Just to be clear: X-axis = time in seconds & Y-axis = velocity in meters/second...
11. ### B Does time dilation work in 1d space?

Imagine this question in 2 dimensions, time (t) and distance (x), that is (t,x). Alice (A) is at the origin, x=0. Bob (B) begins at x=c. Thus we have A(0,0) and B(0,c). Both Alice and Bob send a light signal towards the other but let's say the signal changes colour every second by the colours of...
12. ### Lorentz transformation for an approaching observer

I think this should be t'= Lorentz factor* (1+v/c)t, but that doesn't make sense to me.
13. ### B Does time exist for photons?

Do photons, I'm not sure how to express this, "experience" time? Since they move at the speed of light does time not exist for them? If time does not exist, how is it possible for anything to happen to them. If interacting with matter requires a change in their condition, how can a change in...
14. ### I Calculation of Time Dilation with Online Calculators

I m a noob, I wanted to figure out the time dilation for an observer on earth who passed 50,000 years, and the Traveler at light speed(99.9%) passed ONE DAY. I mean we pass 50,000 years on earth and the Traveler spends One day.Problem is I tried many online calculator, but each one is giving me...
15. ### B Attribution of reference frame

I can't find an answer on my dilettante question about how we attribute reference frame to complex objects, where different parts move with different velocity or where different parts experience different influence of gravitation. For example, we can take a human's body. If we take the full...
16. ### I Issue With Derivation of Gravitational Time Dilation

Why do we use the equation ##\frac {1}{2}mv^2 = \frac {GmM}{r}## to derive potential velocity, and then put that in the Lorentz factor in order to derive gravitational time dilation? Shouldn't we be using the relativistic definition of kinetic energy -> ##mc^2(\gamma - 1)## to derive the...
17. ### I Time dilation basic understanding from different perspective

So I am having some hard time understanding exactly the effect of moving near light-speed on time. Most of the examples mention clocks as a way of measurement but I can understand why would a clock which is a mechanical or electrical device for measuring time would be effected with motion. That...
18. ### How can the time dilation equation explain faster moving clocks running slower?

Since for the two events of Samir starting the stopwatch, and the stopwatch reaching 10.0s, Samir and his stopwatch are stationary from his own frame of reference, I said it was the proper time and that delta t0 = 10s. Then the speed of the moving frame of reference was 0.6c. I thought placing...
19. ### Effect of time dilation on a satellite

I've got the start of a plot forming in my mind, and I'm wondering if it's likely to be supported by physics at all. My basic understanding: when astronauts go to the International Space Station, due to the speed at which it is travelling, time passes ever-so-slightly slower for them. This...
20. ### I Gravitational time dilation and radius

(Apologies I posted this initially as a conversation. Not familiar with the format) I used the ‘gravitational time dilation’ equation to see how the clock rate varies with distance from the center of an object. I got the opposite result to what I was expecting. From Wikipedia; Gravitational...
21. ### I Calculate mass from time dilation

Based on the exponential growth of time dilation 0.0 - 1.0 if given the radius of an object how do you calculate the mass of the object? Time dilation is a function of gravity. Which can be thought of as escape velocity from a gravitational field. So if you have to achieve .866 c to escape...
22. ### B Time dilation and Einstein's theorem

Hello! Einstein's theorem is in the last sentence of the following quote (bold) : "If at the points A and B of K there are stationary clocks which, viewed in the stationary system, are synchronous; and if the clock at A is moved with the velocity v along the line AB to B, then on its...
23. ### B I got confused about SR after trying to reply to another

So let us say that there are 3 separate alien species that somehow speak and write the same language. Let us say that 2 of these have always lived and died in their spaceships/asteriod ... going at speeds close to that of light. Alien species 3. A3 leaves behind a message saying that at time t0...
24. ### B Re: Absolute Zero Velocity

You may think you've seen this before, since I've seen similar discussions in the archives of this, but I think I've distilled the thoughts down to a couple of facts that contradict the common beliefs regarding relativity. Let me preface this with a basic observation: Lorenz invariance does not...
25. ### I Questions about gravitational effects on the age of Earth's core

The Wikipedia page on gravitational time dilation (https://en.wikipedia.org/wiki/Gravitational_time_dilation) states: "Relative to Earth's age in billions of years, Earth's core is effectively 2.5 years younger than its surface." A clock subjected to less acceleration (gravitational or...
26. ### B Time Dilation

Assumption: Object 1 is moving and object 2 is static. It is impossible to say which object is moving without any reference object 3. There are three scenarios possible. 1. Reference object 3 is at same position in space time with object 2, then object 1 is moving and object 2 is static. 2...
27. ### B Take on Length Contraction at relativistic speeds

Hello everyone and apologize if my questions seem a bit off, please have patience with me. I want to have the following, rather simple, thought experiment. Let's say that we have a moving object O with the proper length L, when at rest. Let's say that object O starts moving at 0.9c (90% the...
28. ### Time Dilation in a Sci-Fi Novel

Super frustrated English major here trying to do calculus! Please help! I'm in way over my head... So, I'm writing this manuscript that involves humans with genetically inherited teleporting abilities. Near the end of the book, my protagonist wants to fling the antagonist close enough to a...
29. ### I Thinking about time dilation

Feynman Lectures 15-4 Transformation of time first para http://www.feynmanlectures.caltech.edu/I_15.html How is it possible that the moving clock slows down and also shows more time elapsed to the man outside?
30. ### I How can light have a wavelength or change direction in SR?

Hi all, I have two questions about light in Special Relativity. (I'm going to pad these questions out with a few statements about my understanding of length contraction and time dilation, so you can see how I currently think about it and clear up any misconceptions if I've got the basic idea...