Time Definition and 1000 Threads

Experiment 1: Astronaut travels away from Earth at near the speed of light, then travels toward the Earth at near the speed of light. Einstein tells us she barely aged, but red shift/blue shift don't seem to agree with that. While traveling away, both Earth and astronaut observe each other...

Forgive me, I am not a probability guy, so I am unsure how well known this is. I was trying to figure something out and found this. I found it cool. Here's the explanation. The first solution is a fraction (damn scanner!) Oops! From Kendall Geometrical Probability (1963)

Time is money. Stocks and bonds are also money. Stocks have momentum, and thus time, which is equivalent to money, which is equivalent to stocks, has momentum, and therefore inertia. Time is also space, of course, space costs a lot of money, as does space travel. Especially space travel to...

I tried in the first place to use the effective potential of a parabolic orbit which is 0 to get the angular momentum L. Evaluating the function U(r) at r = rP i get U(rP) = L^2/(2m(rP)^2) - GmM/rP = 0. Here I get L = m√(2GMrP). Now the relationship between angular momentum L and areal...

Hello, why time is the fourth dimention and not another quantity or variable? General relativity has as a special case the special relativity, so Lorentz transformations are contained in general relativity but are they in a more general form than that of special relativity generally? If they...

I am a little confused with the concept of proper time: Using the invariance of the distance square in the Minkowski space, we can get the expression ##d \tau = \frac{d t}{ \gamma}## Now the problem: Aren't the proper time the time measured by a moving clock? That is, if i am moving with speed...

I thought the answer was no. I.e. the traveler's proper time always passes more slowly than a stationary observer's clock regardless of the traveler's direction with respect to the observer. I was watching Brian Greene's NOVA episode on time, however, and, at 23:15, he has a demonstration...

So picture this, its 2500 and you want to time travel back to 2300 to kill your great grandfather, this obviously creates a paradox wherein you prevent yourself from being born right? Well why don't you use your year 2500 technology to create a clone of your grandfather to replace him after (or...

I have one question I hope someone here can answer for me. Relativity theory tells us that space and time are sort of the same thing, as a spacetime. So when space is expanding, what happens to time? I find it hard to believe that time is somehow unaffected by the expansion of space, so while...

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...

In Box 2.4 of the book "Black Holes & Time Warps" by Kip S. Thorne, he explains gravitational time dilation using the equivalence principle. For this he uses an experiment thought analogous to the one used by Einstein in 1911 to postulate the existence of a gravitational Doppler shift, but...

Please refer to the homework statement. Or, if one would like to put it in other words, how would I go about finding ##T_2## if I know the delay time between 90-degree and 180-degree pulses? Is there an equation that helps solve this succinctly?

I am trying to understand my results for my muon experiment. I conducted the experiment using a plastic scintillator photomultiplier detector. I have four different data sets, with different discriminator thresholds: 148 mV, 190 mV, 260 mV and 550 mV. I made a histogram of the counts of all four...

I know for muons that the the probability that a muon decays in some small time interval ##dt## is ##\lambda dt##, where ##\lambda## is a decay rate. Thus the change in the population of muons is just ##dN/N(t) = −\lambda dt##. Integrating gives ##N(t) = N_0 \exp(−\lambda t)##. This makes sense...

I get the first part of B, but why doesn't the transported direction not change as the electric field changes? Does it follow the right-hand rule?

(1) I remember reading somewhere that in general relativity, "space" and "time" lose their metrical meanings. Is that true? And yet, we continue talking of space and time in general relativity as spacetime. (2) Moreover, as someone mentioned in this thread, what happens to the speed of light? In...

Other than a brine, which will penetrate and tenderize meat, marinating does nothing: https://www.splendidtable.org/story/2017/06/02/food-myths-busted-by-americas-test-kitchen-marinating-basting-and-boiling Article also says basting Turkeys is pointless

time = x(min) distance = 1(y) y = unknown unitsI think the answer should be 1(y)/ Min. This is not correct becase 1(y) is unknown. Any help? I have the answer but am confused

The International Bureau of Weights and Measures combines the readings of 450 atomic clocks around the world to obtain a time standard with sub-nanosecond accuracy. These clocks run at different rates - a clock at 1 km of altitude gains about 7 ns a day compared to one at sea level due to the...

I'm reading through Stephen Hawking's 'A Brief History of Time' and came across this sentence in the second chapter: " If the law were that the gravitational attraction of a star went down faster or increased more rapidly with distance, the orbits of the planets would not be elliptical, they...

A 7.80 g bullet is initially moving at 500 m/s just before it penetrates a block of solid rubber to a depth of 4.50 cm. (a)What is the magnitude of the average frictional force (in N) that is exerted on the bullet while it is moving through the block of solid rubber? Use work and energy...

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...

Edit: Picture of the Circuit (Simple RL circuit) The value of L is not given. Attempt to Solve for T by Rearranging Equation 1: I rearranged the equation to solve for T, using Ohm's Law so solve for I = V/R at each time. https://www.desmos.com/calculator/qlb2n6w4bg This graph is...

$$d\tau = \sqrt{-g_{\mu v}\frac{dx^{\mu}}{d\lambda} \frac{dx^{v}}{d \lambda}} d \lambda $$ Calling ##d \lambda = d t##, t is coordinate time in an inertial frame. $$\Delta \tau = \int \sqrt{-(-1+v^2/c^2)} dt$$ $$\Delta \tau \approx \Delta t - \frac{g^2*\Delta t^2}{6c^2}$$ where $$\Delta t = 2...

Sorry, for the lack of correct terminology - this may be answered elsewhere on the forum, I haven't been able to find it. If the Universe is in Einstein's 'Block Time', then does this provide a mechanism for 'action at a distance'? Rather than a particle being split and entangled, if viewed...

Hi folks, a question regarding the value of G, has there been an experimental data collected on the value of G over time, what I'm interested in, is if the value of G in the observable universe, is decreasing or increasing (by a small amount) over time, thanks.

Hi, I'm wondering about time. Time is very important in physics. It seems we inherited the idea of 60 minutes in an hour from the Babylonians. I don't know if the Babylonians were even interested in minutes, let alone seconds, probably not. Later on, we needed more accuracy, I suppose it...

The speed limits on a straight road are given by a known function g(x,t) where x is the location on the road and t is time. A car starts at x = 0 at time t= 0 and always drives at the speed limit. The location of the car is given by the (unknown) function s(t). Is there a differential...

Hi I would like to transform the S-parameter responce, collected from a Vector Network Analyzer (VNA), in time domain by using the Inverse Fast Fourier Transform (IFFT) . I use MATLAB IFFT function to do this and the response looks correct, the problem is that I do not manage to the time scaling...

Attached is the problem and my work through the problem. I got the problem correct, but my teacher said this could be done quicker on a calculator. Any idea how it could be done quicker.

In a thread I started awhile back, in the common twins paradox scenario, it was indicated to me that the actual time (paraphrasing) on Earth for any given time in the ship is basically “undefined” (as it can’t be verified) and/or time dilated (ticking slower) for the trip out and then shifted to...

https://dst-public.s3-us-west-2.amazonaws.com/lagrangian.png

Dear everybody, Let me ask a question regarding the unitary time evolution of a given Hamiltonian. Let's start by considering a Hamiltonian of the form ##H(t) = H_0 + V(t)##. Then, I move to the interaction picture where the Schrödinger equation is written as $$ i\hbar \frac{d}{dt}...

This example is worked out in the book, and at the beginning, they make the assumption that the muon is traveling 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 for...

Hi, I am not sure what the correct forum is for this question. Question: When do we need to remove seasonality from time series data to do a regression analysis? Context: I am planning to conduct a prediction analysis where I want to find out how a device performs. I hope to estimate a...

Originally I had thought this was a normal question and simply did the normal s = (1/2)at2, which got the answer of about 0.4s. The answer is however 0.9s, so I double checked the diagram. The right tail of M is tied to the string connecting m, and two strings connects the top of M to the...

This is more of a conceptual question. To find the horizontal velocity as a function of time for the above wave function, you take its partial t derivative and insert x=4. In other words the function would be -2.4sin(1-12t). Im wondering why you take the partial t derivative and not to partial...

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...

Homework Statement:: time step must be greater than stability criterion Relevant Equations:: stability criterion= h^2/4 x alpha Hello. I have had to do 2 MATLAB codes based on the 2D Heat diffusion equation using the Explicit Finite Method. In those codes, the time step must be greater or...

As a starting point I immediately thought about the equation: ##\frac{dp^\mu}{d\tau}=qF^{\mu\nu}v_\nu## From this I proceed component by component: ##\frac{dp^0}{d\tau}=qF^{0\nu}v_\nu=q\gamma E_yv_y## ##\frac{dp^1}{d\tau}=qF^{1\nu}v_\nu=q\gamma v_yB_z##...

I have just finished reading The Order of Time by Carlo Rovelli and From Eternity to Here by Sean Carroll. I feel I finally understand that time is simply thermal entropy, but they both also talk about space-time and how time slows under gravity and at high speed. If time is just an illusion as...

I'm interested in knowing where can i find the information on decay time of (possibly every?) different type of bosons, hadrons and fermions, which is available to the public (tiletles of books, articles, ...). Any suggestions or ideas?

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...

Consider instead a thermally insulated container of volume V with a small hole of area A, containing a gas with molecular mass m. At time t = 0, the density is ##n_0## and temperature is ##T_0##. As gas effuses out through a small hole, both density and temperature inside the container will...

I already how to properly set it up and execute the equation with natural log etc. 2/3q0 = q0e^(t/RC) 2/3 = e^(-t/tau) ln(2/3) = -t/tau t = -ln(2/3)tauThe problem should be trivial; however, -ln(2/3)tau is apparently incorrect. So is ln(3/2). Is there something I am missing?

I am curious about time traveling. According to Einstein's special relativity, the easiest way to travel into the future is by approaching the speed of light or faster. Now assume this setup: Sunlight travels to Earth at c (speed of light). We have the technology to reach speeds faster than...

since, in order to view the shape changes in our wave packet we are presented with the taylor expansion of the frequency ω(k) = ω(k0) + (k − k0)dω/dk + 1/2*(k − k0)^2 (d^2ω/dk^2) we are told that only the third term that is the 1/2*(k − k0)^2 (d^2ω/dk^2) contributes to change in shape of the...

I'm working on a problem which can be CPU-intensive and was wondering what it would take for me to get time on a supercomputer to run it and if so, how would the speed of a typical supercomputer compare to my 4.5 GHz machine? It's a relatively simple Mathematica program to find polynomial...

Summary:: Special relativity - 2 astronauts syncronize their clocks and moves in different paths at different velocities, which clocks is left behind? and why? Hi everyone, i have the following problem and I'm not understanding if my strategy to solve it is correct: Two astronauts synchronize...

We can find that (1+e)/(1-e) = 8 => 1+e = 8 - 8e => 9e=7 => e=7/9. I'm not sure if I need this. We can also find the time period of Earth ## T=\frac{2 \pi r}{v} = 3.14* 10^7 s## I think I need more information from somewhere else. What am I missing?