Time Definition and 1000 Threads

Hello Forum, I am not sure this question really belongs here but I was not sure where else to post...it is about science and health after all. I started thinking about this question seeing so many people have sadly become homeless and living in their cars because of the pandemic and job crisis...

The faster the relative speed or the more intense the gravitational field, the slower time passes. Does it make sense to ask what both have in common that affects time? Or does the question possibly only make sense in the context of certain theories, for example the LQG, where space and time...

Hi, I just have a quick question regarding the linear phase property of filters. It might be easier to provide some context before getting to the question, but feel free to skip to the bottom. Consider a system input as a discrete sequence obtained by sampling at t = 0, T, . . . , kT from an...

Disclaimer - I am not an expert by any means so this might be as much about confirming my understanding as an inquiry from the general public... as such, it might be fairly conversational as I attempt to clearly communicate my thoughts and understanding. Please excuse this. If gravity is the...

Question --- So I've done a calculation which seems to suggest if I combine the system of a measuring apparatus to say an experimenter who "reacts" to the outcome of the the measurement versus one who does not. Then the change in entropy in both these situations is bounded by: $$ \Delta S_R...

I have a problem understanding what is going on in the region called the ergosphere of a "fast" Kerr black hole. - Relativity teaches us that no frame of reference can have relative displacements greater than the speed of light, ok. - The ergosphere of a fast Kerr black hole can contain light...

These questions normally have initial velocity = 0, so that one of the t terms cancels. In this case u = 20ms^-1 so I end up with a quadratic. Which is fine if I plug it into the quadratic formula as one result is -ve so can be ignored, while the other gives t as +ve. just wondering if this is...

My hypothesis: A sequence with the gravitational waves detected, sent by modulating radio waves, could be received and used by other intelligent beings to find the corresponding sequence within their records and then compare it to calculate our spacetime position in relation to theirs. As...

My understanding from General Relativity is that if as distant observers we watch a probe or any test mass approach a black hole, time dilation goes to infinity as the probe gets closer to the event horizon. This would imply that we would never observe a black hole form, or the collision of two...

At present i am only attempting the part a, i want to use the equation ##F=ma ; qE = ma;## ---> eq1 The electric field is given by the formula ##E = -\frac {dV} {dx} ## ##v = \frac {dx} {dt} => dx = v_0 {dt}## ---> eq2 (?) ##E = -\frac{dV} {v_0 dt}## Here ##V = -V_m \sin(\omega t) ## hence...

It is possible to derive 2 contradictory time dilation equations. The first paragraph below describes the situation with Sally aiming a flashlight straight up and down so that Sally sees the light moving straight up and down and John is outside the spaceship and sees the light forming a...

If time for something approaching the speed of light will slow down and approach zero, then how is it that light itself can exhibit changes - the oscillation of the E and B fields? Is it because those fields are perpendicular to the direction of light travel? If so, then something other than...

How to calculate time until charged particles (Electron/Positron for example) collide starting at velocity= 0 , distance x apart: Using coulombs law, how do I get the velocity and position equation for a pair of unit charged particles? A simple reference link would be great as I know this is...

if you could leave the planet, and wait a year in space... would you age much much faster than a person on Earth because the Earth was moving relative to you and you are out of Earth's gravity field [like a higher up clock]?

Can the Born rule be understood as time running both forwards and backwards simultaneously? The probability ##P_{i \rightarrow f}## that an initial quantum state ##\psi_i## is measured to be in final quantum state ##\psi_f##, after evolving according to the unitary time-evolution operator...

I have already in a previous task shown that A is not irreducible and not regular, which I think is correct. I don't know if I can use that fact here in some way. I guess one way of solving this problem could be to find all eigenvalues, eigenvectors and diagonalize but that is a lot of work and...

150 km tan(35)=150/x Hyp=316.58 I know this isn't right where did I go wrong or did I even start correctly

The reason why I think it could happen is that spacetime is being curved really extremely in black holes and when you draw a chart of spacetime near and in black hole , you can see that time axis is being bend towards the center of black hole and that thing is happening from all sides of the...

Hi, I've been a full time physics lecturer for three years after the coming spring '21 semester. I got this job at the same university where I graduated with my PhD because (apparently) they liked my TA evaluations from students. Between graduating and becoming a lecturer I spent over a year...

Because the book doesn't have an answer. Can someone confirm if I am correct? The question can be found on page 49 of the link below. I added arrows to the picture just to separate the equations not to say greater then. https://scholar.harvard.edu/files/david-morin/files/relativity_chap_1.pdf...

How would I go about calculating the time taken for the motor on page 2 to move the attached beam 360 degrees? Things such as the rpm and voltage are given in the attached data sheet for various different motors and you can reference anyone you like. I'm more interested in understanding what's...

Hi everyone I'm writing a murder mystery in which someone is poisoned at work at around midnight. The killer wants it to seem like the victim died around 8 am the next morning. They leave the body in a room with the heating running to keep the body warm. Would an autopsy be able to...

When calculating the proper time along a timelike radial geodesic, with the initial condition that object the starts at rest at some Schwarzschild coordinate ##r_0>r_S##, i.e. \frac{\mathrm{d}r}{\mathrm{d}\tau}\Bigg|_{r=r_0}=0\;, after using the equations of motion one finds...

Two quick questions on time dilation and superluminal travel for a situation in which two people are in motion with respect to each other. 1) If Jack is moving with respect to Jill, Jill sees Jack's clock move more slowly relative to her clock, so Jill perceives Jack aging more slowly relative...

I rearranged the displacement formula to d2 = d + d1. I used cosine law to solve for d2 since the triangle is not right-angled but I am not getting the correct answer or angle for d2. The angle I used in cosine law (based on the diagram) was 32+12+90 = 134. d = v(t) = 130(3) = 390 km/h [N 32 E]...

So I figured that to find how long did the ball take to hit the ground I would have to subtract 6 with the time it took the sound to reach back to the player. My givens are Velocity Intial = 330 m/s, speed of sound Δd = 50m Velocity Final = 0m/s because sound stops when it reaches the ear...

This is an experiment on a dilute isotopic mixture of helium gas. A spherical vessel of diameter 1 m is first filled with 4He gas to one atmosphere pressure. Then a small amount of 3He gas is introduced through a valve on one side of the vessel. Make a rough estimate of how long one must wait...

I'm probably am wrong in this but i guess you guys could light me in this one

Let's say you have a leaking tab, and the probability of a droplet in any given second is 1%, regardless of whether there was a drop previously. How would you calculate the probability of n drops in a minute? No drops in a second is 0.99, so no drops over a minute is 0.99^60. Hence one or more...

Hello, I am currently reading "The first Fifteen Lifes of Harry August" from Catherine Webb and really like it so far. I did not even read the half or so but there was an interesting idea I would like to discuss about. As far as I understand Harry August does return after dying to the same...

Let's say, I have a moderate course of Covid-19 in my lungs. I suppose, if I will not be warm and calm, it is possible Covid can change to a worse course and spread more in my body. Is it true? But what can I do extra to avoid spreading in my bode or prevent irreversible damage of my organs if I...

Hello! How was the tau massed measured for the first time? I read that tau was discovered by ##e^+e^-## collisions and they looked for an excess of of end products containing an electron, a muon and some missing energy (coming from the decay the 2 resulting tau's). But the missing energy would...

I take position 1 as the surface of the pool and position 2 as the surface of the container so the value of ##P_1 = P_2 = P_{atm}## and ##v_1=0## and ##h_2=0## ##P_1 + \rho gh_1 + \frac{1}{2} \rho {v_1}^2 = P_2 + \rho gh_2 + \frac{1}{2} \rho {v_2}^2## ##\rho gH = \frac{1}{2} \rho {v_2}^2##...

Hi there. I'm writing a sci-fi story for a video game. At some point in time an advanced civilization from the future, say 4010, creates a wormhole for a not so advanced civilization spacecraft in the past, say 2050, to travel through. The idea is for the not so advanced civilization...

So, the only thing which came to my mind in order to solve this problem was actually to write down the equations using the discharge function, being given two instants and their corresponding charges... but doing so I'm unable to find anything. Ideally, I'd say I should find the time constant...

How would an observer's particle horizon and coformal time be affected by her traveling at very near c (relative to the CMB), both in and opposite the direction of travel (ahead and behind)? Also, how would Hubble expansion be impacted in her frame of reference? (I apologize in advance for...

*Moving this thread from 'General Math Forum' to 'General Relativity Forum' in order to generate more discussion.* Any object will move through spacetime along its geodesic. Since mass bends spacetime, an object initially at rest near the mass will move towards the mass along a geodesic. It...

Before I attempt to delve into the math of tensors and curved spacetime, I'm hoping to get a more general intuitive grasp of things. As such, I'm parsing through a lot of lower level articles on these topics, and several that I've come across have argued that Newtonian gravity can be thought of...

The object moves solely on the $x$-axis, hence I calculated its speed to be $v_x = \frac{dx}{dt} = \frac{c \kappa t}{\sqrt(1+\kappa ^{2} t^2$ Because its speed is not constant, I suppose the Lorentz factor $\gamma = \gamma (t)$, and by plugging in the velocity, I obtain $\gamma = \sqrt(1+ \kappa...

What I have tried is a completing square in the Hamiltonian so that $$\hat{H} = \frac{\hat{p}^2}{2} + \frac{(\hat{q}+\alpha(t))^2}{2} - \frac{(\alpha(t))^2}{2}$$ I treat ##t## is just a parameter and then I can construct the eigenfunctions and the energy eigenvalues by just referring to a...

At time t = 0, the mass of the cart is ##M_0## and velocity is ##v_0## in a time interval ##dt## let a mass of ##dm## be added to the cart due to the pouring water and let the reduction in speed be ##dv## ##\lambda = dm/dt## applying conservation of momentum from the ground frame gives $$M_0...

Disclaimer: I'm not actually sure which acceleration is proper and which is coordinate, and I can't recall the source for the half-remembered equation. I spent some time going through my bookmarks, but it was to no avail. Sorry about that. So, general relativity removes the idea of gravity as...

Hello, just some general questions I have been thinking about 1. So as you approach the speed of light time slows down, but why not at everyday speeds like walking around? I know people are going to say time slowing down only matters at extremely high speeds. However, shouldn't time dilation...

I have been able to prove to myself that, based on Einstein's two postulates and the the Pythagorean theorem, that time dilates. From here how do I prove that length contracts? (All of this observing a frame that is moving relative to the proper frame at uniform velocity.)

Hello there.About time dilation, could we provide a derivative of time in relation to one of the coordinates of the manifold we have taking time as a function and get something as a result?Or its integral?And about time dilation we have the formula that gives it between two clocks and an...

Hi, I'd really appreciate it if you could help me with the queries below. I think that the quoted text below at the bottom is a very simplified way of describing what happens when an interrupt happens. I believe that in reality the process would be more complex. The processor needs to store...

As in, is it a physical quantity/parameter like mass or is it a descriptive name that we give to the flow of dynamic processes? This is not a theory or idea, just a question that I feel compelled to ask after reading an article that claims that a study shows that time travel would be possible...

When I learned about Einstein solids in thermal physics, we assumed the fundamental assumption of statistical mechanics. For two interacting Einstein solids, I completely understand why this is valid after a considerable amount of time has passed. But, how can we model these solids as they get...

If on Earth we detect the light from a supernova 100,000 light years away, we can say that the supernova happened 100,000 years ago (ignoring any dust etc. that might slow down the light). However, would all observers agree that the event happened 100,000 years ago? If a spaceship was traveling...