Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to compare the duration of events or the intervals between them, and to quantify rates of change of quantities in material reality or in the conscious experience. Time is often referred to as a fourth dimension, along with three spatial dimensions.Time has long been an important subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars.
Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems.Time in physics is operationally defined as "what a clock reads".The physical nature of time is addressed by general relativity with respect to events in space-time. Examples of events are the collision of two particles, the explosion of a supernova, or the arrival of a rocket ship. Every event can be assigned four numbers representing its time and position (the event's coordinates). However, the numerical values are different for different observers. In general relativity, the question of what time it is now only has meaning relative to a particular observer. Distance and time are intimately related and the time required for light to travel a specific distance is the same for all observers, as first publicly demonstrated by Michelson and Morley. General relativity does not address the nature of time for extremely small intervals where quantum mechanics holds. At this time, there is no generally accepted theory of quantum general relativity. Time is one of the seven fundamental physical quantities in both the International System of Units (SI) and International System of Quantities. The SI base unit of time is the second. Time is used to define other quantities – such as velocity – so defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. To describe observations of an event, a location (position in space) and time are typically noted.
The operational definition of time does not address what the fundamental nature of it is. It does not address why events can happen forward and backward in space, whereas events only happen in the forward progress of time. Investigations into the relationship between space and time led physicists to define the spacetime continuum. General relativity is the primary framework for understanding how spacetime works. Through advances in both theoretical and experimental investigations of space-time, it has been shown that time can be distorted and dilated, particularly at the edges of black holes.
Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined by measuring the electronic transition frequency of caesium atoms (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.
There are many systems for determining what time it is, including the Global Positioning System, other satellite systems, Coordinated Universal Time and mean solar time. In general, the numbers obtained from different time systems differ from one another.
The current definition of Gravity is: The force of attraction between bodies as a result of their mass.
Gravity affects both the space and time of the area surrounding a mass, diminishing with distance, so is the current accepted definition truly accurate? Do I have the correct definition and if...
Homework Statement
Homework Equations
v = d/t
Solve for t. t = d/v
The Attempt at a Solution
In my General Physics 2 course we are doing sound waves I have the answer to the problem which is 90.8m I am trying to understand the concepts of sound wave. So please correct me if I am wrong,
1...
In Griffiths,Quantum Mechanics 2nd edition,Chapter 2,he gives a problem to calculate the revival time of a wave. Revival time is defined as the time taken by a wave to go from one side(x=0) to other side(x=a). Now let's calculate the revival time with 2 methods.
Method 1:
Now to go from 1...
Hello! This is probably a silly question, but I am still confused about it and I really don't have any experience with experimental physics. So I understand that a trigger system has a deadtime, which is defined as the time after which the trigger makes its choice, in which no new events can be...
(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...
I am looking for a book recommendation. I've been looking for something like this on Amazon without success. I want a book on Time Series analysis that includes the following topics: ARMA/ARIMA, ARCH/GARCH, LSTM and deep learning, filters, state spaces, and any other main categories of...
Consider an electron for which l=0 is kept in a uniform magnetic field B.
For which the hamiltonian matrix is {μBB,0,0,-μBB}
now if the electron is in the state 1/√2{1,1}(e.g in the eigenstates of Sx eigenvalue ħ/2}
If this state is time evolved
1/√2{1,0}exp(-iEt/ħ)+1/√2{0,1}exp(iEt/ħ)
where...
So I know gravity correlates with time dilation. If you have two individual equal size black holes close to each other, then at a point between them, gravity is equal to zero. Would the time dilation at that point be a sum of each individual black holes gravity or would the two time dilation...
Let's say I have a client that asks for a file from a remote server that then asks for the file from some other remote server (Let's say Azure Blob Storage, for example). Let's say that the file can be transferred from blob storage to the web server at 60mb/s and from the web server to the...
Hello learned people,
I've been looking at special relativity of muons formed in the upper atmosphere...
If I can summarise what I do understand (i think)...
A muon has 12km to travel to the Earth from the atmosphere at 0.994c. Alice records this as taking 40.2 micro seconds.
Now a muon has a...
When people say that time measured from the Earth is equal to time measured from the Sun minus approx 8 min, are they taking into account Lorentz transformations or simply the fact that light takes approx 8 min from Sun to Earth?
I will use 3 way power splitter and power detector.
1. This is power splitter data sheet. In this data sheet, there are different isolation values. What does it mean?? Also in that point, I wonder definition of isolation at power splitter.
2. This is power detector data sheet. In this data...
Hello to everyone,
I'm trying to find some data about the relation between galaxy age and rotational curve... until now without success.
Are there any teams working on this? Are there any studies in this direction?
Thanks!
Folks, I'm back to reading Muller's paper (https://arxiv.org/pdf/1606.07975.pdf) about the flow of time. He postulates that time is expanding similar the way space is expanding (ok... so if you can swallow that). He asks: "why are the new nows created at the end of time, rather than uniformly...
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...
Homework Statement : [/B]
Find the time constant of an inverting op amp with C = 50uF, Ri = 200 Ohms, Rf = 20 Ohms.
This is a problem I have found in a prep book for the Fundamentals of Engineering Exam (Electrical component). The book gives the answer as time constant = Rf * C. I am not...
Hello everybody, I've just started studying special relativity and seem to be having a bit of a problem with understanding the concept of proper time.
In Modern Physics, by Serway, proper time is defined as the time interval between two events as measured by an observer that sees both events...
I'm armchair knowledgeable about GR, but I've come up against something I can't eloquently explain (to someone who asserts otherwise and wants an unassailable answer).
What property results in time dilation even when net gravity is zero?The net gravity at the centre of the Earth is zero, but...
Is anyone did experiment on diffraction with single particle at a time? Do they get diffraction pattern? I referred particle as both electron and photon
And I want to know any experiment( classical, or single particle at time) don't show any diffraction pattern in single slit experiment.
It seems that the entanglement of two particles does not change with time and can cross long distanced as long an neither particle decoheres with the environment. This makes me wonder if the wave function for that entanglement can have any time or space dependence? I only did a brief search for...
A moving particle has been at position X for zero time. Was it ever at position X?
Can zero time be considered as never, as in "I was in Rome for zero amount of time."?
It seems like it would have been at position X if time passed in pieces the size of Plank time.
This is only something I’ve noticed, and in my eyes it’s odd, it may be utterly wrong or already well known but with some fancy term that I don’t know.
Suppose an object- say, a clock- is moving towards you, at about .5c. For the moment, we will assume time dilation is negligible, and that you...
Hello all.
I was playing around with the time dilation equation : √(1-v2/c2)
Specifically, I decided to take the derivative(d/dv) of the equation. Following the rules of calculus, as little of them as I know, I got this:
d/dv(√(1-v2/c2) = v / (c2√(1-v2/c2)).
Now, this seems reasonable enough...
Hello!
Einstein's theorem is in the last sentence of the following quote (bold) [1]:
"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...
Homework Statement
Question 6.
Homework Equations
Time constant = RC
The Attempt at a Solution
I think answer should be 1/2 RC as Rnet = 1/2R and to convert it to single resistance form we should first find Rnet
But the answer is coming out to be RC . How?
<< Corrected Image added by...
Homework Statement
I am currently stuck on a problem as shown below. My confusion really come from the fact that I can never seem to understand the difference between proper time and time dilation. As in some books they seem to mean the same thing and never give a clear indication
Homework...
When we approach a black hole, the effect of gravity is such that relative to us, time far from the black hole would approach infinity as the distance to the Event Horizon approaches zero. But what happens when we cross the Horizon? How do we measure time outside? Will infinite time have have...
This has been bothering me for some time, and would like to get a physicist's view of it.
If my understanding or contention is in error, please correct me (gently). I only have under grad
physics from 1970, and was a microbiologist, though am interested in quantum physics, cosmology.
My...
Out of my own curiosity I've looked at questions that physics can't answer yet, and this one "How does time move forward?" Seemed to be the most interesting to me. Any Theories?
I have stumbled upon this article, which sounds a bit too fantastic to me. For one, because I can't imagine others haven't tried this before, and secondly: Will there be any chance to link this with actual observations which are suited to distinguish these solutions from more common ones...
Let's say you have an impulse of noise, eg. via a guitar string, or a resonant bandpass filter, and it decays naturally. If "1" is the maximum initial amplitude of sound, and "0" is no sound at all, what is the equation for decay of sound over time (x)?
Is it:
y = 1/c^x
Or y = 1/(x+1)^c
I...
Hello everyone,
By considering the effects of the gravitational time dilation the speed of the inner stars must be higher for the local observer than for the external one. So why the gravitational time dilation can not potentially explain the galaxy rotation curve? I already read that the...
Hello,
I recently bought a Dyson vacuum and have been excitedly vacuuming my floors way more than I need to! I have been doing some thinking as well on the matter (yes, vacuuming) and have a physics problem/question. It has been a long time since I studied physics, so I am not equipped to...
What is the time complexity for an OS to find a file? Is it O(1) time?
Let's say for example, you had a billion files in a single folder, and you wanted to load a file into a string in your program, would the system find a specific file right away, or would there be a longer wait?
Let's...
At the suggestion of some of the members here, I am reading the book Space-Time Physics by Wheeler. The last problem in the first chapter states:
"In a given sample of mesons, half will decay in 18 nanoseconds (18 x 10-9)), measured in a reference frame in which the mesons are at rest. Half of...
Hello
My name is Joseph I am a physics student, I am new to Fortran, I know how to write a code for solving differential equations, but now I have a physics equation for evolving star rotation as a function of mass. and I do not know how to evolve (using any numerical method, such as Euler) so...
To date, the most accurate verification of the time effect of gravity is where two satellites were accidentally put into elliptical orbits where the altitude varied by 8,500 kilometers ( 5,282 mi). Their atomic clocks ran slower near Earth and faster at higher altitude. The agreement with GR was...
Homework Statement
In a short time dt, the probability that a car passes an observer is dt/τ. In a random time interval of length T, what is the probability P(n) that exactly n cars pass the observer?
The Attempt at a Solution
I can only see how to find P(0) the probability that no cars pass...
So, I am confused about the following.I learned in high school and in my first year of university that there is something called time dilation that observers observe that time is slower for objects that are moving faster. As in if there were two initially synchronized clocks that you could...
The theory regarding two persons experiencing different amounts of time dilation due to the two persons being influenced by different amounts of gravity states that while one person stays on Earth under its gravity and another person travels through space under less influence of gravity (less...
For this problem at t=0
Ψ(x,0)=Ψ1-Ψ3
Where Ψ1 and Ψ3are the normalised eigenstates corresponding to energy level 1 and 3 of the infinite square well potential.
Now for it's time evolution it will be Ψ1exp(-iE1t/ħ)- Ψ3exp(-iE3t/ħ)
And taking the time given in the question the time part of the...
Homework Statement
Homework Equations
For this question my ans. is coming option (3) since the time part of the wave comes out to be same for both the energy states which is (-1)^(-1/8) and (-1)^(-9/8) respectively (using exp(-iEt/ħ)).
But the correct option is given option (4).
Am I right...
Is time its own dimension or is it a constant that remains through all dimensions? Also, are there multiple dimensions of time, and how do we know the answers to these questions?
Is it possible to estimate the gravitational force of the center of a Galaxy (it could be Andromeda or the Milky way) to any point (such as a planet) of its Orbit? Furthermore is there such as Schwarzschild solution that calculates the time dilation of any point of an external Galaxy (e.g...
Homework Statement
Homework Equations
Z = √(XC2 + XL2)
XL = 2πƒL
XC = 1 / 2πƒC
I = V/Z
The Attempt at a Solution
First off, thank you for all of the help this semester. I'm sure you'll be seeing questions from me in the spring also. Here is how I'm thinking about this problem:
1. Using the...
My background is that I'm an applied mathematician and engineer, self-taught in GR and QFT. It's an old idea, in some dozen or so SciFi books. But I'm looking for a mathematical framework for handling it. The second law of thermodynamics, that entropy always increases in a closed system, can be...
Homework Statement
Suppose the potential in a problem of one degree of freedom is linearly dependent upon time such that
$$H = \frac{p^2}{2m} - mAtx $$ where A is a constant. Solve the dynamical problem by means of Hamilton's principal function under the initial conditions t = 0, x = 0, ##p =...