# What is Time delay: Definition and 44 Discussions

The Shapiro time delay effect, or gravitational time delay effect, is one of the four classic solar-system tests of general relativity. Radar signals passing near a massive object take slightly longer to travel to a target and longer to return than they would if the mass of the object were not present. The time delay is caused by spacetime dilation, which increases the time it takes light to travel a given distance from the perspective of an outside observer. In a 1964 article entitled Fourth Test of General Relativity, astrophysicist Irwin Shapiro wrote:

Because, according to the general theory, the speed of a light wave depends on the strength of the gravitational potential along its path, these time delays should thereby be increased by almost 2×10−4 sec when the radar pulses pass near the sun. Such a change, equivalent to 60 km in distance, could now be measured over the required path length to within about 5 to 10% with presently obtainable equipment.

Throughout this article discussing the time delay, Shapiro uses c as the speed of light and calculates the time delay of the passage of light waves or rays over finite coordinate distance according to a Schwarzschild solution to the Einstein field equations.

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1. ### Different sunset times due to elevation ##h## at a point on the Earth

Problem Statement : I draw a picture of the given problem alongside. P is the location of the man and Q that of his friend at a height ##h## above. If the sun is at a position ##\text{S}_1## at 6 pm, at what time is the sun at position ##\text{S}_2##? Attempt : If ##\text{S}_2Q## is inclined to...
2. ### Mechanical device trigger with variable time delay (100-500ms)

This device, if it or something similar exists at all, needs to be completely mechanical without ANY electricity and be really precise and strong (to last a long time). Press a button in order to trigger the start of the delay time. It must start only when the button is fully pressed down (or...
3. ### I Time Delay Information Transfer with Entangled Particles

Hello, my name is Jack and I'm a year 11 student in Australia. After listening to, and reading some information regarding quantum entanglement, I'm still a little unsure about the solution to a thought experiment: Let's say that I create a situation in which multiple pairs of particles are...
4. ### I Time Delay on Multiple Photons when travelling from one plac

I'm trying to understand the time delay induced on each photon when several individual photons travel in an open space from a sender to a receiver for example in the application of Quantum Key Distribution. So what I understand so far is light(photon) travel around 299,792 km (186,282 miles) per...
5. ### Make a very simple mechanical time delay?

Hey everyone, I need to make or design a simple mechanical time delay. This probably isn't easy since I can't find anything on the market that's small and cheap. Was thinking some wind up toy might work, haven't found the right one yet. I was thinking maybe small box with a rod coming out of...
6. ### Time Delay Margin: Good Large or Small?

I have a question regarding the time delay margin. I know the definition of time delay margin now I want to know that for the stability of the system is it good to have large time delay margin or small time delay margin?
7. ### How to calculate Time Delay Estimation?

I have 2 data files, which links are attached below: Transmitted data https://www.dropbox.com/s/0nmhw6mpgh7upmv/TX.dat?dl=0 Received data https://www.dropbox.com/s/xgyo6le3bcmd25r/RX.dat?dl=0 Those binary data are read by this MATLAB code: %% initial values: nsamps = inf; nstart = 0; %% input...
8. ### Understanding time delay estimation for GPS?

I really need help to understand these questions which is highlight, for the GPS situation, I hope anyone who has been working in this situation before, please help me to have a clear understanding about "time delay estimation": Here is the scenario: 1. Suppose I know precisely I have transmit...
9. ### Photoelectric effect and zero time delay

How does the zero time delay between illumination of light and emission of photo electron provides an evidence for the particle nature of light?
10. ### How to calculate the time delay based on a function of antenna angle?

Hi everyone, I am a new student who is studying on collecting data from TV signal. I hope everyone can help me for ideas. I am having spectrum analyzer which can define a TV station around me, so I chose 4 stations WHUT-TV [584MHz 590MHz], WPXN-TV [590MHz 596MHz], WTTG [60 MHz 608MHz], and WNVC...
11. ### Magnetic fields and currents - question about time delay

Suppose there is a solenoid near an accelerating electron. The electron must create a changing magnetic field. By Lenz's law, an emf is induced in the coil. One question is, how *fast* is the emf induced in the coil? Is the emf just there instantaneously or does it take time to formulate? And...
12. ### How can i calculate the time delay in arduino?

hi every one , I'm a student in university , i have a projet it's about calculate speed of waves in liquid by to piezo electrique , one workd like emmeter and the other receppter , the distance betwin the two piezo is fixe , the probleme is i nedd to calculat the time betwin the moment who i...
13. ### Deriving the Shapiro time delay

Homework Statement The step I am trying to follow is detailed here where I am trying to get from equation 6.26: t=\int_{r_1}^{r}(1+\frac{2M}{r}+\frac{b^2V(r)}{2}+\frac{Mb^2V(r)}{r})dr to equation 6.30 t=\sqrt{r^2-r_1^2}+2Mln(\frac{r+\sqrt{r^2-r_1^2}}{r_1})+M(\frac{r-r_1}{r+r_1})^{1/2} Homework...
14. ### Help me design a simple time delay (not electrical)

Hey everyone I'm trying to design a simple time delayed device. Device could me mechanical but it doesn't really have to be as long as it does what I want. Just need something that is relatively small could be wide and tall just not thicker then 1 inch. The device should have a arm/button...
15. ### How Long Is the Delay for a Signal Traveling via Two Geostationary Satellites?

Homework Statement Question: If a broadcast of a sporting event went up to a geostationary satellite, then traveled 50 000 km to another geostationary satellite, then came back to earth, what would be the delay in the signal? All electromagnetic waves travel at the speed of light, and most of...
16. ### Wiener-Khinchin theorem and time delay

Hi all, I'm working on Brown and Twiss experiment (photon bunching) and I somehow confused by Wiener-Khinchin theorem. I have a laser (green) light which hits the rotating ground glass diffuser to produce a pseudo thermal light. This light is then illuminates a small pinhole (diameter d) and...
17. ### Why the Shapiro delay is calculated with respect to the....?

Why the Shapiro time delay is calculated with respect to the difference in coordinates and not with respect to the physical distance? I follow the discussion of Clifford (Theory and Experiment in Gravitational Physics) which uses isotropic coordinates and PPN approximation. To make more clear my...
18. ### Does impedance affect time delay in digital circuits?

I recently attended a seminar, which said impedance increases with temperature, which results in timing delays in digital circuits. I don't understand how increase in impedance results in delay.
19. ### Calculating Time Delay for Radio Telescope Pointing

Homework Statement A radio telescope, whose two antennas are separated by 55 m, is designed to receive 3.0-MHz radio waves produced by astronomical objects. The received radio waves create 3.0-MHz electronic signals in the telescope's left and right antennas. These signals then travel by...
20. ### Speed of waves and time delay question

Homework Statement [/B] What is the time delay for a television signal that is sent via satellite? Communications satellites orbit above the equator in circles of radius 36,000 km (6 times larger than Earth’s radius!). Not sure if my answer is correct... Homework Equations...
21. ### Time Delay Chart: Understanding Circuit Diagram and Output Hazards

Hello, can someone please tell me how to draw this time chart? I got this from a friend and I don't understand how he got it. A, B, C emit hazard at output Y. Here are the circuit diagram and the time delay my friend drew.
22. ### Discrete Control System with Time Delay

Hello, I am trying to develop a software control algorithm to compensate for oscillator imperfections/frequency drift. I have a NTP server which I can get a pretty good estimation (@1Hz) of the "true" time and compare it to my system's time. I can differentiate the offset-error to calculate...
23. ### Can HMMs accommodate variable time delays in observations?

Hello All, I'm building a HMM for some data where there are two different time delays. Specifically, I collect data in consecutive traces, such that the time delay between each data point within a trace is approximately fixed, and the time delay between each trace is approximately fixed, but...
24. ### How does GPS receiver calculate time delay?

The GPS satellite has an atomic clock which sychronizes with the receiver. But when the receiver gets the time, it is delayed as it travelled. So when its 08h 00min 05s in the satellite, the receiver gets maybe 08h 00min 03s. The time of travel of the signal is 2s but how will the receiver...
25. ### Measuring time delay before charged plates repel

Imagine two parallel conducting plates set at a distance of several meters. If one charges the two plates simultaneously then one would expect a small delay before they started repelling each other due to the time it takes changes in the static field to propagate from one plate to the other...
26. ### Time delay for Persistant HTTP

Hello all. I am trying to understand number 2c of this pdf...
27. ### Engineering Set time delay for a comparator Op-amp circuit

Homework Statement [See attached diagram] I'm trying to design a circuit that connects to the input terminals of the noninverting input of this comparator circuit such that: -The input to my circuit consists of a SPST switch and a 9 volt battery -When the switch is thrown on, there would be a...
28. ### Is the Shapiro time delay effect accepted in science ?

If it is : I would love someone to explain to me how it affect the redshift of galaxies. If it is not : I will toss it in the pseudoscience box and not think about it again Thank you Guacamolewarrior
29. ### Rate related problem with irregular cone and and time delay

A water glass (10 cm diameter at the top, 6 cm diameter at the bottom, 20 cm in height) is being filled at a rate of 50 cm^3/min. Find the rate of change of the height of the water after 5 seconds. V=1/3(3.14) r^2h I'm a little unsure how to approach this problem for two reasons. A) The glass...
30. ### Getting the hubble constant from time delay in a gravitational lens

Homework Statement I am working on a project for my cosmology course. I need to determine the Hubble constant from time delay in a gravitational lens. We are using QSO 0957+561 for our data. My question is how do I determine the relevant distances Dl, Ds? I have Dls already. The...
31. ### Getting the hubble constant from time delay in a gravitational lens

Hi everyone, First time posting, sorry if this is in the wrong format or wrong place. For a project in a cosmology course I need to find the Hubble constant from from time delay in a gravitational lens. the one we are using is QSO 0957+561. My question is how to I find the time delay from...
32. ### Dayton 2A562 Time Delay Relay: 3-60 Secs On/Off?

Can someone please tell about the Dayton 2A562 Time Delay Relay. Does it wait 3 to 60 seconds before powering on, or does it wait 3 to 60 and then power off? I am looking for something that will run for 3 to 60 seconds and then shut off. thanks
33. ### Time Delay Relay: What is a D-O-D Timer & Glow Plug Timer?

What is a Delay-On-Dropout-Timer relay. Is this what can be used for a glow plug timer?
34. ### Experimenting with Shapiro Time Delay Effect

Here is an excerpt from Wikipedia The Shapiro time delay effect, or gravitational time delay effect, is one of the four classic solar system tests of general relativity. Radar signals passing near a massive object take slightly longer to travel to a target and longer to return (as measured by...
35. ### Time delay of speech to travel from moon to earth

So if I'm on the moon is there a delay with the communication to earth? What is the speed of sound over satellites verses copper wires? Anyone know?, this has been on my mind. thanks
36. ### How can I expand the time delay of neutrinos as a Taylor series?

Homework Statement http://img517.imageshack.us/img517/8112/neutrinosll8.jpg Homework Equations The Attempt at a Solution I was able to express the time delay as D(1-\frac{1}{1-\delta}). However, I don't have a lot of experience using Taylor series and did not use one to obtain...
37. ### Time delay for evanescent wave to spread (photon tunnelling)

Nimtz and Stahlhofen claim that their recent tunnelling experiment proves that tunnelling time for light between double prisms is zero. In Herbert Winful's response to this (http://arxiv.org/ftp/arxiv/papers/0709/0709.2736.pdf) he explains that the evanescent wave formed in the gap only has real...
38. ### Producing a Time Delay of 44 Seconds with a 555 Timer

Hi, everyone. I am currently involved in a small electronics project and I am required to produce a time delay for part of the project. I plan on using the famous 555 timer and not quite sure on what to do to produce this delay.So please anyone help explain how to produce a time delay of,say...
39. ### What Causes the Shapiro Time Delay in Radar Signals?

Can someone clear up what is observed in Shapiro time delay experiments. As I understand it a delay is seen in the round trip signal time of a radar signal sent to a distant planet on the opposite side of the sun due to gravitational effects. The signal path would be longer than the straight...
40. ### How to Implement a Constant Time Delay in x86 Assembly?

I need to write a program that will create a constant time delay in x86 assembly, can anybody help?
41. ### Time delay problem for project

Hey, I'm busy doing a project where we have to make the blackjack game. Now my problem is the time delay when they are dealing out the cards. As when we run the game, and click deal we see that both house and player have the cards already. Tried creatin my own delay with for loop, or using...
42. ### C/C++ Time Delay in C++: A Simple Solution for a Few Seconds Delay

Hello. I'm wondering how to make a time delay of a few seconds using C++. The simplest way that came up to my mind is just to make loop for a few millions time or so, but the delay would change from computer to computer.
43. ### Sound Waves - phase difference from time delay

For some reason I have trouble with questions like this. How would I get the phase difference if I were given the time delay of two loudspeakers side by side? I'll use this question as an example: "The speakers are now placed side by side. If the wire to speaker 1 is passed through a...
44. ### Solve Time Delay Equations: Derive (6) and (7) from Mackey-Glass

i need to solve an equation of the form (5) from this webpage http://chaos.phy.ohiou.edu/~thomas/chaos/mackey-glass.html first it asks to "derive the corresponding eigenvalue equation"- i presume they mean to derive (6)? if so, i don't know how they get it. and then they ask for something...