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### Are measurements of time and distance independent or always coupled by the speed of light

In texts about special relativity the light clock is usually described as a tool to measure time $t$. It counts how often light travels along a given distance $d$, i.e. $t = d/c$, where $c$ is the ...
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### How were the ratios of distances between planets and the Sun first calculated?

I was reading some literature and I found that long before the actual distances between other planets and Earth or distance between Sun and Earth were known, physicists had calculated the ratios ...
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### Calculating distance between two objects viewed from an angle [closed]

I'm trying to determine the location of this vehicles rear bumper and the front edge of the white road marker. I can't tell if the vehicle is before, at the edge, or just ahead of the marker. The ...
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### Finding acceleration and distance when velocity given

I am trying to do the following question for practice (it is an interview question), and I don't know if my methods and answer are correct. Given a velocity $v=2+3t^2$, find acceleration after 3 ...
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### How the distance and diameter of the stars are experimentally measured?

How to measure the distance of a star and the diameter of it from earth based tools? Normally we can measure the angle between the stars edge. But diameter or distance needed to measure the other ...
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### What is the difference between the actual distance covered by a projected object and the displacement?

What is the difference between the actual distance covered by a projected object and the displacement? A stone was projected with an angle of projection of 30 and it covered a horizontal distance ...
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### Distance as a function of time where acceleration changes with respect to distance

I was thinking the other day about gravity. I know that acceleration in a magnetic field changes with respect to distance from the center of the field. So I was thinking, how would one find the total ...
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### Will an un-scattered photon go to the edge of the universe? [duplicate]

Will an unhindered (un-scattered) photon go to the edge of the universe?
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Assume a wave function $\psi = \psi(x,t)$ where $x$ is position from the starting point $(0,0)$ and $t$ is time. Two oscillating points A and B are located at $x_1$ and $x_2$ respectively with $x_2 \... 2answers 109 views ### Is in this case distance same as displacement? [closed] I have this graph, and I need to know the displacement in the interval from 0 to 5 seconds, so I found the area of the rectangle that you can see there. A = w*h, which means X = (5 seconds)*(20 m/s), ... 1answer 130 views ### Measuring more accurately the distance of remote galaxies From what I read in Wikipedia, the velocity of a Galaxy has two components: one is due to Hubble's law for cosmic expansion, and the other is the peculiar velocity of the galaxy. Since the peculiar ... 2answers 55 views ### Time, distance perception [duplicate] If photons going c have no local time or distance 'perception' why isn't the same true for us as we're going c relative to them? 1answer 753 views ### What distance does one travels in his lifetime? [closed] I think this isn't answerable without having point of reference from which speed at which earth travels in space, however if I am wrong the please give absolute distance. Considering that earth spins ... 2answers 98 views ### Speed of light and distance Our measure of distance (the meter) is defined in terms of how far light in a vacuum travels in a specific time. When light travels through another medium, we say it travels at a different speed. Why ... 1answer 674 views ### Why do we observe opposite motion of trees (nearer) and trees (distant) when seen from a moving frame? [duplicate] If you are in a moving train or in a bus, what you observe is that the trees which are nearer to you move opposite to the direction of your motion. But the trees which are very far away from you, ... 1answer 100 views ### Distance from redshift I am looking for a exact derivation of a relation between redshift$z$and distance$d$. What I know is the definition$$z=\frac{\lambda_{\text{observed}}}{\lambda_{\text{unshifted}}}-1=\sqrt{\frac{1+... 2answers 74 views ### How are the distances to the most distant$\gamma\$-ray bursts measured?

This question came to my mind when I read on NASA's website that an explosion (gamma ray burst, GRB 080913) took place 12.8 billion light years away from us. How do they measure such large distances?