All Questions
18
questions
0
votes
1
answer
67
views
Can we observe a more recent space?
The space we are viewing now is their distant past as their light has only reached our eye or telescope after travelling a long distance at the speed of light. However, for lights that are still on ...
0
votes
1
answer
67
views
Light and Special Relativity
If an object is in motion that means time slows down for the observer in motion. So if there is a planet that is 1 billion light years away that is moving away from us does that mean we are seeing ...
- 61
-1
votes
2
answers
203
views
Why does light move? [closed]
According to Einstein's theory of special relativity, the phenomenon known as time dilation occurs when an object is moving faster than another. The closer to the speed of light this object gets, the ...
- 39
0
votes
3
answers
662
views
Will you see distance contraction inside the space ship at near light speed?
We know that distance to destination contracts for a passenger in a spaceship traveling at near the speed of light. If a spaceship is traveling at 0.865C to the outside observer, then the distance to ...
0
votes
1
answer
45
views
Redshift and speed $c$
If the speed of light in vacuum is constant to every observer then how is the shifting of light color possible?
I am assuming that a single particle of light (a photon?) has the capability to contain ...
-1
votes
1
answer
101
views
Thought experiment: if an observer can travel at the speed of light [closed]
What would the observer see if he could travel at the speed of light and shot a photon beam at the same time?
- 9
3
votes
3
answers
548
views
What exactly does the observer's coordinate system mean in special relativity?
This seems like a very basic question but I'm having a hard time understanding it, more precisely hard time visualizing it. Let say there is an observer, and we wish to somewhat formalize his ...
- 79
-3
votes
2
answers
188
views
If a massless observer is going at the speed of light, what speed will it measure of a light beam going parallel to it? [duplicate]
If a massless observer is going at the speed of light, what speed will it measure of a light beam going parallel to it?
- 159
1
vote
2
answers
146
views
What will the observer observe?
Consider the case where observer $A$ is at rest, and observer $ B$ is moving with speed $\frac{c}{2}$ (where $c$ is the speed of light) propagating a wave with wave speed $c$. So my question is what ...
- 213
-1
votes
2
answers
303
views
Can someone explain Einstein's light clock?
The explanations for time dilation that I have seen all use the thought experiment of a photon bouncing between two parallel mirrors, which are themselves moving in a direction perpendicular to the ...
3
votes
3
answers
527
views
Young and Freedman Proof: No Observer Can Travel at the Speed of Light
I have been reading the section on Relativity in the ninth edition of University Physics by Young and Freedman. They include the following proof that no observer can move at the speed of light.
...
- 33
1
vote
4
answers
328
views
How is it possible for an observer to measure the speed of light as it moves AWAY from him?
I often come across statements such as this one, by N. David Mermin, a well-known physicist:
"Let P be a valid procedure for carrying out the time and distance
measurements that allow one to ...
1
vote
0
answers
81
views
Light at the Speed of Light [duplicate]
Since light particles travel at the speed of light, we know it's possible for something to travel at that speed. However, since all things are relative, and if time does stop at the speed of light, ...
user108794
0
votes
0
answers
68
views
Speed of light, comparison of two light waves travelling side by side
okay so.here is setup of my question...say we have two observers A and A'..A is fixed to origin of coordinate axis x,y while A' is inside a hollow box (shown as rectangle MNRP) whose one side MN has ...
- 57
0
votes
5
answers
761
views
Frames of reference and why are they different
Here is a quote from "The Elegant Universe" by Brian Greene.
Imagine two countries that have been at war are sitting down to sign a treaty ending hostilities while traveling aboard a train ...
- 69