All Questions
17
questions
2
votes
1
answer
161
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When you are in a gravitational field, do object far away get physically closer to you as you get closer to the mass?
An observer A is close to a black hole and an observer B one light year away. They are both remaining at constant radial distance from the black hole. A is at 2 Rs away from the center of the black ...
- 171
0
votes
2
answers
124
views
If we find a star exploding 100 light years away, that means it happened 100 years before? [duplicate]
So can someone please help me with this? Can someone make the answer as simple as possible?
So my question is if we see a star exploding like 100 light-years away, that means that star exploded 100 ...
3
votes
4
answers
677
views
How close should you get to speed of light, in order for time to be dilated?
Recently I was watching Carl Sagan's Cosmos: A Personal Voyage. In episode 8 ("Journeys in Space and Time") there is a scene presenting the idea of time dilation, due to traveling close to the speed ...
user187075
0
votes
2
answers
51
views
Why do we locate stars based on the light we see from earth?
Mapping space from our milky-way to Laniakea and the CMB, we always put a star or galaxies position from the light we see in that 3d coordinates of the universe.
But really if a star or galaxy we look ...
2
votes
2
answers
196
views
Is speed essentially infinite for a massless object moving at $c$?
My current understanding of the topic does not allow me to answer this question.
Also, by 'object' I mean a theoretical massless macroscopic object (if we assume such an object is possible, and if ...
- 209
2
votes
1
answer
337
views
Gravity, acceleration and reference frames [closed]
Let’s say the universe was empty and suddenly an astronaut and the sun appeared 2 light years apart. Using the reference frame of the Astronaut, would he be pulled towards the sun as soon as he can ...
- 31
1
vote
0
answers
34
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A point on a disc travelling at the speed of light [duplicate]
This might be a duplicate of this.
I had an interesting thought experiment: suppose that you have a disc of a 1 m radius, where a point P2 inside the disc travels at the speed of light. You have a ...
- 11
0
votes
1
answer
600
views
Does a black hole really slow down time?
When an object gets pulled into a black hole it seems to slow and stop, but could it be possibly be because the speed of light that hit the object and came back was slowing down as the object got ...
- 11
0
votes
4
answers
748
views
Does light in vacuum actually travel at the speed of light? [duplicate]
I know my question sounds like a joke (and I suppose on some level it is) but I'm confounded by the following:
As the thought experiment goes, if I'm in a spaceship flying rapidly the people on earth ...
- 469
0
votes
1
answer
234
views
Coordinate Time and Proper Time/Simultaneity [closed]
At close to the speed of light, clock A is running slower than "stationary" clock B. Does clock A enter the future time reference of clock B as it slows down?
Trying to understand where the forward ...
- 11
4
votes
2
answers
708
views
How do we know the speed of light is constant and spacetime dilates rather than vice versa?
Some conspiracy nut was telling me that Einstein was BS and there's a giant conspiracy that he's wrong but scientists would loose all their jobs if they admitted it. Of course this is all baloney, ...
- 360
1
vote
1
answer
1k
views
Is distance always 0 relative to an object moving at speed of light $c$? [closed]
As I understand it, when an object is traveling at the speed of light, relative to itself all travel is instantaneous and the distance is zero. If a photon traveling from the sun was aligned with the ...
- 119
1
vote
2
answers
212
views
Can a point in empty space be motionless with respect to light?
Being that the speed of light is constant throughout the universe, can a point in empty space be motionless with respect to light?
- 11
3
votes
1
answer
198
views
Can special relativity be extended such that the frame of a photon makes sense?
Suppose I want to know what the universe looks like from the perspective of a frame of reference moving at $c$ relative to my current frame. As discussed at length in various other questions on this ...
- 24.6k
-2
votes
1
answer
234
views
How would time duration and space distance change when we move in the speed of light? [closed]
It is possible to figure out how time duration and space distance change when we are close to the speed of light - but I am not sure what happens to them if we travel in the speed of light.
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