Why Does Light Take 8 Minutes to Reach Earth from the Sun

stavragy
Messages
1
Reaction score
0
Question:
Light experiences zero time and zero distance so for a photon it must be here and there at the same instance. As the moment a photon is created it must be at position A and B at the same moment.
So for a Photon it takes zero time to reach Earth from the sun.
Why do we then see light taking 8 minutes to reach us?
 
Physics news on Phys.org
stavragy said:
So for a Photon it takes zero time to reach Earth from the sun.
This is neither correct nor relevant. See the FAQ: https://www.physicsforums.com/showthread.php?t=511170

stavragy said:
Why do we then see light taking 8 minutes to reach us?
Because the sun is a distance of c*8min away in our frame.
 
stavragy said:
Question:
Light experiences zero time ...Why do we then see light taking 8 minutes to reach us?
We experience 8 minutes, not the light.
 
A.T. said:
stavragy said:
Question:
Light experiences zero time ...Why do we then see light taking 8 minutes to reach us?
We experience 8 minutes, not the light.
What do we experience that takes 8 minutes (aside from the fact that it takes 8 minutes for our clock to tick through 8 minutes)?
 
ghwellsjr said:
What do we experience that takes 8 minutes (aside from the fact that it takes 8 minutes for our clock to tick through 8 minutes)?
The time that light takes to go from the sun to the earth, as measured in our frame of reference, of course. (Which is what the ticking clock measures.) How long it takes light to go from the Earth to the sun in any other frame of reference, including that of light, is not relevant.
 
OK, so this has bugged me for a while about the equivalence principle and the black hole information paradox. If black holes "evaporate" via Hawking radiation, then they cannot exist forever. So, from my external perspective, watching the person fall in, they slow down, freeze, and redshift to "nothing," but never cross the event horizon. Does the equivalence principle say my perspective is valid? If it does, is it possible that that person really never crossed the event horizon? The...
ASSUMPTIONS 1. Two identical clocks A and B in the same inertial frame are stationary relative to each other a fixed distance L apart. Time passes at the same rate for both. 2. Both clocks are able to send/receive light signals and to write/read the send/receive times into signals. 3. The speed of light is anisotropic. METHOD 1. At time t[A1] and time t[B1], clock A sends a light signal to clock B. The clock B time is unknown to A. 2. Clock B receives the signal from A at time t[B2] and...
From $$0 = \delta(g^{\alpha\mu}g_{\mu\nu}) = g^{\alpha\mu} \delta g_{\mu\nu} + g_{\mu\nu} \delta g^{\alpha\mu}$$ we have $$g^{\alpha\mu} \delta g_{\mu\nu} = -g_{\mu\nu} \delta g^{\alpha\mu} \,\, . $$ Multiply both sides by ##g_{\alpha\beta}## to get $$\delta g_{\beta\nu} = -g_{\alpha\beta} g_{\mu\nu} \delta g^{\alpha\mu} \qquad(*)$$ (This is Dirac's eq. (26.9) in "GTR".) On the other hand, the variation ##\delta g^{\alpha\mu} = \bar{g}^{\alpha\mu} - g^{\alpha\mu}## should be a tensor...
Back
Top