Actually nothing is infinite is an incorrect statement how can nothing be infinite?
Scientifically, nobody knows.
Does the cosmos go on forever, or is outer space finite? Explore this age-old question.
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And time is time, it is the measurement of it that is relative.
No. Time and space are relative, as the only factor that is constant is the speed of light.
Is the speed of light different at different altitudes?
No.
Perhaps extremely different due to atmospheric refraction and such.
The medium through which the light travels can alter the light's trajectory of course, and gravitational pull can bend the light, but nevertheless it still follows its trajectory at a constant speed.
But that is just to get from point a to point be because the light is refracted somewhat and not travelling in a straight line. The speed is the same.
Atoms can also absorb a photon and emit another photon in such a way that there appears to be a brief moment of delay elapsing between the two separate events.
Gravity will have some very slight impact as well but again light is travelling the same speed just a different path so take longer to get from point a to point b.
Gravity in the form of a black hole can have a profound impact, as the light can no longer escape from it after it passes the so-called
event horizon. But yeah, this is due entirely to the relativity of space and time, as the speed of light is still nevertheless constant.