Looking at stars yesterday set me to thinking if there was such a thing as a maximum distance that light can travel…?
Clearly stars are less bright than our sun and this must be a function of their distance from us (and also their initial brightness). But these distances are absolutely, mind-bendingly huge: we can see stars thats are hundreds of millions of light years away. And they are still visible not only after huge distances but also massive amount of time.
So is light not subject to “decay” or some form of “resistance” to travel that would mean there is a limit to how far (length) or how long (time) it could travel before it becomes completely unseen?
I realise I am using analogies that would be more relevant to sound or waves in a liquid so it may just be my incomprehension of the “light” phenomena and how it works that means ive missed the point… 😀
In: Physics
The decay is called redshift and it happens because of the universe expanding relatively faster the farther away it is. This isn’t the reason we can’t see forever though. The reason we can’t isn’t because of redshift but because at a certain distance the universe is expanding away from us at past the speed of light so light from those stars will never reach us.
It’s called the Hubble Sphere.
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