is there a limit to how far light can travel?

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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

11 Answers

Anonymous 0 Comments

When distant stars seem dimmer it’s not because their light is getting “degraded” on the way, just that less of it is reaching us because it is spread over a greater area.

Light can theoretically travel indefinitely in a vacuum. Practically it can (and does) run into stuff on the way, like interstellar dust and gas. But to answer your question no, there is no limit to how far light can travel.

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