# What happens after the light from the sun has travelled its entirety? [duplicate]

The light from the sun will stop traveling after a particular distance due to its intensity becoming 0.

Up to which planet does the light from the sun travel before which it dissipates into nothing?

If light ceases to exist after a particular distance, How are we able to use telescopes to see objects further than that?

By objects I mean the objects like planets or other bodies that don't emit light on its own.

I'm sorry if my question is trivial, I'm not a physics grad or anything.

Thanks.

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• Fortunately, the light from the Sun doe not stop traveling before it reaches the Earth. Otherwise the Earth would be a very dark and cold place... Oh, alright, seriously, light never stops traveling :) – safesphere Nov 10 '17 at 7:31
• @safesphere How can that be? After its energy becomes 0, the light has to stop, isn't it? – Bej Nov 10 '17 at 7:32
• It never disappears. Light consists of photons, which just keep going forever. The Cosmic Microwave Background that we detect in the sky was the light emitted about 13 and a half billion years ago that accordingly has traveled to us over the distance of 13 and a half billion light years and still going. It does get weaker and loses energy, but there is no limit to it (until you get to single photons). – safesphere Nov 10 '17 at 7:36
• @safesphere MINDBLOWN. Thanks for the response, Put it as an answer so I can select it correct answer. – Bej Nov 10 '17 at 7:38
• It takes no energy to travel at a constant velocity through flat spacetime. That applies to light as well as to things made of matter. So when light travels through flat spacetime it doesn't use up any of its energy. However, it does spread out, in accordance with the inverse square law, so the intensity of the light per unit area diminishes. – PM 2Ring Nov 16 '17 at 6:30