Does light travel indefinitely, or does it dissipate over time?

Light is one of the most intriguing phenomena in the universe, and one of its most remarkable properties is that it travels at a constant speed in a vacuum. However, the question of whether light dissipates over time or not is a bit more complicated than a simple yes or no answer.

First, it's important to understand that light is made up of photons, which are particles that have energy and momentum but no mass. When a photon is emitted, it travels away from its source at the speed of light, but it doesn't necessarily travel indefinitely. Instead, it interacts with the matter and energy around it, which can cause it to be absorbed, scattered, or reflected.

So, while light doesn't necessarily dissipate over time, it can be affected by the environment it travels through. For example, light passing through a gas or liquid can be absorbed by the atoms and molecules in the substance, which can cause the light to lose energy and change direction. This is why the sky appears blue during the day, because the light from the sun is scattered in the atmosphere by tiny particles and molecules.

So, to answer the question, light does not dissipate over time in the sense that it doesn't simply disappear, but it can be affected by its environment and interactions with matter and energy along its path.