The distance that a beam of visible light can travel before being absorbed by something depends on various factors, including the composition of the medium it passes through and the wavelength of the light itself.
In a vacuum, where there is no matter to absorb or scatter the light, visible light can theoretically travel an extremely long distance without being absorbed. However, in reality, there are very few situations where light encounters a complete vacuum.
When light passes through a medium such as air, water, or glass, it interacts with the atoms or molecules in that medium. Some materials are more transparent to visible light than others. For example, air is relatively transparent to visible light, so light can travel long distances through it before being absorbed. In comparison, materials like dense metals or opaque liquids can absorb light more readily.
The absorption of light also depends on the specific wavelength or color of the light. Different materials have different absorption characteristics for different wavelengths. For example, certain dyes or pigments may selectively absorb certain colors of light while transmitting others.
In general, in Earth's atmosphere, light can travel significant distances before being absorbed. However, if the light passes through dense materials or encounters substances that strongly interact with its specific wavelength, the distance it can travel before being absorbed may be relatively short.
It's worth noting that technological advancements in fiber optics have enabled the transmission of light over long distances with minimal absorption or loss. Fiber optic cables use total internal reflection to guide light pulses, allowing them to travel for thousands of kilometers before the signal requires amplification.