Transparent. It lets light go through and so you can see through it to.
Also, the word Diaphanous can be used.
Definition: to allow light to pass through; delicate
I think the word you're looking for is "refraction."
The word is rainbow. Rainbows occur when light is reflected inside droplets of water and then refracted out into the air.
The noun form of the word "transparent" is "transparentness." Transparentness can be defined as the state of transmitting light rays through its substance.
The answer is right there in your question. "Light year" is the distance that light travels through space in one year. In one year of time, light travels one light-year of distance through space. In 46 years of time, light travels 46 light-years of distance through space. It takes 364 years of time for light to travel 364 light-years of distance through space. Now, to return to your question: For light to travel 600 light-years of distance through space, that would take 600 years of time.
It is a Greek word. It is made up of the words φως (phos, meaning light) and σύνθεσις (synthesis, meaning putting things together in order to make something). Therefore the meaning is "using light to make something" (energy to grow, etc) Save
The word for how far something travels is distance.
The word is "light-year".
Transparency.
Opaque
another word for fast is speed
In general, an aperture is a hole through which light travels. In relation to photography, where the word is most commonly seen, this denotes the size of the hole through which light travels to hit the camera's sensor. Longer exposures need smaller apertures to ensure that the picture is not overexposed, and shorter exposures need a larger aperture to get enough light.
lasers
Scientists use the term "refraction" to describe the bending of light as it passes through different mediums, such as air, water, or glass. This bending occurs due to the change in the speed of light as it travels through substances with varying densities.
The word for something that gives out light without heat is "luminescent." The process is called luminescence, and the light produced is often referred to as "cold light."
The word for materials that do not allow light to pass through is "opaque." This means that the material is not transparent or translucent, resulting in the obstruction of light passing through it.
The word you are looking for is "luminary".
"Translucent" means letting some of the light through. It does not mean anything about how much would be too much, though.