If lights is extremely fast and manages to get to the Sun to the Earth without getting darker. How come light can’t bounce off everything and manage to get into every crevice of Earth. Why are there shadows and why do they vary in shade? They should logically be the same shade right?
In: Physics
Think of light as the seven dwarfs, running in a straight/wave pattern. When they bounce off things goblins snatch up some of these dwarves. Depending on which ones are snatched up depends on the resulting colour.
The reason reason why shadows exist is because they are racing on an invisible course and this course is straight. Running from the source to a surface directly in front of it, at which point the goblins snatch up the dwarves. Now you may ask what happens with mirrors, mirrors are very shiny and as you know goblins like dark environments, so goblins can’t exist in mirrors and therefore no dwarves are snatched up and they all bounce off.
It also gets absorbed. For example if an object is green it absorbs all light except green light. The green light bounces off of it.
The sun produces a TON of light, but it does become less dense by the time it gets to Earth.
When the light gets to Earth, it hits whatever’s in its path and then scatters in tons of directions. Most of it reflects back off into the sky, but some bounces sideways a bit onto other surfaces. This little bit isn’t as bright, so it can’t fully illuminate the shadows where the sun’s light didn’t originally hit, but it can light it up a little which changes the shade. This light will eventually bounce away into the sky again too.
Because nothing reflects 100% of the light that hits it. Everything absorbs *some* amount of light, and that light gets scattered in every direction, meaning the next thing it hits is not as bright because there is less light hitting it *and it* absorbs some of it, and so on.
It’s a matter of HOW MUCH light reflects, and on what wavelengths in what amount.
Within the visible spectrum of light, different wavelengths of light appear to your eyes as different colors. Different materials will absorb or reflect more or less light on different wavelengths.
Take a lightbulb and shine it at an incredibly green wall. The pigment of the paint reflects a great deal of light in the wavelength of 534–545 nm, and a lot less outside of that wavelength (but still in the visible spectrum) absorbing it instead. What happens when you put your hand in front of the light? A shadow occurs. Why? Photons that normally would go directly from the lightbulb, reflect off the wall, and hit your eyes again are being blocked by your hand, which means a lot less light in that specific section of the wall is reflecting back at your eyes. So it would still be a green shade, just a lot darker.
If you thought about your question a bit, why isn’t the moon as bright as the sun since it is reflecting the sun’s light?
Therefore somewhere your reasoning must be incorrect. Also if every object reflected ALL the light that hit it, then everything on earth you see should be as bright as the sun?
Since this is not true, it therefore means that not all light is reflected.
Also think about something like a candle, if brightness (intensity) does not decrease with distance, then a candle would look equally bright from 1 feet away as it would look like 100 ft away – is this your experience? So if you think it doesn’t hold true for a candle, why do you believe the sun is different? Light intensity decreases with distance and you experience this all the time.
Light gets in almost everywhere. There are places where there is zero light and it looks very different from normal dark places. Ive been on a submarine when the power goes out and you literally cannot perceive anything. Usually you are seeing the differences between something that gets 100% of the light vs 10% of the light. Your eye sees that as lit up vs dark or shaded.
> How come light can’t bounce off everything and manage to get into every crevice of Earth.
It does, pretty much. Few places are truly devoid of all light. A shadow is an area with less light, not no light otherwise objects in shadow would be invisible. Light can still strike objects in shadow by bouncing off of other objects.
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