FAQ/Sun

Where does the sun go?

Most people ignore refraction and air density in their arguments. When things get farther from you they appear smaller. And they also appear to descent to the horizon. However the horizon we see is significantly higher than the true horizon. This is because air is not transparent!

When you watch a sunset, you are also looking through 1000s of miles of low, middle and high altitude air. The high altitude air is thinner. That is why clouds float and why helium balloons rise. Due to buoyancy/density. It's also why boats float. So the thin upper atmos forms a wall of air after 100+ miles. This blocks your view of the sun and causes it to get cut off bottom first.

The sun changes color gradually, things get darker before sunset. Also the light curves towards you. This is because light refracts in the upper atmos. You can prove this by looking at examples of "advances sunrise" and "delayed sunset". The sun has been seen to set, then rise again an hour later, then set an hour later and so forth. Wikipedia actually gave this advanced sunrise example.

Light curves up in the upper atmos and down in the lower atmos. This is due to Snells Law. Also the limits of our eyes, curved lenses and perspective play a role in this. Things below you such as the ground converge to the horizon. A curved lense on your eye or camera lense can produce a similar effect. When the sun goes below the horizon, there is still light for a good protion of the day so whether or not it is visible verses whether some of the lights reaches you are decoupled. However the things most people seem to forget about are air density and refraction/Snells Law.

Snells Law

Snells Law is a method for calculating refraction. When things go from low refraction to high refraction, light angles down. When things go from high refraction to low refraction light angles up. This bends/changes the angle of light.

Snells Law disproves "far away" stars because light would eventually be bent after millions of miles. The probability is too high that even a 0.0000001 degree chance in angle would cause the light to miss us completely making consistent star trails impossible. Our atmos forms a density gradient. Things that are buoyant rise (like clouds and balloons). Helium and Hydrogen rise, Hydrogen above Helium so for example, when light goes from Hydrogen to Helium light bends up towards you.

All chemical/elements have a refractive index so light will always change slightly everywhere it goes. these angular changes become extremely significant over many miles. When combining elements this can greatly exaggerate the refractivity. For example, by placing sugar in water you can see light bend using a laser pointer. Add to this diffusion, reflection and other important things that can happen to light in the atmos which require study.