Light and our atmosphere (some quantum physics)

In summary, the yellow/orange color of the moon near the horizon is due to light passing through more of the Earth's atmosphere, causing it to appear more orange as blue light is scattered. The moon appears white in the middle of the sky due to less light passing through the atmosphere. The blue hue of the sky is also caused by scattering in the atmosphere. The apparent size of the moon over the horizon is an optical illusion, with no actual difference in measurements. Ozone mainly absorbs infrared light, but its UV-absorbing capacity comes from the formation/breakup cycle involving UV and oxygen.
  • #1
victorhugo
127
5
I was looking at the moon rising and noticed that it starts off quite yellow/orange and gets more and more white as it reaches the middle of the sky.
Why does it look bigger? I'd imagine it's something to do with refraction, but how exactly does it work?
Does the moon look more orange closer to the horizon because the light to reach it took a longer path through our atmosphere, and, therefore, more blue light/UV light has been absorbed/scattered and so more light in the lower energy spectrum reaches the moon? I thought of this since it appears white in the middle of the sky, where almost no light reaching it has passed through our atmosphere (ignoring the light that came back from it to hit earth)
Oh and it to my assumption, since our ozone blocks light in the UV/UVB range, does that mean it will also block some bluer/purple light?

Does the sky look blue because the molecules that make up our atmosphere let lights through and absorbs some of the blue light and re-emits everywhere, making it so the sky appears to be blue?
 
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  • #2
You're correct on both counts - reddening of the Moon and the Sun as well as the blue hue of the sky are all caused by scattering in the atmosphere. The following article explains it in depth:
https://en.wikipedia.org/wiki/Rayleigh_scattering

The apparently larger moon over the horizon is an optical illusion. There's no actual difference in measurements (it's actually a tiny bit smaller over the horizon, since it's farther away). I've seen a number of explanation for the illusion, but since it's a matter of psychology, its hard to make ironclad statements about the underlying reasons.

Ozone vibrational modes absorb most strongly in infrared (so it's a greenhouse gas); its UV-absorbing capacity comes from the formation/breakup cycle involving UV and oxygen.
 

What is light and how does it interact with our atmosphere?

Light is a form of electromagnetic radiation that is visible to the human eye. It is composed of particles called photons that travel in waves. When light enters our atmosphere, it can be scattered, absorbed, or reflected depending on its wavelength and the composition of the atmosphere.

Why does the sky appear blue during the day and red during sunrise/sunset?

This phenomenon is known as Rayleigh scattering. The Earth's atmosphere is composed of various molecules and particles that scatter sunlight in all directions. Blue light has a shorter wavelength and is scattered more easily, making the sky appear blue. During sunrise and sunset, the sunlight has to travel a longer distance through the atmosphere, causing the shorter wavelengths (blue) to be scattered and leaving the longer wavelengths (red) to be visible.

How does our atmosphere protect us from harmful radiation from the sun?

The Earth's atmosphere contains a layer called the ozone layer, which is responsible for absorbing harmful ultraviolet (UV) radiation from the sun. Ozone molecules in this layer absorb and convert UV radiation into heat energy, protecting us from its harmful effects.

What is the greenhouse effect and how does it affect our atmosphere?

The greenhouse effect is a natural process that occurs when certain gases in our atmosphere trap heat radiating from the Earth, creating a warming effect. These gases, such as carbon dioxide and water vapor, act like a blanket, keeping the Earth's surface warm enough to support life. However, an increase in these gases due to human activities can lead to an enhanced greenhouse effect, causing global warming and climate change.

How does quantum physics play a role in understanding the behavior of light?

Quantum physics is the branch of physics that studies the behavior of matter and energy on a very small scale, such as atoms and subatomic particles. It is essential in understanding the behavior of light as it explains how light behaves both as a wave and a particle, known as wave-particle duality. Quantum physics also helps explain phenomena such as the photoelectric effect and the emission and absorption of light by atoms.

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