One of the best things is to sit and watch the rising sun while you sip on a cup of coffee or catch a ride to get to work. If you have been observant, you will notice the sun appears to be reddish when it rises in the morning. And the sun appears to be white during noon, and you must have wondered why this occurs.
Over the years, there have been different theories that try to explain why the sun appears reddish early in the morning and white at noon. However, with all the theories, there seems to be one conclusion that has been accepted as the undisputable reason the rising sun appears reddish.
We live in a universe full of many unexplainable things, there are many things that man has been unable to provide explanations to, so we have no choice but to wonder what they are. Nevertheless, we will still live out our lives while enjoying the mysteries of our universe.
Why Does the Rising Sun Appear Red in Color?
Colors are one of the things that make our planet beautiful, the green plants, the blue sky, the red sun, the rainbow, amongst others. There are explanations as to why we have these colors, but we will specifically look at why the sun appears red when rising.
Light rays from the sun travel a longer distance in the earth’s atmosphere during sunrise. So, the rays of sunlight are scattered more than they usually are during other times of the day.
However, the least scattered light is red because it travels the longest distance and has the longest wavelength (distance between a part of a light wave and the successive part).
All the other light rays in the visible spectrum are more scattered because they have shorter wavelengths and travel short distances. So, this is why the sun appears red during sunrise.
Another way of explaining it will be, during sunrise early in the morning, and the sun is usually near the horizon. As a result of the sun’s position, sunlight has to travel a long distance through the atmosphere to get to us.
Due to the long-distance sunlight has to travel through, most of the blue light is scattered because it has a short wavelength. Red light has a longer wavelength and travels more, so during sunlight, the light reaching our eyes consists mainly of red color. And, the sun and the sky around the sun appear red early in the morning.
We will see why sunlight scatters when traveling through the earth’s atmosphere.
There are various gas molecules in the earth’s atmosphere, like oxygen, nitrogen, and carbon dioxide. Before sunlight gets to the earth, it has to pass through these molecules.
The molecules absorb light of different wavelengths; lights with shorter wavelengths are absorbed completely. As a result of blue light scattering, the sky appears to be blue during the day.
Wavelength of Spectrum of Light
Now you would be curious to know about different wavelengths of different colors in the spectrum of light. Check out this table that mentions the wavelength and frequency of all the colors in the VIBGYOR:
Why Does the Red Color Only Appear During Sunrise and Sunset?
If you have paid careful attention to sunrise and sunset, you will notice that the sun appears to be red at both times, but the sun is more reddish at sunset than at sunrise. If you have not noticed this, you should take some time to watch when the sun rises and sets.
We mentioned earlier that the light from the sun has to travel through the earth’s atmosphere, where it gets scattered before reaching us. It is important to note that there are other colors, including yellow, green, blue, and violet. But red and blue are often talked about because they have the longest and shortest wavelength, respectively.
Sunlight travels the longest through the earth’s atmosphere at sunrise and sunset because of the spherical geometry of the earth; at sunrise when the sun is at the horizon and sunset when it is at zenith. When the sun is in any of these positions, there is more probability for lights with short wavelengths to be more scattered.
Another important thing to know is that the scattering is relative to the quantity and size of the scattering particles. At night, the atmosphere is cool, so dust particles and aerial particles are settled by morning but are dispersed by evening.
Also, the spinning of the earth affects the color of the sun at sunrise and sunset. The earth spins from west to east, so we move towards the sun, which is east in the morning, and away from the sun in the evening, which is west. There is less atmosphere for light to travel through at sunrise than at sunset.
The refractive index of the prism plays a significant role here. It is the measurement of bending light when it passes through a certain medium. So, when the light with a maximum refractive index of the prism will be the last to be visible. Red has the minimum refractive index, so we are able to see it first.
You can also try this with an experiment using a prism and a light source. Place a prism on a surface, now pass a light source from one end of the prism. The light rays that come out of the other side will have all light, and the more dominant ones will be more visible.
It is simple science that a lot of people might not know, but with the right explanation accompanied by some experiments, things can be made clearer.
Why Does the Sun Appear To Be White at Noon?
The sun appears to be white at noon because, at that time of the day, the sun is overhead, and when it is in that position, there is less air for sunlight to travel through. Remember, we said, the scattering of sunlight depends on the quantity and size of the scattering particles (aerial and dust).
At noon, the particles in the air are reduced, so the light flowing through the atmosphere is not scattered as much as it is at sunrise or sunset, so we see the light as it is.
In reality, the light from the sun is white, but the clouds act as prisms that break up the white light into all the colors of the rainbow (red, orange, yellow, green, blue, indigo, and violet).
There are no such particles present in the air at noon that makes the scattering least to none. With lesser air to travel and reduced scattering, all the light rays are combined to form white light.
So, when the sun is overhead, sunlight has to travel a short distance through the atmosphere with little particles to scatter the rays of sunlight. So, the sunlight has all component colors in the right proportion, so the sun appears to be white at noon. With little distance for the sunlight to travel, there is reduced scattering.
That’s why when you look at the noon sun, it appears to be white. When gradually it moves to the horizon, the presence of dust and suspended particles will increase the scattering of light resulting in the red hue of the sun during the sunset.
Why Does the Sun Rise in the East?
There is a popular saying, “the sun rises in the east and sets in the west.” Have you ever wondered about the person that came up with the expression and what propelled it? Well, this expression might not be true, and we will examine the facts to ascertain that.
The expression was developed when men believed the earth was flat and the sun revolved around the earth. Now, we know that the sun, stars, and moon are in a fixed position at the center of our solar system and the earth and other planets revolve around them. So, if the sun is in a fixed position, there is no way it rises and sets.
Nevertheless, we will examine why it seems the sun rises in the east and sets in the west. The earth rotates towards the east, so all the heavenly bodies appear to rise from the east; rather, sunlight is shone on the eastern part of the earth because that is where the earth spins towards.
The sun is not moving from its place that causes sunrise and sunset; it’s our earth that is rotating. So, the day and night changes that you witness on the earth are due to such rotation.
As the earth rotates, different parts of the earth are exposed to the sunlight, so as a location turns towards the sun and enters its light, it seems like the sun is rising from the east. And as another part of the earth enters the sun’s light and the last location leaves, the sun appears to set in the west.
So, the earth rotates from west to east on its axis, making the sun and moon move from east to west. The earth’s rotation is responsible for the day and night. When the earth rotates from west to east on its axis, we are able to see the sun rising in the east.
Here is an interesting fact, the sun only appears to rise due east and set due west on only two days of the year, the fall and spring equinoxes. The sun rises either in the southeast or northeast and sets in the southwest or northwest on other days.
The points of the sun rising and setting change every day. During the summer solstice, the sun rises farther northeast than ever and sets far northwest.
So, next time someone asks you why the sun comes up from the east and not from the west, you can tell them that the sun is not going anywhere. It is static, it is our earth that is rotating on its axis.
There are plenty of other secrets regarding our solar system that people often are curious about but are not zealous enough to find answers to. The east-west dilemma is just one of them.
Why Does the Sun Disappear at Night?
Looking at the heavenly bodies (the sun, moon, and stars) from the earth, it looks like they are moving, and the earth is in a fixed position. But, in reality, the heavenly bodies are in a fixed position, and the earth revolves around them. So, if you wonder why the sun disappears at night and where it goes, we will look into it.
So, what exactly is the reason? Where does the sun go at night? And how it comes the next morning?
The sun does not disappear at night; neither does it mysteriously appear during the day. The sun is at the center of the universe, and all the planets revolve around it. What makes it look like the sun disappears at night is the revolution of the earth. Different parts are exposed to sunlight as the earth revolves around the sun.
We know that the sun is in a static position. It is not moving from its place, and it is our earth that is revolving around it for 365 days. At the same time, the earth rotates on its axis for 24 hours or so.
Sun seems to be revolving because our earth is not only orbiting but also rotating on its axis. So, not all parts of the earth will be receiving sunlight at the same time. When the sun completes half of its rotation, one side will receive the sun, the other side will be dark.
The sun will always shine, but it is impossible for it to provide sunlight to all parts of our planet at the same time. To prove this, you can try shining a flashlight on a ball, and you will see that the light will only shine on the part of the ball facing the flashlight. This is the same thing with the earth and the sun.
As the earth revolves, the part of the earth facing the sun experiences daytime, and for the other parts, it is nighttime. So, the sun does not disappear at night, and it only shines on other parts of the earth.
Why is the Moon Not Visible During the Day?
Now that we have talked about the sun, it would be unfair to leave the moon and not explore its secret. Just like the sun does not appear in the night sky, the moon vanishes as soon as the sun rises.
You would know that the sun reflects its light on the moon, which is when it becomes visible to us. So, during the day, there is lesser to no chance of reflection. It also depends on the position of the moon in the sky that will determine its visibility.
However, there are few instances during the day when we can spot a reflection of the moon when observed closely. It happens because, just like the night, the moon’s surface reflects the sun’s rays.
The same thing happens with the star. They are at an infinite distance from us, and it takes a lot of time for their light to reach earth. During the day, the sun is so bright that it conceals all the other light. However, during the night sky, stars are easily visible if the sky is clear from the clouds.
Our universe is filled with mystery that is yet to be discovered. Scientists and astronomists are continuously researching their way through the universe in order to find new secrets that can reveal more about the place we reside in.
The above-mentioned were a few things related to the relation of the sun, earth, and moon regarding how they appear in the sky.
If you are more curious about learning about them, you should keep kindling your curiosity as there is an ocean of information and knowledge that you can acquire today with respect to our universe and its celestial bodies.