What are Natural Light Sources and Why are They Natural?
- Mar 20
- 5 min read
Updated: Mar 23
In the universe we live in, both we humans and the universe itself produce light. However, unlike nature, the light we create is artificial, while that created by nature is called natural light sources. I will quickly present the differences between these two after explaining artificial light sources. This time it was a short introduction because the topic is clear; I'm getting straight to the point without losing momentum. So, what are natural light sources and where are they found?
Contents
What are natural light sources?
Natural light sources are anything that produces and emits light on its own, without any human intervention. Natural light can be found in countless celestial bodies, animals, plants, and even some minerals throughout the universe.
Natural Light Sources:
Sunlight
Stars
Fire
Lightning and Thunder
animals
Plants
Mushrooms
Northern and Southern Lights (Aurora Borealis)
Volcanic eruptions
Supernova Explosions
Now let's explain in detail why these natural light sources are natural and how they work.
Sunlight
The sun is the indispensable disco ball of our solar system, giving us life through the energy (heat and light) it produces thanks to nuclear fusion that has been going on for 4.6 billion years. The day-night cycle, caused by our planet's rotation, is a natural phenomenon. Therefore, sunlight is an indispensable natural light source, even beyond humankind.
Stars
All stars in the universe, including our Sun, are balls of fusion. Nuclear fusion in the cores of stars causes hydrogen atoms to combine into helium, resulting in incredibly high levels of gamma rays. However, these gamma rays cannot escape the shell because they are absorbed along the way. Once they reach the shell, they lose their energy and are released into space as visible light. The brightness of a star depends on its size and its distance from Earth.
Also, if you look carefully, you'll see the stars twinkling in the night sky. This is because light is refracted in the atmosphere. A photon (light) travels according to the density of the medium it passes through. In Earth's atmosphere , the density and temperature of the layers vary with altitude. When light passes through these changing air layers, it is slightly bent because each has its own refractive index. That's why the stars may appear to twinkle!
If you want to learn more about stars, you can check out this article: What is a Star and How Does it Form?
Fire
We consider fire to be both a natural and artificial light source. Various natural phenomena occurring in the world can cause fires or blazes. For example, a volcanic eruption can set a nearby forest on fire.
Lightning and Thunder
Lightning and thunder are caused by electrical discharges in the atmosphere. They usually occur when intense electrical charges are discharged within or between clouds.
Lightning is a violent burst of light caused by a high-voltage electrical discharge in the air. This burst ionizes air molecules, creating an electric current of millions of volts, and emitting intense light in the process.
Lightning is the visible burst of light from a lightning discharge that travels through the atmosphere. Lightning forms by reflecting or refracting light as it interacts with water vapor, dust, and other particles in the air.
Animals
Animals that emit their own light or glow naturally are known as bioluminescent organisms. Bioluminescence is the natural emission of light by living organisms, and the light is produced as a result of a chemical reaction within the cells of these organisms. The reaction involves the luciferin pigment, the luciferase enzyme, and oxygen, which are responsible for light emission. Some organisms possess specialized glands or organelles called photophores that produce light.
Bioluminescent organisms can be found in virtually any environment.
Animals that are Natural Light Sources | |
Marine Animals | Land Animals |
Jellyfish | Firefly |
Clusterwink Snail | Pyrophorini |
Bioluminescent Octopus | Starworm |
Anglerfish | Phrixothrix |
Midwater Squid (Abralia Veranyi) | Quantula Striata (Tropical Land Snail) |
Plants
Similarly, some plants, like some animals, can emit light, although this is not a very common phenomenon among plants. Some plants emit light through bioluminescence, chlorophyll fluorescence, or the use of nanoparticles that can store and release light.
Plants that are Natural Light Sources |
Bride's Lantern (Physalis Alkekengi) |
Algae (Dinoflagellates) |
Moon Ivy (Datura - Ipomoea Alba) |
Glow-in-the-Dark Fern (Pteris spp.) |
Kaudupul |
Mushrooms
Mushrooms also glow in the dark through a process called bioluminescence. The light is produced by a chemical reaction involving a light-emitting molecule called luciferin, an enzyme called luciferase, and oxygen. The reaction releases energy in the form of light, typically a greenish color with a wavelength of 520–530 nm. Bioluminescent mushrooms are found in temperate and tropical climates.
Mushrooms as a Natural Light Source |
Bitter Oyster (Panellus Stipticus) |
Panellus Pusillus |
Honey Mushroom (Armillaria Mellea) |
Mycena Chlorophos |
Lilac Mycena (Mycena Pura) |
Northern and Southern Lights (Aurora Borealis)
Auroras are natural light displays seen in the Earth's sky, primarily in high-latitude regions around the North Pole and Antarctica. They are the result of disturbances in the magnetosphere caused by the solar wind, a stream of charged particles emitted by the Sun. These disturbances alter the trajectories of charged particles in the magnetospheric plasma, causing them to fall into the upper atmosphere. The resulting ionization and excitation of atmospheric components emit light of varying color and complexity. The shape of the aurora also depends on the amount of acceleration given to the falling particles. The lights are typically green, but can also be red, blue, and purple, and are caused by the interaction between the Earth's magnetic field and charged particles from the Sun.
Volcanic eruptions
Volcanic eruptions occur when molten rock, gas, and debris are released from the Earth's crust through an opening called a volcano. The eruption can be explosive, sending ash, gas, and lava into the atmosphere and creating lava flows. And, of course, a small or large flash of light can result from this eruption.
Supernova Explosions
Supernova explosions aren't normally a natural phenomenon that continuously illuminates our planet, but we have a few spectacular examples in history that have lit up the sky: the SN 1006 and SN 1181 supernovae.
Known as the brightest supernova explosion in history, SN 1006 was recorded by observers in China, Japan, Iraq, Egypt, and Europe between April 30 and May 1, 1006, in the constellation Lupus.
SN 1181 was recorded in 1181 by Chinese and Japanese observers.
Now, if you're wondering what a supernova is, let me direct you to this section: What is a Supernova?
Is the Moon a Natural Light Source?
No. The Moon cannot be considered a natural light source because it does not produce its own light. Moonlight is reflected sunlight. The Moon's surface is composed of various types of rocks and soil, and these materials have different reflective properties, which affects the amount of light reflected.
