Earth is called a blue planet because due to its great abundance of water it appears blue. The land is approximately 510 million km² in size and just over 70% is covered by water. The blue color differentiates it from other planets such as Mars, Mercury, Jupiter, Uranus, and many others.
Most of the water on the blue planet is frozen or salty, and only a fairly small percentage is fit for human consumption. The main oceans are the Atlantic, Pacific, Indian, Arctic, and Antarctic.
Although the depth of the oceans is variable in different areas, much of our planet has never been explored, since it is under the depths of the sea. It is still very complicated for the human being using all his technology, to be able to study it in its entirety.
This vital liquid is abundant only on planet Earth, in our solar system it has not been possible to find signs of its existence in any type of physical state. No other planet, according to studies so far, has oceans and enough oxygen for life to originate.
The blue of the Earth's oceans
The planet Earth has five great oceans: the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Antarctic Glacial Ocean and the Arctic Glacial Ocean.
Our planet seen from space is a large sphere full of different shades of blue generated by the combination of all these oceans, each one with a different color and characteristics.
This was the main reason why the Earth began to be called the blue planet, however, it is not the water that gives it that color.
The water is colorless and although it is believed that it reflects the color of the sky, its bluish hue is simply due to the fact that in large quantities, it is difficult for the spectrum of light to pass through it, as is the case of the oceans.
The wavelength of colors
Red, yellow or green colors have a longer wavelength than blue, making it easier for water molecules to absorb them.
Blue has a short length and for this reason, the more water in a lit space, the more blue it will appear. You could say that the color of the water is related to the amount of light, and in some regions, it is common for the water to change its hue to greenish.
This is related to the presence of seaweed, the proximity to the coasts, the agitation that the sea has at that time and all kinds of sediments that are normally found in the water and that can highlight more a color over the blue.
It is also known that phytoplankton, a microorganism that lives in water and is responsible for almost half of the oxygen that humans breathe, has some relationship with changes in the color of water.
Phytoplankton contains chlorophyll and is located in the shallowest part of the water to capture as much light as possible.
When they are all grouped in the same area, the sea can become quite green instead of its conventional blue color.
References
- "The Blue Planet" on Global Change. Retrieved on September 03, 2017 from Global Change: globalchange.umich.edu.
- Silvertant, M. "Why is Earth known as the blue planet?" (January, 2017) on Quora. Retrieved on September 03, 2017 from Quora: quora.com.
- Siegal, E. "Why is Earth Blue" (September 2015) in: Medium. Retrieved on September 03, 2017 from Medium: medium.com.
- "Phytoplankton" in Science and Biology. Retrieved on September 3, 2017 from Science and Biology: Cienciaybiologia.com.
"The Earth: hydrosphere and atmosphere" in Astromia. Retrieved on September 3, 2017 from Asreomia: astromia.com.