Planet Earth is known by other names such as the blue planet. It is the only planet so far known in the entire universe to harbor life. This is because it is at the perfect distance from the sun to support temperatures that can support life as we know it. However, many people wonder Why is Earth called the blue planet?.
In this article we are going to tell you about the main reasons why Earth is called the blue planet.
Why is Earth called the blue planet?
Earth is called the blue planet because of its abundance of water, which can be seen in the vast blue space. The area of the Earth is approximately 510 million square kilometers, of which more than 70% is covered by water. The blue color distinguishes it from other planets such as Mars, Mercury, Jupiter, Uranus, etc.
Most of the blue planet's water is frozen or salty, and only a fairly small portion is fit for human consumption. The main oceans are the Atlantic Ocean, the Pacific Ocean, the Indian Ocean, the Arctic and the Antarctic.
Although the depth of the oceans varies in different regions, a large part of our planet has never been explored because it lies in the depths of the oceans. It is still very complicated for humans to use all their technology to be able to study it in its entirety.
This important fluid is only abundant on Earth, and it is impossible to find signs of their presence in any kind of physical state in our solar system. According to the research done so far, no other planet has oceans and enough oxygen to support life.
The blue color of the oceans
Earth has five main oceans: Pacific Ocean, Atlantic Ocean, Indian Ocean, Antarctic Ocean and Arctic Ocean. Our planet is seen from space as a large sphere filled with various shades of blue made up of all these oceans, each with a different color and character.
This is the main reason why the Earth began to be called the blue planet, however, it was not the water that gave it that color. Water is colorless, and although it is believed to reflect the color of the sky, it appears blue only because of the abundance of water, and the spectrum of light has difficulty passing through it, as is the case with the ocean.
color wavelength
Red, yellow or green have longer wavelengths than blue, so water molecules absorb them more easily. Blue has a short length, so the more water there is in the light space, the more blue it will appear. It can be said that the color of the water is related to the intensity of the light, and in some areas it is very common for the hue of the water to change to green.
This has to do with the presence of algae, the proximity to the shore, the agitation of the sea at that moment, and the various sediments that are usually found in the water that accentuate the color more than the blue.
It is also known that phytoplankton, the water-dwelling microbes responsible for providing nearly half of the oxygen humans breathe, is partly responsible for the color changes of the water.
Phytoplankton contain chlorophyll and are located in the shallower parts of the water body to capture as much light as possible. When they are all concentrated in the same area, the sea turns very green instead of the traditional blue.
Why is the Earth blue when seen from space?
The Earth was not always blue, in fact, it has changed a lot over the millions of years it has existed. At first, the composition of Earth's atmosphere was very different from what it is today: the atmosphere that makes the sky, Earth, or Earth appear blue from space. The constant volcanic eruptions on our planet release enormous amounts of water vapor into the air, which eventually forms oceans as it settles.
In those oceans, algae began to be born and grow. They consume carbon dioxide and produce oxygen. If we take into account that carbon dioxide was very abundant at that time and that there were no animals consuming oxygen, the proliferation of algae over the centuries managed to change the composition of the atmosphere until it reached levels similar to those we have today. now.
The fact is that when we observe the sky during the day it is blue, The same thing happens when we observe the earth from space, the earth's atmosphere presents us with a blue tint. This has a lot to do with the composition of our atmosphere and the theory of light.
The source of light on our planet is the sun. The star emits different types of light that we can combine to receive as white light. To get to our planet 8 minutes after leaving the sun, this light must first pass through different layers of our atmosphere. As we mentioned, there are different molecules that make up our atmosphere, but of all these molecules, the main one is nitrogen. A characteristic of nitrogen molecules is that when they receive light, they re-emit it in another direction depending on the wavelength of the light.
When light reaches the atmosphere, the long rays (red, green, and yellow) strike the surface or are re-emitted into space, while the shorter blue rays are reflected and scattered. Therefore, we think that the sky is blue.
Since when is Earth called the blue planet?
In fact, the nickname of the blue planet is quite recent, which is logical when we consider that it has not been that long since we have been able to observe the appearance of the Earth from space. The reality is that this name he made a fortune in the 1960s and 1970s, became popular, and has been broadcast to this day.
At that time, the world was divided into two large political and economic blocs, the capitalist bloc headed by the United States and the communist bloc headed by the Soviet Union. This period in history is known as the Cold War because while there was no direct conflict, the two countries clashed in every other possible scenario. During these years the so-called space race took place, in which both countries tried to be the first to carry out manned space travel and land on the Moon.
The fact is that the Russian and American cosmonauts who first came out of our atmosphere and observed the Earth noticed that from “there” our planet looks like a big blue sphere, it is the blue planet.
I hope that with this information you can learn more about why Earth is called the blue planet.