Very few people have been lucky enough to see the earth from space, but thanks to the incredible spacecraft that have already explored neighboring celestial objects. Modern space exploration has gifted the people of Earth to see our big blue planet like never before. Currently in orbit around the Earth is one of humankind’s greatest achievements, the International Space Station.
This astonishing habitable artificial satellite is around 240 miles above our planet’s surface, traveling at about 17000 miles an hour, and has been visited by over 200 people since the year 2000. Most of the time, the satellite shows the blue color of the earth. Do you know why the earth appears blue from space?
Why does the earth look blue from space?
The planet Mars looks red, Moon looks ashy grey, and Earth looks blue. Mother Earth is called a blue planet due to the abundant water on its surface. Earth is the only planet in our solar system that has liquid water. Unlike Sun, the earth is not a light source. Planet earth receives light primarily from the Sun. Sunlight appears white, but actually, it is a combination of lights of several different colors. As the sunlight enters the water, the water absorbs all other colors of white light and reflects just blue light. This is a scattering phenomenon.
When we see the earth from space, the light from the sun hits the earth and gets reflected and reaches our eyes. About 71% of the earth’s surface is covered with water. That is, two-thirds of the surface is covered with water. So the 71% of earth water cover consumes white light and reflects just blue light. That means that almost 71% of Earth’s surface appears blue from outer space, and the remaining 29% looks greenish-brownish. That’s why the earth seems blue from outer space.
The color changes a lot as you go higher and higher. And it doesn’t change as fast; temperature also changes. The thickness of the air also changes. It’s all about as the air gets thinner at blue sky fades to black. So the sky is blue because of the thickness of the atmosphere above us, and the light bouncing off all the air molecules, and dust particles take away their atmosphere.
The space station orbits the planet approximately six times every 24 hours. And it has enabled astronauts to capture some incredible high-resolution footage of the planet’s vast cloud cover swooping auroras, bright blue oceans, impressive landscapes, and the magnificent nighttime glow of our city lights. On a clear night, the moon can be seen shining in the dark sky with a background of distant, glistening stars.
Over the years, many images have been captured of our planet from the moon. But the most famous one was taken by the Apollo 17 crew in 1972 during their journey to the lunar surface named Blue Marble. The picture showed a beautiful full view of the earth and was only enabled by the lucky alignment of the planets, the spacecraft, and the moon.
Read More: Why Is The Sky Blue?