2020-11-14

How does it feel to look back at the earth from other celestial bodies? Why is it frightening?

By yqqlm yqqlm

With the continuous development of human civilization, our understanding of the earth is gradually deepening. At first, the sages thought that this world was just a flat plate without boundaries, not a sphere.

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Remember the ancient Greek philosopher and mathematician Pythagoras (580 BC -500 BC) As soon as he proposed the hypothesis that the world is spherical, he was challenged by his classmates.

In a class, Pythagoras expounded his views on the world, thinking that the earth is spherical rather than flat. His classmates stood up and retorted:If the earth is spherical , Then don’t the other half of the people head down and feet up, so why don’t they fall?

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It is true that this problem was difficult to explain at that time, but in Modern high school students understand the principle.

Since the last century, human beings have truly begun space exploration, and they have also flown out of the earth into space. The world we live in is a blue planet with the naked eye, 70%of the surface is covered by sea water. Covered, at 9:7 am on April 12, 1961, the former Soviet Union astronaut Gagarin entered on the”Vostok 1 spacecraft” In space, it took 108 minutes to orbit the earth and finally returned to the earth safely. It was the first time that human beings who had evolved for millions of years witnessed the whole picture of the earth with their own eyes.

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1, look back at the earth from the moon

From the late 1960s to the early 1970s, NASA launched the Apollo manned mission to the moon, a total of six Twelve astronauts were sent on the surface of the moon, leaving human footprints there. These astronauts were also people who looked back at the earth from the moon with their own eyes.

But the most famous photo was not taken by them, but from Apollo 8. On December 24, 1968, astronaut William Ender on Apollo 8 took Created this beautiful picture of the Earth”Earthrise”. Looking back at the earth from 380,000 kilometers away, it is like a beautiful porcelain plate hanging high in the sky.

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2. Looking back at the earth”on Saturn”, it brings us different Feeling

Of course, the farthest human footprint is the moon, which is 380,000 kilometers away. Naturally, it is impossible to go to Saturn and look back at the earth with your own eyes, but human probes have already flown to the distant sky. The farthest one is Voyager One, which is currently about 22.4 billion kilometers away from the earth. Saturn is one of the eight planets in the solar system. It is a gas giant. Its orbit is outside Jupiter and is about 10 astronomical units away from us. Of course, the distance between the Earth and Saturn changes dynamically with their respective revolutions.

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In 1997, NASA launched the Cassini-Huygens Saturn probe, It is mainly used to detect Saturn and the largest satellite Titan. It has been working for more than 20 years, and Cassini was controlled in 2017. Dive into Saturn and end its exploration mission.

September 15, 2006, the Cassini probe took a shot with a wide-angle camera as usual A photo. At that time, it was 2.09 million kilometers away from Saturn and 1.4 billion kilometers away from Earth.

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< p>The photo was sent back to the surface of the earth. Scientists discovered something incredible during the analysis and processing. After the photo was enlarged, two small spots appeared between Saturn’s A ring (top) and F ring (bottom), one of which was more It is brighter, and the other is slightly darker. From the shooting point of view of the Cassini at the time, this is our earth and moon.

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3. Voyager One looks back at the earth, 6.4 billion kilometers away Looking back

In 1977, Voyager 1 embarked on its interstellar journey. Its mission was to detect Jupiter and Saturn and their moons, and then continued to fly into deep space. Is flying out of the solar system. On February 14, 1990, it had completed its primary detection target, and then it was heading out of the department. At this time, the scientist controlled it to turn the camera and took a photo facing the direction of home. This became the most famous photo of the earth”dark blue dot”. In the photo, the earth is less than one pixel, so small and pitiful.

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When the photo was taken, Voyager 1 was only 6.4 billion kilometers away from the earth, which is the same as the radius A light-year solar system is relatively insignificant.

How does it feel to look back at the earth from other celestial bodies?

At present, human beings cannot personally experience looking back at the earth from a long distance, but our detectors have helped to achieve this goal. The smaller the earth, the more frightening and disturbing. Why is this?

The goal of mankind in the future is the stars and the sea, because we are an inactive species, continuous innovation and continuous progress. This is our portrayal. But these photos sent back to the earth from a long distance suddenly made us truly realize the”big” of the solar system and the”big” of the universe. Humans may never be able to fly out of the solar system, as if we were blocked.

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The development and evolution of mankind over millions of years are concentrated on this insignificant”little blue dot””The development and progress that I think is not as big as the”grain”, which naturally makes people feel uneasy.

But to think about it from another angle, this may be more interesting. It can be full of expectations for the future of human civilization.


Text/scientific black hole, image source network invasion and deletion.