This paper takes part in the series essay competition of “great science” of Recordunkown.
Human beings are the only intelligent life on earth. They were born millions of years ago and formed civilization more than 5000 years ago. From the day of the formation of human civilization, some scholars in the forefront of mankind began to think about such a question: “who are we?” and “where are we?” Where are we from.
It is the scholars in ancient times who kept thinking about these ultimate problems that led to some interesting myths and legends. Due to the lack of scientific guidance, the ancients had no way to study and explore these ultimate questions, and they could only attribute the answers to God.
Later, with the continuous progress of human civilization, it entered the era of science and technology hundreds of years ago. With the help and guidance of scientific forces, scientists began to explore the truth of the world, and focused on the vast universe.
Before human beings walked out of the earth, we were full of yearning for the universe. At that time, we knew nothing about the universe. With the help of science and technology, mankind has finally stepped out of the earth and embarked on the road of exploring the mysteries of the universe. There are many mysteries in the universe, such as the origin of the universe, the origin of life, the existence of extraterrestrial civilization and so on.
If we want to explore the secrets of the universe, we need the assistance of astronomical telescopes and detectors. Although astronomical telescopes can observe very far away, it is only a kind of fuzzy observation. If we want to understand more detailed scenes of the deep stars, we still need detectors to go there.
After walking out of the earth, human beings began to launch probes into the universe, and the farthest one was Voyager. As we all know, the existence of extraterrestrial civilization has always been a mystery that the scientific community wants to solve. Just out of the earth, human beings began to search for extraterrestrial civilization.
In this project, Voyager spacecraft is the pioneer. It carries a CD-ROM recording the information of the earth and human beings, and keeps on advancing towards the vast outer solar system. Voyager spacecraft was launched in 1977. In the same year, NASA successively launched Voyager 1 and Voyager 2 spacecraft into space. Their mission is to move out of the solar system all the time, hoping to be captured by alien civilization one day, and know the existence of earth and human beings through the CD-ROM carried on them.
In the process of Voyager’s continuous progress, scientists not only hope to find out extraterrestrial civilization through them, but also hope to learn more about the solar system through them. As a result, Voyager has been sending all kinds of star photos to the earth.
Through these photos, we have a lot of knowledge of the farther parts of the solar system. In one of these photos, we are deeply thinking about it.
This picture is the home of the earth taken by voyager-1 at 6.4 billion kilometers away. As we all know, the best place to take pictures of the earth from space is the moon. Taking pictures of the earth in lunar orbit, we can see a huge and beautiful blue planet.
The earth is very beautiful in space. This kind of beauty is far beyond comparison with other planets. This may be the characteristic of life planet. Taking pictures of the earth from different star positions is also a wish scientists have always wanted to achieve. Voyager can just take on this task, so along the way, it will give a close-up of the earth in different star positions.
As Voyager keeps away from the earth, the earth becomes smaller and smaller. Reaching 6.4 billion kilometers away, Voyager took the last picture of the earth. The position of the earth in this picture is so dark that we can’t see the earth with naked eyes. Only by zooming in can we see a fuzzy particle of the earth.
In this picture, the earth is only 0.12 pixels, which is so small. Now Voyager 1 is more than 20 billion kilometers away from us. Even if we take photos of the earth, we can’t see the earth from the photos, even if we zoom in many times.
Seeing this makes many people silent. In our eyes, the huge home is too small in front of the vast universe. We used to think that the earth is the dust of the universe, and a grain of dust is actually very large, but through this picture, we realize that the earth is just a grain of dust in the solar system.
As we all know, the diameter of the solar system has reached more than 2 light-years, and it will take Voyager 1 at least 30000 years to fly out. The solar system is only one of 100 billion galaxies with a diameter of 100000 light-years. The earth is not even dust in front of the Milky way, and the solar system is only a dust in the Milky way.
So is the Galaxy Big? In fact, it is also very small, more than the Milky way in the original Galaxy Group, with a diameter of 10 million light-years. In this local Galaxy Group, there are dozens of galaxies like the Milky way, and the local galaxy is not the largest. On top of it, there are larger cosmic structures, such as the Virgo supercluster, with a diameter of 110 million light-years.
There are at least 100 Galaxy groups and clusters in Virgo supergalaxy. Is Virgo supercluster the largest cosmic structure? The answer is obviously not. There are many larger clusters on top of it. At present, the diameter of the observable universe has reached 93 billion light-years. Why is it the observable universe rather than the whole universe?
That’s because the universe is expanding. The farther away the galaxies are from the earth, the faster they are away from us. The galaxies 17 billion light-years away are faster than the speed of light. Therefore, the photons emitted by those galaxies can’t reach the earth, and naturally we can’t observe them.
The observable range is the range in which the expansion speed of the universe is less than the speed of light, while the expansion speed of the universe beyond the speed of light can not be observed at present. Even in the present observable universe, there are millions of superclusters, which may be just the tip of the iceberg in the vast universe. The real universe is much broader than we think.
In front of such a vast universe, does the earth dare to call itself dust? Of course not. At the same time, we should also understand that the earth is not even dust in the universe, and we can’t count the number of planets like the earth in the whole universe. Even if it is a small to extreme probability that intelligent civilization will be born, the number of civilizations in the universe will be more than we can imagine.
It has been 13.8 billion years since the birth of the universe. In such a long time, life and civilization will be born at different time points. Human civilization has only existed for about 5000 years. It can be seen that there may be many alien civilizations that are much stronger than human beings in the universe.
We still can’t find the alien civilization. The main reason is that human’s scientific and technological strength is limited, and there is no ability to go out of the solar system. And the alien civilization has not found the earth, probably because the universe is too vast, and the solar system itself is on the edge of a barren earth, it is not easy to be found.
Human beings can not find alien civilization, and it is not easy for alien civilization to find the earth, which is actually good news for human beings. Hawking once said that alien civilization may not be friendly. If alien civilization comes with hostility, then the huge power gap may bring great disaster to the earth and human beings.
A picture has brought us deep thinking, let us realize that the earth is so small, and human beings are also very small. If we want to become a bigger ant, we need to make continuous efforts to develop technology. Only when technology is really strong can we make human civilization continue and even become the overlord of the universe one day.