Zheng Yongchun is a researcher at the National Astronomical Observatory of the Chinese Academy of Sciences and a content author in the field of high-quality science popularization in today's headlines. As the first Chinese scientist to win the "Karl Sagan" Award, Zheng Yongchun has long been committed to astronomical research and astronomical science. In this sponge talk, "Uncle Mars" will take you back to Earth from outer space, let us jump out of the narrow concept of "anthropocentrism", and examine our own existence in the universe with a broader vision.
"Uncle Mars" Zheng Yongchun live speech video: click to watch
Hello everyone, my name is Zheng Yongchun, and I am a researcher at the National Astronomical Observatory of the Chinese Academy of Sciences. Because I'm mainly engaged in the study of the moon and Mars, you can also call me "Uncle Mars".
Chinese call the space outside the Earth "space", space, in a nutshell, is the open space of space. With the development of the space industry, the pace of human exploration of space is getting faster and faster, so what is space exploration in the end?
Exploration, in fact, is the two meanings of seeking and asking. What can we explore in the open space? And what can I ask for?
At this moment, you can imagine yourself sitting on a spaceship, we set off from the earth, fly into space, and gradually see more and more vast worlds, but also see more and more small us.
I was born in Shaoxing, Zhejiang, and our town is called the Three Realms because it spans three places; our village is called Changqiao, because one bridge spans two counties. Although it is a mountain village. But our vision is still quite large, and the old house in the village 100 years ago has the English word "the doorway" written on it. We often say that a child has a chance to go out, so we say that he is "out of the mountain", because he can see the outside world when he goes out of the mountain.
Later, I went to Beijing to study at a university, and then had the opportunity to work for several years at the Hong Kong University of Science and Technology. When I was in Hong Kong, the apartments offered by the school consisted of only a desk, a bed and a cupboard. I complained to my mentor, "The place where we live is too crowded. "My mentor told me: In Hong Kong, any place where you can straighten your legs when you sleep is called a big house. The thousand-foot mansion where the stars live is actually the square foot of the British system, which is actually less than a hundred square meters.
In the crowded metropolis, more and more people are caught up in anxiety. According to statistics, 173 million people in China have mental problems, and depression accounts for 4.2% of them. I live in Beijing, one of the fastest-paced and most stressful cities in China, but I seem to have a good attitude towards astronomy. I analyzed it, and it may be that our major is more open-minded.
A big guy once said: First set a small goal and earn it a hundred million. I remember a lot of people complaining about him, because 99% of us here firmly believe that in their lifetime, they will not make a hundred million in any case.
But we who study astronomy don't think so, we usually deal with various planets and galaxies. What is a billion on this earth? In the face of the brilliant stars of the Milky Way in the universe, it is a number.
Hawking, he did not have a muscle in his body, not a single joint to move. But his brain holds the entire universe and can calculate the operation and evolution of the entire universe. Hawking's example teaches us that our bodies can be confined to one place, but we should never forget that the human mind can be absolutely free.
It was Valentine's Day in 1990, and the Voyager spacecraft looked back at Earth from billions of kilometers of space and took a famous family portrait of the solar system. This is a famous photograph, and its name is "Dim Blue Dot".
The small, dark blue dot in the photo is our home, the Earth. This struck us deeply, as we were so small. We humans live on a grain of dust under the sun.
From Earth, we fly to the moon. The distance from the Earth to the Moon is 380,000 kilometers, which is equivalent to arranging the eight planets and passing them in turn to finally arrive.
If you look at the Earth from the moon, what is it like? Human ambitions in the 1960s and 1970s led to the miracle of the Apollo moon landings, and so far, 12 people around the world have landed on the moon, collecting 382 kilograms of lunar rock and soil.
This is another famous photograph of "Earth Rising". Astronauts who landed on the moon looked back at the earth from the moon, and what they saw was a blue "ground light" rising from the moon's horizon. In the distance, this blue planet is where we live. It is a vibrant planet with blue seas and deep green continents.
The moon, on the other hand, is a wild wilderness, with a huge temperature difference between day and night, and there is no trace of life. At this point you may discover how precious the earth is. It may be the only living planet in the universe, the home on which human beings live.
From the moon, we come to Mars, which is farther away from Earth. To date, more than 40 probes have flown over Mars. This is what the rover captured from the horizon of Mars: The Earth is a small, nearly invisible point suspended in the air.
The ancient Chinese called Mars "Yingchao" (because Mars is like fire and its whereabouts are uncertain, so it is called "Yingchao"), and "Yingzhi Shouxin" (Mars staying in the orbit of "Xinsu") is regarded as an unlucky celestial phenomenon. Westerners, too, see the red Mars as the god of war, and think it's related to the scourge of blood and light.
Looking back at Earth from above Mars, you will find that Mars has many similarities with Earth, for example, there are dust storms on Mars and an atmosphere. But the atmosphere on Mars is mainly composed of carbon dioxide, the surface radiation is very strong, and the temperature difference between day and night is also very large. There is no liquid water on its surface, no rivers, lakes and seas.
Earth and Mars are bathed in the same sun. Mars is far from the sun than Earth, so the sunlight on Mars will be weaker and the temperature will be much colder. Looking at Mars from the earth, you see the sunset red, but when you look at the earth from Mars, you see the sunset blue. In the solar system, The Earth is the third planet and Mars is the fourth planet, they are all in the habitable zone of the solar system, not far from the sun, but the earth is in the inner edge of the habitable zone, and Mars is in the outer edge of the habitable zone. If we are going to colonize other planets in the solar system, Mars is the only option.
Are there conditions on Mars to nurture life? Long ago, we found remnants of large-scale water flow on Mars. But no water source has been found. Now we've found water in the Martian soil, ice underground, water in the air. In 2015, we discovered liquid water on Mars, and in 2018, humans even found lakes with liquid water on Mars.
Not long ago, organic matter on Mars has also been discovered, the next step, can we find a small bug?
Astronomers once had a grand idea of transforming Mars. The atmosphere on Mars is mainly carbon dioxide, which can create a greenhouse effect when released. After the long-term greenhouse effect, Mars will regain its rivers, lakes and seas. In the future, can we transform Mars to resemble the home of life like Earth?
None of us in this room can see it, and all this can only be tested by our descendants.
Next, our ship came to the skies over Jupiter and Saturn. Earth is much smaller than these planets. Earth is only 1/1380 the size of Jupiter.
More than 400 years ago, Galileo observed that 4 celestial bodies orbited Jupiter, not the Earth. This discovery dealt a fatal blow to the "Earth Center Theory" that ruled the world for thousands of years at that time. The human worldview has been greatly shaken. It turns out that the earth is not the center of the universe, we are just one of the celestial bodies orbiting the sun.
If we go a little further, we can come to the sky above Pluto. In January 2006, the probe New Horizons was launched to detect the only untouched planet Pluto. But shortly after it flew out, Pluto was downgraded. New Horizons' mission has changed from exploring Pluto to exploring the "New World" of the solar system, the Kuiper Belt, where there is a large group of iced planets like Pluto.
In 2016, New Horizons flew over Pluto, showing us the love and frozen volcanoes on this frozen planet. What kind of miracles can we see further afield, on other planets in the Solar System's "New World"?
Farther into space, how do we humans explore it? Hawking had proposed a "breakthrough star-shooting" program that would launch lasers from the ground and accelerate the spacecraft when it reached 1/5 of the speed of light. We can take spacecraft to reach Proxima Centauri (the closest star system to us in the constellation Centauri) in about 20 years. This is currently the only possibility for humans to fly out of the solar system.
If we fly out of the solar system, we will find that the sun is really just a medium-to-small star. There are at least hundreds of billions of sun-like stars in the Milky Way, and they may also have their own "Earth."
The Kepler Space Telescope' main mission is to search for exoplanets, and it has found more than a thousand exoplanets, some of which are similar to Earth conditions, and they are called Earth 2.0 versions. These planets are closer to their stars, and we know their size, but we don't know if there's liquid water on them, if there's life? So if there is life on those planets, will the feeling of them looking at the earth be similar to the feeling we feel when we look at them?
Looking at the Milky Way, if you look closely, the Milky Way is actually just a small galaxy. Our galaxy is like a lonely island in a sea of stars.
And the starry sky in the distance is the beacon that guides us. I've made full maps of the Moon, Mars, the Solar System, and the Universe.
I suggest that everyone in their respective study rooms and classrooms can hang up another set of space maps. Because I believe that children who grow up looking at space maps must have a stronger sense of human responsibility than others. Because when you see space, you will know the smallness and loneliness of human beings, and you will learn to look up at the sky above us, learn to be in awe, and learn to remain humble.
Minimal and extremely large are related, and each planet is piled up in grains of stardust. In the past half century, human beings have still thought very shallowly about our existence. The future fate of mankind depends on whether we can understand the universe more deeply.
Voyager is still flying in deep space, and New Horizons is flying to the New World. China will also land on the moon in the near future, build a space station, and land on Mars.
But how long can we survive on this planet? This is a question that needs to be thought about. These questions are also the value of astronomers' continuous exploration.
When we gradually pull our perspective away and re-examine the earth, we realize that space is too vast, the earth is too small, human beings are too small, we ourselves are too small, so know more about space, maybe it won't help you solve the problem, but at least it can make the problem look "small".
Thank you.
The Sponge Speech is a series of speeches for contemporary youth hosted by Today's Headlines, which is held on average every two months. At each event, we invite 8 today's headline creators from different fields to speak, whether they are senior experts from science, medicine, psychology, photography, architecture and other fields, or they may be popular Internet celebrities in the travel, food, gaming, fashion industry. They will share their stories and experiences on the spot, as well as their unique knowledge and insights into their field.