On August 27, 2022, the 38th & 39th special events of “Science Popularization in China – I Am a Scientist” sponsored by the Science Popularization Department of the China Association for Science and Technology were successfully held at the Crowne Plaza Beijing Zhongguancun. Zhu Jin, a researcher at Beijing Planetarium and editor-in-chief of “Astronomy Enthusiasts” magazine, brought us a speech on the theme “How to Open Your Astronomy Dream”.
Zhu Jin’s speech video:
The following is the transcript of Zhu Jin’s speech:
I am very honored to have the opportunity to come to the scene to share astronomy with you. In the past 20 years, in addition to my work in the Beijing Planetarium, I have also done a lot of popular science work. Today, based on my experience, I will briefly talk about astronomy I know.
Speaking of which, astronomy may not be the same as many other disciplines you are familiar with. Astronomy is concerned with things beyond Earth’s atmosphere. For example, some people often classify weather as astronomy, which is actually wrong. Astronomy is concerned with a wider space, what we usually call the universe. Astronomers are more concerned with things beyond Earth.
In astronomy, both time and space, the scale is very large. Taking time as an example, we usually think about what will happen in a few decades at most, but we don’t care about what will happen in 10,000 years. But what astronomers care about is what happened in the universe from 13.7 billion years ago to the present . When astronomers talk about things, they often talk about a large time span. The spatial scale is also similar, with the entire range of space that astronomy is concerned with is almost 100 billion light-years in size. 1 light-year is almost 10 trillion kilometers, and 100 billion light-years can be imagined as a huge number.
Guest Speaker Zhu Jin: “How to Open Your Astronomical Dream” | Photo: Vphoto
In such a space range of 100 billion light-years and a time range of more than 10 billion years, all kinds of strange things will happen. Many of these things cannot be simulated in laboratories on Earth, and they are completely unexpected and interesting things. What astronomers do is to use telescopes or other observation methods to record what happened in the universe, to see how the universe moves and develops and changes under the control of physical laws.
Among many astronomical phenomena, the closest to us may be meteors. Meteors are luminous phenomena produced when small celestial bodies enter the Earth’s atmosphere. Although this phenomenon occurs within the atmosphere, these meteoroids themselves originate from outside the atmosphere, and are therefore also an object of study in astronomy.
Meteor Shower and Guo Shoujing Telescope | Photo courtesy of Zhu Jin
The other stars you see at night are farther away. Several planets are hundreds of millions to billions of kilometers away. The nearest stars other than the sun are 4 light-years away. Like the three stars in the Great Winter Triangle, they are farther away from us. The red Betelgeuse, 640 light-years away from us, may explode into a black hole one day in the future.
Winter Triangle | Photo courtesy of Zhu Jin
When using a telescope, we can observe objects farther away. For example, this nebula is 2,500 light-years away from us, and the picture taken by the Webb telescope is actually what it looked like 2,500 light-years ago.
Whether it is our sun or the nebula just mentioned, they are all distributed in a celestial system called galaxies. From the perspective of the entire universe, galaxies are a relatively common type of celestial body. The galaxy where the sun is located is the Milky Way that we are familiar with. It is made up of more than 100 billion stars, like a straw hat. This large disk is almost 100,000 light-years in diameter. Our Sun is about halfway between the center and the edge of the large plate of the Milky Way, not the center of the Milky Way, and is a very common star in the Milky Way.
GALAXY | ECKHARD SLAWIK
When we look in the direction of Andromeda on an autumn night, with the naked eye, we can see a particularly dim little cloud. This is not a star, but a very large galaxy. It has a diameter of about 160,000 light-years, contains hundreds of billions of stars, and is 2.5 million light-years away from us.
Andromeda Galaxy | Robert Gendler
The vast majority of galaxies in the universe are moving away from us, and the farther away galaxies are, the faster they are moving away from us. But the Andromeda Galaxy is close to us, and in a few billion years, the Andromeda Galaxy may collide with our Milky Way and form a larger galaxy.
Yet we can’t wait 4 billion years to see what the outcome will be. The beauty of astronomy is that, when we look at the entire universe, we can see all kinds of celestial bodies in various stages of evolution, from just born to the end of life. Antenna galaxies, for example, 45 million light-years away, are merging.
Antenna Galaxy | NASA/ESA/Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration
From the shooting stars in front of our eyes, to the far edge of the universe, astronomy is concerned. Many astronomical phenomena can be directly participated by the public, such as solar and lunar eclipses, meteor showers, or planetary conjunctions and so on. The range of celestial phenomena that can be observed is often very large, and even visible all over the world. Therefore, astronomy is also a subject that is particularly suitable for cultivating children’s curiosity. We can observe the same celestial phenomenon together and feel the mystery and shock of the same starry sky.
The 1866 (left) and 1833 (right) appearances of the Leonids | public domain
These are particularly good times, and we can learn about astronomy in a variety of ways. I myself work at the Beijing Planetarium, which is a good window for children to get in touch with astronomy. In addition, we now have various research activities, various astronomical competitions, and even magazines such as “Astronomy Enthusiasts”, which are all good ways to learn astronomy. Astronomy and spaceflight also have many combinations. Astronomy is looking up at the stars, while spaceflight is down-to-earth.
In the past 20 years of work in the planetarium, I have always hoped that more children could be “fudged” into scientists, or “fudged” into astronomers. I hope that in the future, more of our children here can become scientists, thank you!
Guest Speaker Zhu Jin: “How to Open Your Astronomy Dream” | Photo: Vphoto
Author: Zhu Jin
Editor: Han Yueyang
Typesetting: Yin Ningliu
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[Extended reading] Is it possible to emit light around a black hole? Yes, and it may not be weak | Zuo Wenwen
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