What is astronomy?

Astronomy Astronomy is the study of the structure and development of celestial bodies and the universe in space. The contents include the structure, properties and operating rules of celestial bodies. By observing the radiation emitted by celestial bodies to the earth, we can find and measure their positions, explore their motion laws, and study their physical properties, chemical composition, internal structure, energy sources and their evolution laws. Astronomy is an ancient science and has played an important role since the history of human civilization.

Chinese name astronomy mbth astronomy category basic discipline research direction Space celestial bodies, structure and development branch theoretical astronomy and observational astronomy.

Research significance

astronomy

The study of astronomy is of great practical significance to our life and has a great influence on human's view of nature. Ancient astronomers determined time, direction and calendar by observing the sun, the moon and other celestial bodies and phenomena. This is also the beginning of astrometry. If people observe celestial bodies and record astronomical phenomena, the history of astronomy will be at least five or six thousand years. Astronomy occupies a very important position in the early history of human civilization. The pyramids in Egypt and Stonehenge in Europe are famous prehistoric astronomical sites. Heliocentrism of Copernicus once liberated natural science from theology; Kant and Laplace's theory about the origin of the solar system opened the first gap in the metaphysical view of nature in the18th century.

The emergence of Newtonian mechanics, the discovery of nuclear energy and other events that play an important role in human civilization are closely related to astronomical research. At present, the study of high-energy astrophysics, compact stars and the evolution of the universe can greatly promote the development of modern science. The study of celestial bodies in the sun and solar system, including the earth and artificial satellites, has many applications in aerospace, geodesy, communication and navigation. Astronomy originated from ancient human acquisition of seasons and divination activities.

Astronomy follows the development path of observation-theory-observation, and constantly extends people's horizons to new depths in the universe. With the development of human society, the research object of astronomy has developed from the solar system to the whole universe. Now astronomy has formed three branches according to the classification of research methods: astrometry, celestial mechanics and astrophysics. According to the classification of observation methods, several sub-disciplines of optical astronomy, radio astronomy and space astronomy were formed.

research objects

With the development of astronomy, the detection range of human beings from the sun and the moon to the stars in the sky has reached a distance of about 654.38+0 billion light years from the earth. According to the scale and scale, the research objects of astronomy can be divided into:

Planetary grade

Including planets in the planetary system, satellites orbiting planets and a large number of small celestial bodies, such as asteroids, comets, meteoroids and interplanetary matter. Star system.

Stellar grade

At present, people have observed hundreds of millions of stars, and the sun is just a very common one among countless stars.

Galaxy hierarchy

The solar system where human beings live is just the corner of the Milky Way galaxy composed of countless stars. The Milky Way is just an ordinary galaxy. In addition to the Milky Way, there are many extragalactic galaxies. Galaxies have further formed larger celestial systems, such as galaxy clusters, galaxy clusters and supercluster.

universe

Some astronomers have proposed a total galaxy one level higher than the supercluster. According to today's understanding,

The total galaxy is the universe that can be observed by human beings at present, with a radius of more than 65.438+0 billion light years.

One of the hottest and most unconvincing topics in astronomical research is the study of the origin and evolution of the universe. There are endless theories about the origin of the universe, among which the most representative, influential and supportive one is the Big Bang theory put forward by American scientist Gamov and others in 1948. According to this theory, the universe was born in a violent explosion about 654.38+03.7 billion years ago. Then the universe expands, the temperature drops, and all kinds of elementary particles are produced. With the further decline of temperature of the universe, matter began to collapse due to gravity, and gradually condensed. When the age of the universe is about 10 years, galaxies began to form and gradually evolved into what they are now.

research method

The object of astronomical research is huge in scale, extremely long in time and extreme in physical characteristics, so it is difficult to simulate it in the ground laboratory. So the research methods of astronomy mainly rely on observation. Because the earth's atmosphere is opaque to ultraviolet rays, X rays and gamma rays, many methods and means of space exploration have appeared one after another, such as balloons, rockets, artificial satellites and spaceships.

Astronomical theory is often due to the lack of observation information, and astronomers often put forward many hypotheses to explain some astronomical phenomena. Then, according to the new observation results, the original theory is revised or replaced by a new theory. This is also where astronomy is different from many other natural sciences.