Edwin P.Hubble, an American astronomer, is one of the most famous people who study the theory of modern universe and the founder of extragalactic astronomy. He discovered the existence of extragalactic galaxies and the expansion of the universe. He was the founder of extragalactic astronomy and the first person to provide evidence of the expansion of the universe.
When studying at the University of Chicago, Hubble was inspired by astronomer Haier and became interested in astronomy. But after graduation, I went to Oxford University to study law, and 19 13 began to work as a lawyer in Kentucky, USA. Later, he finally concentrated on astronomy and returned to the University of Chicago to work at the Yerkes Observatory in Wisconsin. After receiving a doctorate in astronomy and joining the army, he began to concentrate on studying extragalactic galaxies at Wilson Observatory (now Haier Observatory) and made new discoveries. In the 1920s, there was a great discussion in astronomy about whether galaxies were part of the Milky Way. During the period of 1922 ~ 1924, he found that not all nebulae were in the Milky Way. After analyzing the brightness of a number of Cepheid variables, Hubble concluded that these Cepheid variables and their nebulae are hundreds of thousands of light-years away from us, so they must be outside the Milky Way. This discovery, published in 1924, forced astronomers to change their views on the universe.
1925, when he classified the galaxies outside the river according to their shapes, Hubble came to a second important conclusion: galaxies seem to be moving away from us, and the farther away they are, the higher the speed of moving away. This conclusion has far-reaching significance. Astronomers have always thought that the universe is static, but now it is found that the universe is expanding. More importantly, Hubble also found that the expansion rate of the universe is constant in 1929. This rate is called Hubble constant, which is the ratio of the speed and distance of galaxies. Later, after theoretical research by other astronomers, the universe has expanded at a constant rate of10 ~ 20 billion years.
At the beginning of the 20th century, most astronomers thought that the universe would not expand beyond the Milky Way. But in the early 1920s, when Hubble observed the mysterious Andromeda with the largest telescope at that time, he found that the nebula in Andromeda was not the gas of the Milky Way, but a completely independent galaxy. There are many other galaxies outside the Milky Way, and the universe is much bigger than people think.
Hubble Space Telescope
Hubble Space Telescope (abbreviated as HST) is a telescope orbiting the earth in the name of astronomer Hubble. Its position is above the earth's atmosphere, so it has the advantages that ground-based telescopes do not have-the image will not be disturbed by atmospheric turbulence, the visibility is excellent, and there is no background light caused by atmospheric scattering. It can also observe ultraviolet rays absorbed by the ozone layer. It became the most important instrument in the history of astronomy after it was launched in 1990. It fills the gap in ground observation, helps astronomers solve many basic problems and gain more understanding of astrophysics. Hubble's ultra-deep field of view is the deepest (most sensitive) optical image obtained by astronomers.
From his initial conception in 1946 to the launch, the plan to build a space telescope has been postponed continuously and is plagued by budget problems. Immediately after launching, he found that there was spherical aberration in the main mirror, which seriously reduced the observation ability of the telescope. Fortunately, after 1993 completed the maintenance task, the telescope returned to the planned quality. It has become the most important tool for astronomical research and publicity of public relations. Hubble Space Telescope, Compton Gamma-ray Observatory, Chandra X-ray Observatory and Spitzer Space Telescope are all part of NASA's Large Orbit Observatory program. The Hubble Space Telescope is jointly managed by NASA and the European Southern Observatory.
Hubble's future depends on the success of subsequent maintenance tasks. Several stable gyroscopes have been damaged. At present (2007), even the spare ones have been used up, and the function of the other pointing telescope is also declining. Gyroscope must be repaired manually. On June 30th, 2007, the main advanced sky camera (ACS) also stopped working. Before manual maintenance, only ultraviolet channels can be used. On the other hand, if there is no further elevation angle to increase the orbital height, the resistance will force the telescope to re-enter the atmosphere at 20 10. Since the unfortunate incident of the space shuttle Columbia in 2003, astronauts lack safe haven in an emergency because the International Space Station and Hubble are not at the same height. Therefore, NASA believes that it is unreasonable and dangerous to repair Hubble Space Telescope by manned space mission. After a new review, Mike Griffin, CEO of NASA, decided to carry out the last Habai maintenance mission in Atlanta on June 3 1 2006, and the mission is scheduled for September1KLOC-0/2008. For safety reasons, Discovery will be on standby at LC-39B launch pad to provide rescue in case of emergency. The planned maintenance will enable the Hubble Space Telescope to work continuously until 20 13. If it is successful, the subsequent James Webb Space Telescope (JWST) should have been launched and can be connected to the mission. Weber Space Telescope has far more functions than Haber in many research projects, but it only observes infrared rays, so it will be in the spectrum.
Hubble distinguishes galaxies according to their structures, and Hubble's classification of galaxies is still used in astronomy.
Hubble won many honorary titles and medals for his contribution to astronomy. His works include Red Shift of Nebula Spectrum and Atlas of Hubble Galaxy.