How scientists estimate that the farthest galaxy from us is 15 billion to 20 billion light years?

The state awarded the "Two Bombs and One Satellite" Meritorious Service Medal to 23 scientists who have made outstanding contributions to the development of the "Two Bombs and One Satellite," and 14 of them have studied or worked at Tsinghua University. They are: Wang Ganchang, Zhao Jiuzhang, Qian Xuesen, Peng Huanwu, Qian Sanqiang, Wang Daheng, Chen Fangyun, Guo Yonghuai, Tu Shouyi, Yang Jiaqi, Wang Xiji, Deng Jiaxian, Zhu Guangya, Zhou Guangzhao.

There are also a group of alumni of our university who have made outstanding contributions to China's nuclear cause, such as Academician Huang Zuqia and Academician Tang Xiaowei. At the Xinjiang nuclear test base, five of the more than a dozen commanders are scientific and technological personnel, and three of them are Tsinghua alumni. Among the 11 directors of the Northwest Institute of Nuclear Technology, which is affiliated to the base, 8 are scientific and technological personnel, and 5 of them are Tsinghua alumni.

Among the thousands of scientific and technological workers who have silently dedicated themselves to the cause of the motherland's "two bombs and one satellite," there are thousands of Tsinghua alumni. Twenty-seven alumni participated in the first nuclear test site work and laboratory mission in 1964 at the Northwest Nuclear Test Base. Teachers from many faculties of our university have also contributed to the success of the "Two Bombs and One Satellite".

Today, at the moment of commemorating the 40th anniversary of China's first atomic bomb, we would like to pay high tribute to all the predecessors who have contributed to the cause of "two bombs and one satellite"!

With a laser or with some rays. of these.

This one... I'm sorry... I'm a second-hand scientist... What makes sense!

The following ** has been said, you can take a look.

The author - a small article.

Light is the fastest speed in the universe, it can travel up to 300,000 kilometers per second in a vacuum, but in the vast universe, the speed of light is not that fast.

Taking the observable universe as an example, this is the largest range of the universe that has been measured by human beings, and its radius has reached 46.5 billion light years, which also means that it will take at least 40 billion years for light to cover this distance.

A light year is the distance of light propagating in a vacuum for a year, one light year is equal to 9,460.5 billion kilometers, reaching the level of light years, and the light it emits takes a long time to reach the earth, which is why the number of stars in the universe is so large, but it is difficult for scientists to observe them.

The farthest galaxy discovered so far is the GN-Z11 galaxy, about 13.4 billion light-years away from Earth, which is still in its infancy but is growing at an astonishing rate.

The GN-Z11 galaxy, jointly announced by NASA and the European Space Agency, is also the farthest galaxy ever discovered from Earth.

It is understood that GN-Z11 is located near the constellation Ursa Major, and according to the calculation results, the appearance of GN-Z11 that people see now is the light it emitted when the universe was **400 million years old.

The discovery of GN-Z11 broke the record of all galaxies ever discovered, and, because GN-Z11 was unusually bright, it was successfully captured by the Hubble Telescope.

In the face of tens of billions of light-years of stars, humans can currently only judge the distance of galaxies by the degree of redshift, and before GN-Z11, egsy8p7 was considered the farthest galaxy from Earth, and its redshift was, while GN-Z11 was.

Although GN-Z11 is still in its infancy, it is only 25 times the size of the Milky Way, but it is growing more than 20 times faster than the Milky Way, which means that in the future, GN-Z11 will overtake the Milky Way and become one of the supergalaxies in the universe.

However, the discovery of GN-Z11 has also left scientists with a lot of mystery, and it stands to reason that the first star born in the GN-Z11 galaxy only appeared about 2 to 300 million years ago, so its growth rate will be limited.

At present, the speed of GN-Z11 surpasses that of any baby galaxy discovered by humans in the past, and while curious about the secret of its growth, it also makes people wonder if the true age of other stars in the universe is wrong, or is the age of the universe really only 13.7 billion years old? I am afraid that this question has not yet been answered.