In which constellation does the earth look at the center of the Milky Way?

Do you know that there is a Sagittarius A* A* in the center of the Milky Way, which is 10 trillion kilometers away from the earth? Since American astronomers proposed that "there is a supermassive black hole in the center of the Milky Way where the solar system is located",

For more than 30 years, astronomers all over the world have been skeptical about this. Yesterday, the Shanghai Astronomical Observatory of Chinese Academy of Sciences announced that the international astronomical research team headed by its Shen Zhiqiang researcher, after eight years of research, found evidence of supermassive black holes around Sagittarius A** in the center of the Milky Way, which is the most convincing evidence so far.

This research result was published in the British magazine Nature Today.

Shen Zhiqiang said that the "conclusive evidence" they found was the measurement of the size of Sagittarius A* A* in the center of the Milky Way. Scientists explain their "process" of obtaining evidence like this:

A century ago, the concept of black hole was put forward, and countless astronomers made unremitting exploration and found many black hole "candidates". 1974 In February, scientists discovered that Sagittarius A* with mysterious radio emission source was a supermassive black hole. Because it is closest to the earth, it is recognized as the best target for studying black hole objects. Starting from 1997, Shen Zhiqiang and his team "locked" the "darkest" celestial body-Sagittarius A*.

After three years of preparation and two years of waiting, scientists began to approach the veil hanging over Sagittarius A*. Scientists used the world's most advanced VLBA telescope to observe and study Sagittarius A*, and finally successfully photographed the first image of Sagittarius A* at the wavelength of 3.5 mm (a working wavelength) in 20021October 3 165438+. Then, after three years of calculation and repeated argumentation, scientists determined that the true diameter of this mysterious radio transmitter is equivalent to the radius of the earth's orbit. In other words, this Sagittarius A*, which is at least 400,000 times larger than the mass of the sun, occupies an area of only 65.438+0.5 billion kilometers. Knowing the diameter of Sagittarius A* will know its volume, and the ratio of mass to volume is the density of celestial bodies. It is inferred that the minimum density of Sagittarius A* is more than one trillion times larger than any known black hole candidate, which strongly supports Sagittarius. In other words, the density of Sagittarius A* excludes the possibility that it is not a black hole. What's more exciting is that this is the first time that scientists have seen an area so close to the center of a black hole.