The larger the mass of a star, the shorter it is "ordered". According to cosmological models, in the early universe, the mass of stars was generally very large. Considering that the birth of Milky Way can be traced back to about 13 billion years ago, it is not difficult to infer that after such a long time, there should be huge black holes in the Milky Way today.
Then the question is, how far is the black hole closest to the earth from us? In fact, as the observation level continues to improve, the record of "the closest black hole to the earth" is also constantly refreshing, and it looks like a black hole is getting closer and closer to us.
On November 4, 2022, a research team composed of astronomers from the "Harvard-Smithsonian Astrophysics Center" and the "Planck Institute" published a paper in the "Monthly Journal of the Royal Astronomical Society" that astronomers have discovered the closest black hole to the earth so far, let's see what's going on.
black holes are impossible to directly observe. This is because under the constraints of the strong gravity of the black hole, even light cannot escape from the black hole, so we can only make indirect observations through some cosmic-level phenomena triggered by black holes. For example, we can indirectly infer the existence of black holes by observing the impact of black hole gravity on the trajectory of stars.
In fact, this method was adopted by the research team. During the research work, the team's astronomers analyzed the motion trajectory data of 168,065 stars sent back by the Gaia satellite, and finally discovered a star that was obviously affected by the gravity of the black hole.
(Note: The Gaia satellite was launched in 2013 and is mainly committed to observing the positions, distances and movements of stars in the Milky Way. The number of stars can reach 1 billion)
This star is an yellow dwarf star similar to the sun. It is located in Ophiuchus in the sky, about 1,560 light years from the earth. Researchers found that the star moves around a "point" along an elliptical orbit. According to its motion speed, and the size and period of the motion orbit, this "point" is actually its common center of mass with another celestial body, and the mass of the "another celestial body" can reach sun mass 410 times.
More importantly, this celestial body is "dark", which means that there is no observable celestial body in the area where it is located. Based on this, the researchers believe that this celestial body should be a dormant black hole and named it "Gaia BH1".
To further verify this view, the researchers analyzed a large number of data from multiple observation equipment such as "Keck Telescope", "MPG/ESO Telescope", "Very Large Telescope", and "Gemini Telescope". The results were all: in the area where this celestial body is located, nothing can be seen. This means that the black hole "Gaia BH1" does exist, and it has become the closest black hole to Earth discovered by astronomers so far.
It is worth mentioning that observation data shows that the distance between "Gaia BH1" and its companion star is very close, only 1 astronomical unit , which is equivalent to the average distance between the sun and the earth. Astronomers speculate that it is impossible to naturally form such an binary star system at such a close distance. Therefore, one of the most likely situations is: in the past days, "Gaia BH1" captured a "passing" star through its own gravity.
researchers pointed out that theoretically, the number of black holes in the Milky Way can reach 100 million, while we have discovered only a few dozen black holes. The reason for this is that our observation ability needs to be improved, another important reason is that our observation data is not rich enough.
At present, the research team is preparing to analyze updated and more observational data from the "Gaia Satellite". According to researchers' estimates, dozens of black holes hidden deep in the universe should be found in subsequent research, and the record of "the closest black hole to the earth" may be refreshed again.
OK, let’s stop here today. Welcome to follow us and see you next time.
(Some of the pictures in this article are from the Internet. If there is any infringement, please contact the author to delete it)
Reference materials:
Kareem El-Badry et al, A Sun-like star orbiting a black hole. Monthly Notices of the Royal Astronomical Society, stac3140
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-