The concept that objects may exist in the universe can be traced back to the late 18th century. The surface gravity of the universe is so great that even light can escape from them.Clergy and prolific scientists in different ways John Mitchell In 1784, the famous mathematician Pierre Simon Laplace In 1796, they realized that a very dense and large enough star might create a gravitational field on its surface, so the escape velocity (the minimum speed at which any object must leave the field) would exceed the speed of light, and the speed of light would not escape both. . These corpses will be truly black.
In the 20th century, these mathematical considerations Einstein’s General Theory of Relativity, Describing the gravitational field as a theory of space-time distortion.In her Karl Schwarzschild A model was developed in 1916 that described a non-rotating black hole.
But this is Roger Penrose, Is one of the three winners of the 2020 Nobel Prize in Physics. He proved in 1956 that black holes are the direct result of general relativity, which is the result of the gravitational collapse of massive objects. Penrose pointed out that under very common conditions, gravity falls will form a “trapped surface” from which there is no escape.
In the second half of the 20th century, observational evidence of black holes appeared. The existence of quasars is a generator of large amounts of energy produced by matter falling from huge black holes, and has always been one of the pillars of evidence for the existence of black holes.
In 2019, the project Horizon Telescope Managed to obtain the first image of a huge black hole in the center of the Milky Way M87. In this image, the shadow of the black hole 6.5 billion times the mass of the sun can be accurately seen.
The stars guide Genzel and Ghez towards Sgr One kind*
In terms of the work of the other two winner groups, Reinhard Genzel (MPE-Germany) and Andrea Ghez (University of California, Los Angeles) Focus on carefully observing what the surrounding space-time is like. It surrounds a black hole of 4 million suns (called Sagittarius A*o). Sgr A *) Located in the center of the Milky Way.
In fact, this year’s Nobel Prize in Physics was awarded for discovering that Sgr A* is a black hole, and they managed to prove it through years of hard work. Orbits of stars around him.
The central part of the Milky Way galaxy was observed in the near infrared with the NACO instrument on the Very Large Telescope. By tracking the motion of the star closest to the center for more than 16 years, astronomers were able to determine the mass of the supermassive black hole in it. / Those ones. Gillessen et al.
One of them, usually called Star S2, Complete an orbit every 16 years, and complete 3% of the speed of light at the location closest to the black hole (the last time in May 2018). Sgr A* formed a dream laboratory to verify the predictions of general relativity near a huge black hole.
The challenges these teams face in implementing these measures are extraordinary.inside that (European Southern Hemisphere Astronomical Research Organization) 30 years of cooperation And support the Genzel team.
Avoid the ambiguity of our atmosphere
His observation of Sgr A* was carried out in Chile’s ESO telescope, first in New Technology Telescope (NTT) In La Silla, and the last 20 years Very Large Telescope (VLT) And the interferometer (VLTI) in Paranal. The main challenge in being able to measure the position and velocity of stars orbiting Sgr A* like S2 is to avoid blurring caused by the Earth’s atmosphere.
In this case, Genzel’s team developed a speckle camera for NTT to track the positions of these stars.Later, musical instruments what for ÿ SINFONI They rely on a technology called adaptive optics (also used in ophthalmology and tissue imaging) to correct the harmful effects of atmospheric turbulence in real time and accurately measure the speed of these stars near Sgr A*.
The latest technological miracle developed by the Genzel team and other centers such as ESO is called gravity, This is an interferometer that interferometers the light of Paranal’s four 8-meter telescopes and uses adaptive optics.
Professor Reinhard Genzel (MPE Garching) of the Deputy Observatory. / That
At ESO, we decided that using these instruments to observe the star S2 in the closest way to Sgr A* in 2018 is the top priority of science. New detectors must be developed to reduce the vibration of the VLTI platform by a factor of 10, and many infrastructures of the Paranal Observatory must be refurbished to facilitate these observations. These are the top priorities.
The rewards of science have reached the greatest effort: Genzel’s team not only contributed to the discovery of the huge black hole Sgr A*, but also successfully quantitatively measured two predictions of general relativity: Gravitational redshift It rotates at the speed of the star S2 and is closer than the orbital rotation or “precession” of S2. They are important scientific trophies on the subject of black holes, and they continue to attract everyone’s attention.
Roger Penrose and Andrea Ghez. /Sync/MacArthur Foundation
Xavier Barcons It’s him managing Director European Southern Observatory (ESO).