The most attractive object in the universe is the black hole. Black holes are also a favorite of science fiction themes, and the movie "Interstellar" is one of them. Black holes have been a mystery until 2019, and scientists have been in the middle of theoretical calculations, without a real hammer.
On April 10, 2019, a first-of-its-kind photo of a black hole caused a sensation as direct evidence of the existence of a black hole! Coincides with the theories of scientists. Scientists have a really good IQ, and they can find what they can find.
<h1 class="pgc-h-arrow-right" data-track="3" > Newtonian mechanics "dark star"</h1>
Black hole-like thinking can be traced back to the end of the 18th century, when there was no relativity or quantum mechanics! Newtonian mechanics is king.
Isaac Newton (1643-1727), who discovered the law of gravitation, argued that light is not a wave but a particle. British scientist John Michell (1724-1793) thought according to the old man's idea that if light is a particle, then it should be attracted by the gravitational attraction of celestial bodies and gathered. In this case, will there be a very large celestial body with a particularly large gravitational pull, so large that the light cannot escape after being attracted? Michelle further speculated that objects with super gravitational pull that made it impossible for light to escape from it must be black because there was no light emitted. Michelle gave such a celestial body a name: the dark star. In 1783, Michel published the theoretical thinking on dark stars in the form of a paper in the newspaper of the British Royal Society, but the definition of dark stars at that time did not have the wonderful properties of the current black hole, simply referring to visual dark objects, which can only be said to be similar to black holes, but it is already the feeling of the predecessor of black holes.
<h1 class="pgc-h-arrow-right" data-track="57" > general relativity black hole</h1>
The theory of relativity advocated by Albert Einstein (1879-1955) argues that the principle of invariance of the speed of light is fundamental, regardless of the inertial frame in which the speed of light is constant. General relativity also proposes the idea that gravity distorts space-time.
The dark stars speculated by Newtonian mechanics can be understood under the theory of general relativity as a region of space-time that has been extremely distorted, and its properties have become wonderful and renamed: black holes.
The basic equation of general relativity is the famous Einstein equation, this equation is very complex, it is difficult to come up with an accurate solution, the German physicist Karl Schwarzschild (1873-1916), a month after the publication of Einstein's general theory of general relativity, in December 1915, Schwarzschild used bold assumptions to solve the problem, calculating the precise solution of Einstein's field equation: the Schwarzschild solution. He hypothesized a stationary, regularly spherical star whose mass was concentrated at a point in the center: gravitational singularity, with a vacuum on the outside. Within a certain radius of gravity singularity matter, energy (including light) are imprisoned in it, and from the outside, this star is an absolutely dark being, that is, a black hole. This radius is called the Schwarzschild radius, and the sphere of this radius is called the event horizon.
Not only is space distorted near a black hole, but time is also distorted. The passage of time of people near the black hole slows down, and the passage of time of people in the event horizon position slows down infinitely.
< h1 class="pgc-h-arrow-right" data-track="70" > the history of black hole observations</h1>
With the theory of black holes, scientists have to find evidence of the theory in observations. With the observation, the probability of the real existence of the black hole gradually increased, and now it is a real hammer, which is real.
1. A powerful candidate for the discovery of black holes in 1964
In 1964 , a mysterious object radiating X-rays was discovered in the direction of Cygnus : Cygnus X-1.
Analysis of X-ray radiation shows that Cygni X-1 is a binary star. There is a blue supergiant star, and a suspected black hole, and X-1 Cygnus is a binary star formed by the interaction of the gravitational forces of these two objects.
It is suspected that the mass of the black hole is about 20 times the mass of the Sun, and the mass of the blue supergiant star is also about 20-40 times the mass of the Sun. The object suspected to be the black hole sucks up gaseous material from the blue supergiant star, and a large amount of gaseous matter is accelerated by gravity to orbit it at a super high speed, and the frictional heat between the materials causes the temperature to rise sharply, forming a disk similar to the Nezha hot wheel: the accretion disk. The blue supergiant cannot emit the observed X-rays by itself, which are emitted by the accretion disk.
So far, after long-term observations of Cygnus X-1 by a number of observation instruments, Cygnus X-1 is classified as a binary star system of microquasars, that is, it is basically certain that one of the celestial bodies is a black hole.
2. The body of the quasar
The above-mentioned Cygnus X-1 is classified as a binary system of microquasars, and what is a microquasar? Microquasars are small quasars.
In the 1960s, strange celestial bodies of extraordinary brightness were observed, somewhat like stars and a bit like nebulae, emitting electrical radiation such as galaxies and not galaxies, why there were such celestial bodies at that time astronomy could not explain, titled quasars.
Referring to the later theory of the accretion disk formed around the black hole in Cygnus X-1, scientists gave an active galactic nucleus (AGN) model, believing that the quasar is a high-luminosity active galactic nucleus at a very distant distance, with an extramassive black hole at the core, and the black hole is surrounded by dust, gas and a part of stellar material, rotating at high speed due to super gravitational force, forming a huge accretion disk. Near the event horizon of the black hole, the inside of the accretion disk, matter falls into the black hole and radiates energy. Therefore, quasars are also called quasar power supplies.
The quasar's body is actually the black hole and its accretion disk, which is a young, active galactic nucleus. Quasars will evolve into ordinary spiral and elliptical galaxies. There is a consensus in the scientific community.
The Milky Way must not have quasars, it is too dangerous. Microquasars can still exist, and Cygnus X-1 is in the Milky Way.
3. The first simulated map of a black hole
Jean-Pierre Luminet (b. 1951), French cosmo physicist Jean-Pierre Luminet (b. 1951),
With his mathematical expertise and related techniques, he simulated for the first time what a black hole would look like. Using data returned from a 60s IBM 7040 punch computer, Luminière hand-drew a simulation of a black hole. The simulation map perfectly captures the shape of the accretion disk near the black hole.
4. For the first time, humans directly observe black holes
On April 10, 2019, the Event Horizon telescope (eht) directly photographed a giant black hole. The subject is a huge black hole at the center of the elliptical galaxy M87. The imagery obtained from the shooting data shows the shadow of the black hole itself. Became conclusive evidence of the existence of a massive black hole at the center of M87.
Even with event horizon telescopes with resolutions equivalent to millions of human vision, shooting the M87 galaxy about 55 million light-years away from the solar system, images of black holes are still a bit blurry. In order to better interpret the image of the black hole in the M87 galaxy, NASA had to make a higher resolution simulation map, and the accretion disk shape of the simulation map was very clear.
Originally, M87's accretion disk should theoretically be a horizontally rotating disc, but NASA's simulation map has a luminous arch shape above and below, and the two glowing arch shapes are caused by the accretion disk on the back of the black hole. The light emitted by the accretion disk on the back of the black hole is bent upward and downward by the black hole's strong gravitational pull to the front, and the accretion disk on the back can also be seen from the front. This is strikingly consistent with the first simulated map of a black hole in 1978. The most happy person to be most happy about direct photographic black hole imaging should be Luminiere.
The accretion disk behind the black hole in the above NASA black hole simulation diagram can be observed above and below, and the left side of the accretion disk close to the observer's side looks bright in the Doppler effect, which is a good representation of the black hole's characteristics.
<h1 class="pgc-h-arrow-right" data-track="97" > summary</h1>
There are many black holes in the Milky Way that have yet to be discovered and studied by humans.
The black hole at the center of the Milky Way is supposedly only one-thousandth of the black hole in the M87 galaxy.
The M87 galaxy has a black hole mass of about 6.4 billion times that of the Sun and a volume of 6.8 million times that of the Sun.
The black hole at the center of the Milky Way has a mass of about 4.3 million times the mass of the Sun and a volume of about 2700 times that of the Sun.
Although there are still many imaginative components in the above scientific research achievements, the imagination of scientists throughout the ages is the key to opening the door to truth.
The research results of black holes have always been the focus of attention of the whole world, and Martian colonization is in full swing, and I hope that you will learn more about black holes and prepare for Mars.