Black holes are extremely dense objects in space, and even light cannot escape from them
While black holes are mysterious and bizarre, they are also a key result of gravitational action:
When a large amount of mass is compressed into a small enough space, the resulting energy tears apart the structure of space-time and becomes a so-called singularity
The black hole's gravitational pull is so strong that it is able to suck in nearby matter and "eat" it
Here are 10 things you might want to know about black holes:
In the composite image above, galaxy NGC 1068 appears in visible light and X-rays High-energy X-rays (magenta) captured by NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) are superimposed on visible light images from NASA's Hubble Space Telescope and Sloan Digital Sky Survey X-rays come from an active supermassive black hole at the center of the galaxy, also known as a quasar. This supermassive black hole has been studied more because of its relative proximity to our Milky Way
No type of light, including X-rays, escapes from the black hole's gravitational range and cannot return as long as it enters the region
NASA's telescopes that study black holes are looking at the environment around the black hole, where the material is very close to the black hole's gravitational range
When something is pulled into a black hole, it is heated to millions of degrees, so it emits X-rays
The enormous gravitational pull of a black hole can also distort space itself, so the effects of invisible gravity on stars and other objects can be seen
In 2015, researchers discovered a black hole called CID-947, which is growing much faster than its host galaxy
The black hole at the center of the Milky Way is almost 7 billion times the mass of the Sun and is one of the most massive black holes ever discovered
However, the mass of the Milky Way's black holes is thought to be normal. Because the light around it must travel long distances, scientists have been observing the universe for less than 2 billion years, while the observed black hole is only about 14 percent of its current actual age (nearly 14 billion years have passed since the Big Bang).
After a massive star collapses, a stellar-mass black hole may form in a matter of seconds with a mass tens of times that of the Sun. These relatively small black holes could also be formed by merging the remains of two dense stars, known as neutron stars. Neutron stars can also merge with black holes to form a larger black hole, or two black holes can collide. Mergers like these would also quickly form black holes and create ripples in space-time called gravitational waves
Even more mysterious is the massive black hole found at the center of the galaxy, the "supermassive" black hole, which can reach millions or billions of times the mass of the Sun. It could reach a very large scale in more than a billion years, but it's unclear how long it will take for a black hole to grow to that extent
The scientists used the horizon telescope to observe the center of the M87 galaxy to obtain the first image of the black hole, as shown in the figure. The image shows a bright ring with a mass 6.5 billion times that of our sun due to the strong gravitational pull around the black hole that bends the light
The study involves observing the motion of stars at the center of galaxies. These motions imply a dark, massive object whose mass can be calculated from the speed of the star. The material that falls into the black hole increases the mass of the black hole. Its gravitational pull does not disappear from the universe
The above imaginary diagram illustrates the activity surrounding the black hole. While it is impossible to see the material that passes through the black hole's gravitational range, the material that rotates outside this threshold is accelerated to millions of degrees and produces intense X-ray radiation
No. A black hole can't possibly eat an entire galaxy. The gravitational range of a supermassive black hole in the middle of the Milky Way is large, but not enough to swallow the entire galaxy
This illustration shows the flow of luminous material that a star produces as it is destroyed by its own destruction when it is swallowed up by a supermassive black hole. The black hole is surrounded by a circle of dust. When a star is close enough to be swallowed up by a black hole, the stellar material is stretched and compressed as it is inhaled, releasing a large amount of energy
Definitely not going to be good! But our understanding of the interior of black holes is basically limited to Einstein's general theory of relativity
For black holes, distant observers can only see regions outside their gravitational range, but individual observers who fall into the black hole will experience a completely different "reality." If you get into the gravitational range of a black hole, your perception of space and time will change completely. At the same time, the huge gravitational pull of the black hole will compress you horizontally like a ramen noodle, stretching you vertically
Fortunately, this never happened to anyone — black holes are too far away from our solar system to absorb anything from our solar system. But scientists have observed black holes tearing stars apart, a process that releases vast amounts of energy
NASA's Chandra X-ray Observatory detected exaggerated velocities from disks around the black hole. The artist's impression shows how the strong gravitational pull of the black hole on the left pulls gas away from the companion star on the right. This gas forms a disk of hot gas around the black hole, and the wind leaves the disk at 20 million miles per hour, about 3 percent of the speed of light.
Our sun will never become a black hole because it is not massive enough to explode. Instead, the Sun will turn into a dense remnant of a star called a white dwarf
But suppose the Sun suddenly becomes a black hole with the same mass as it does today, which won't affect the planet's orbit because its gravitational impact on the solar system is the same
As a result, Earth will continue to orbit the sun's shifting black hole without being drawn — though the lack of sunlight would be catastrophic for life on Earth
The central region of our Galaxy contains a series of bizarre objects, including a supermassive black hole called Sagittarius A, which has a mass of about 4 million times the mass of the Sun and a temperature of up to millions of degrees, with clouds of gas, neutron stars and white dwarfs rapidly rotating around its perimeter. The situation around Sagittarius A is shown in this composite image, where chandra data (green and blue) combined with radio data from the MeerKAT telescope in South Africa (red) will eventually become the data portion of the Square Kilometre Array (SKA).
When a massive star explodes, it leaves a stellar-mass black hole behind
These explosions disperse elements such as carbon, nitrogen and oxygen, which are essential for life, into space
The merger between two neutron stars, two black holes, or a neutron star and a black hole will likewise scatter heavy elements around them and could one day become part of a new planet
Shock waves from stellar explosions could also trigger the formation of new stars and new solar systems. So, in a sense, the creation of our planet owes its origin to the explosions and collisions of black holes long ago
On a larger scale, most galaxies appear to have supermassive black holes at their centers. The connection between the formation of these supermassive black holes and the formation of galaxies is unclear. It is possible that black holes played a role in the formation of our milky way. But the question of chicken or egg first — that is, which one appears first, the Milky Way or the black hole? - It is a big problem in our universe
The artist's paintings show the most distant supermassive black hole ever discovered. It was part of a quasar that was only 690 million years old after the Big Bang
The most distant black hole ever detected is in a galaxy about 13.1 billion light-years from Earth
This supermassive black hole is called a "quasar" by astronomers, and a huge amount of gas is pouring into the black hole at such a fast speed that its energy output is a thousand times that of the galaxy itself. Its extreme brightness is why astronomers can detect it at such a distance
The central region of the image contains the most concentrated supermassive black hole ever recorded, with about 1 billion in the entire sky This 2017 image, made from more than 7 million seconds of Chandra observation time, provides astronomers with its X-ray telescope's observations of the early universe, providing astronomers with how black holes grew over the billions of years that began shortly after the Big Bang In this image, the low-energy, medium-energy, and high-energy X-rays detected by Chandra are shown as red, green, and blue, respectively
The universe is a big place. In particular, the size of the gravitationally affected regions of a particular black hole is very limited compared to the size of galaxies
This even applies to the supermassive black hole found in the middle of the Milky Way. This black hole may have "eaten" most or all of the stars that formed nearby, while more distant stars are mostly not sucked in
Since the mass of this black hole is already millions of times the mass of the Sun, even if it swallows more Sun-like stars, its mass will only increase slightly
Earth (26,000 light-years away from the Milky Way's black hole) is not in danger of being pulled in
Future galactic collisions will cause black holes to increase in size, for example by merging two black holes. But collisions don't happen indefinitely, because the universe is large and expanding, so any form of black hole runaway effect is unlikely to happen
In this illustration of the black hole and its surrounding disks, gas circling toward the black hole accumulates outside the black hole, causing traffic jams. For smaller black holes, traffic congestion is closer, so the resulting X-rays have a shorter emission time
yes. The late physicist Stephen Hawking proposed that while black holes get larger by eating matter, they also slowly shrink because they are losing trace amounts of energy called "Hawking radiation."
Hawking radiation occurs because empty space or vacuum is not really empty
It is actually an ocean of particles that are constantly appearing and disappearing. Hawking showed that if a pair of such particles were produced near the black hole, one of them could be pulled into the black hole before it was destroyed. In this case, its partner will escape into space. The energy comes from the black hole, so the black hole slowly loses energy and mass through this process.
Theoretically, black holes would eventually evaporate through Hawking radiation. But for most black holes we know of, the time to evaporate is much longer than the age of the entire universe. Black holes, even those several times the mass of the Sun, can exist for a long time
Resources:
1、、NASA
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