black holes
By their very nature, black holes are black. This is the first image of a black hole since April 2019. Light forms a bright circle that rotates around a black hole under intense gravity, which is 6.5 billion times wider than our Sun. This black hole is at the center of the galaxy M87, 55 million light years from Earth. Photo courtesy of Event Horizon Telescope.
What are black holes?
Black holes have such strong gravity that nothing, not even light, can escape them. That's why black holes are black. We cannot see them directly. But we can see how black holes affect the space around them. Black holes can be as large as millions or billions of stars. Or they could be as small as a few stellar masses that are crushed at high densities during supernova explosions. And last year we learned that there are intermediate mass black holes. In addition, there may be micro-black holes.
2022 lunar calendars are still available. Place your order before they leave!
Sponsored by Chegg StudyⓇ
Study time, crunch time, anytime.
Get access to over 55 million textbook solutions and phased walkthroughs in addition to expert quizzes.
learn more
From theory to reality
In his general theory of relativity since 1915, Albert Einstein was the first to suggest that our universe consists of such strange, dense, massive objects. As a natural consequence of massive star deaths and falls, black holes emerge from Einstein's general relativity equation. In 1916, German mathematician Carl Schwarzschild was the first to mathematically create black holes. Theoretical physicist John Wheeler first named the black hole many years later, in 1967.
Until the 1970s, black holes were only mathematical curiosity. Then, in 1971, scientists discovered the first physical black hole, the Cygnux X-1.
Stellar massive black holes
We know of three types of black holes. The first is the so-called stellar mass black hole. These are the remnants of huge stars. When, at the end of its life, a star about five times the mass of our Sun explodes as a supernova, gravity suddenly and violently compresses its center.
Depending on the mass of the star, it could stop falling and become a neutron star. But if its mass is sufficient, the core will continue to break, forming a black hole. Stellar mass black holes range from at least five times the mass of our Sun to about 60 times the mass of the Sun. They are usually between 10 and 30 miles (16-48 km) in diameter.
Artist's concept of Science X-1. Astronomers believe that Cygnus X-1 is a typical stellar black hole in the binary star system. Cygnus X-1 was once a star before falling into a black hole. The reason we can detect a black hole is that it is its companion, a blue supergiant variable star named HDE 226868. Image via ESA / Wikimedia Commons.
Medium black holes
Scientists have announced the discovery of a medium-sized black hole in 2021. This type of black hole bridges the gap between small, large star-shaped black holes and supermassive black holes hidden in the center of galaxies. The newly discovered "Gold Locks" black hole has a volume of 55,000 suns. Astronomers have discovered the middle black hole by locating something far behind it: a gamma-ray signal. The gravitational lens of the burst emission sent scientists into a medium-sized black hole.
Intermediate mass black holes, larger than those formed by individual stars - but smaller than the supermassive at the centers of galaxies - should theoretically exist. Astronomers say they have discovered a gamma-ray burst that has been lensed by a black hole in terms of gravity. In this diagram, the gamma ray burst is shown on the right. At the center, a large black hole is acting as a beam of light emitted by gamma rays. Photo by Carl Knox / Oz Grow / University of Melbourne.
Massive black holes
The third type of black hole is the supermassive black hole. They can contain billions of suns. Astronomers believe that most galaxies have large black holes at their centers. At the center of our own Milky Way galaxy, Sagittarius A *, is about 4 million times the mass of our Sun and has a diameter of about 37 million miles.
Another example of a supermassive black hole is in the center of the quasar called TON 618. Its central black hole is estimated to be 66 billion solar masses. Huge black holes could have formed from large collapsing clouds of interstellar hydrogen in the early history of the universe, although their origins are not clear and this is an area of very active research. They may also have accumulated extra mass on Evans by merging with other black holes.
The artist's imagination represents the atmosphere of a large black hole in the heart of many galaxies. The black hole is surrounded by a magnificent action disc of very hot, falling material and dusty torus (donut-shaped ring). Black hole poles often carry high-speed jets of material that can travel very long distances in space. Image via ESO / Wikimedia Commons.
The fourth type of black hole
There could be another type of black hole, a micro black hole. These stars will be smaller in size than black holes. So far, they are still fictitious, and no one's existence has been proven.
What's inside a black hole?
By definition, we cannot observe what is inside a black hole, because no light - no information of any kind - can escape. But astronomical theories suggest that, at the center of a black hole, the mass of all black holes is concentrated in a small point of infinite density. This point is known as unity.
This is the point - this uniformity - that creates the incredibly strong gravitational field of the black hole. Note, however, that uniformity does not exist. This is because all known physics breaks down in extreme conditions at the center of a black hole, where quantum effects undoubtedly play a large part. Since we do not yet have a quantum theory of gravity, it is impossible to say what is actually at the center of the black hole.
Black hole boundaries
The extent of the black hole is its event horizon. This is not a physical edge. It is just a point in space beyond which it is impossible to escape the gravity of the black hole. Once anything falling into a black hole passes through the horizon of the event, it can never leave the black hole again. It inevitably and inevitably pulls towards the center of the black hole. Within the event horizon, any solid object explodes under intense gravity and its component is reduced to subatomic particles. On the horizon of the event, the speed of escape of the black hole reaches the speed of light.
Observation of black holes
Without emissions from black holes, scientists can only observe the effects of their gravity on nearby objects in space. If there are stars or gases near the black hole, it is actively "feeding" them. That is, a black hole can pull material from nearby objects. In that case, there would be an action disk in the black hole. This is where the matter moves inward before the black hole eats it, like water in a drain. The action disk can rotate at a significant percentage of the speed of light: friction between the particles colliding in the disk raises its temperature to millions of degrees, which produces large amounts of X-rays which can be detected by special binoculars. Is.
In April 2019, the Event Horizon Telescope Project revealed for the first time a live image of a black hole, the supermassive black hole at the center of the giant elliptical galaxy M87. A global array of radio telescopes captured the image. This undoubtedly shows that there are black holes. Scientists were able to directly test the general relativity models of the black hole's behavior and found that the M87's black hole is very accurate.
Picture of the Hubble Space Telescope, a jet-powered jet from the center of the Galaxy M87. The jet consists of electrons and other subatomic particles that travel at approximately the speed of light. Photo by Hubble Heritage Team (STScI / AURA) / NASA / ESA / esahubble.org.
A black hole is an area of space in which the field of gravity is so strong that nothing, even light, can escape it. Black holes come in three sizes, possibly four.
No comments:
Post a Comment