In that year it was still believed that it was possible that the entire universe would eventually collapse under its weight. All the stars that remain, all the stars that go away and all the black holes will merge into one cosmic contraction known as the Great Ingestion. If this scenario is true, then the entire universe will find its end inside a single giant black hole
Article by Paul Davis, January 1994.
At the center of our galaxy, the Milky Way, lurk dark and ominous monsters that swallow anything that approaches them. The evidence for this comes from new photographs, taken at the Steward Observatory in Arizona, which revealed a compact cluster of stars being pulled with intense force by a massive invisible object.
Astronomers began to discover similar processes in the centers of other galaxies as well. They suspected that these were black guys. Among the scariest objects in the universe. They have such strong attraction fields that everything that approaches them is drawn into them. Not even the light can escape them and therefore they are dark.
Until a few years ago, many people thought that black holes were the stuff of science fiction. Now, following new observations made by astronomers in Edinburgh, it has become clear that not only do they exist, but that the universe is full of them.
Their 20-year-old study of quasars - distant, compact and very bright star-like objects - showed that there are a large number of cosmic objects, each with a mass similar to the planet Jupiter. If they are, as the University of Edinburgh team claims, they are species of black holes and could explain one of the biggest mysteries of the universe.
For years, cosmologists claimed that at least 90 percent of the universe must be composed of "dark matter", but until now no one could find out what the nature of the disappeared matter was. Now, these astronomers say, the answer is black holes.
With all the current excitement, it's hard to believe that only 20 years ago black holes were barely a theoretical idea. It was in the 20s when a satellite launched to discover sources of X-rays in deep space found a powerful source within the Cygnus system. The astronomers suspected that the X-rays came from a binary star system containing a black hole. Since then, astronomers have discovered evidence of the existence of many other black holes.
These strange bodies were predicted by Einstein's theory of relativity, which describes space, time and gravity in terms of geometry. The mass of the objects distorts the geometry of space-time so that other objects are pushed towards them. It is possible to imagine such a compact object that endlessly interferes with space-time, producing a gravitational field so strong that even light - the fastest of anything known in the universe - cannot escape from it.
Since Isaac Newton and the 17th century it has been well known that if you throw an object into the air hard enough, it will escape the Earth's gravity. The critical escape velocity is 11 kilometers per second. If the Earth were compressed to half its current radius, without changing its mass, the escape velocity would increase to 15.6 kilometers per second. But if the mass of the Earth is compressed into the volume of a pea, the escape velocity will reach 300 thousand kilometers per second - the speed of light. Such a body will appear externally as black, because no light can escape from it. Compressing a larger object - for example a star larger than the sun - into a cubic kilometer will give the same effect.
During the 20s, American physicist Robert Oppenheimer concluded that when an aging star runs out of fuel to keep it burning, it will collapse under its own weight and compress into a fantastic density. In the years after World War II, astronomers discovered that large stars exploded in a phenomenon known as supernovae when they ran out of fuel. The explosion was caused by nuclear processes deep inside the star, which caused its core to compress. The process causes the release of energy that spreads to the outer parts of the star.
In 1967, Jacelyn Bell, a radio astronomer at the University of Cambridge, discovered some regular radio pulsations. The astronomers suspected that these were signs coming from the collapsing cores of a supernova. The material with a mass similar to the sun is compressed to a diameter of several kilometers. The weight caused the atoms to shatter and the formation of a ball of neutrons. These stars were called neutron stars. The gravitational force of neutron stars is so strong that it approaches the process of abducting light. The discovery hinted that even more massive stars - true black holes - may form within the supernova remnants.
In order for the neutron star not to collapse further, its neutron material must be very rigid. The more massive the star, the more rigid the material has to be, but there is a limit to this rigidity as well. No bone can be perfectly rigid. Calculations showed that the limit is reached at about ten The mass of the neutron star is about three solar masses.
Using the theory of gravity, the scientists followed the fate of a ball of stellar material that contained material in a larger than allowed amount. They predicted that it would take this sphere only a few microseconds to shrink into zero diameter and infinite compression, a state known as a singularity. The material of the star will effectively disappear from the universe - hence the name "black hole", coined by the astrophysicist John Wheeler (whom I later had the chance to meet when he came to visit Israel. AB)
Although the star is gone, its gravity remains, imprinting within the mark of space-time. These strong gravitational fields stop us from seeing the final stages of collapse. By trapping the light trying to escape. The only way to see what happens inside a black hole is to fall into one...
Being black, the black hole is difficult to detect. Astronomers rely on indirect evidence, such as the way the black hole's gravity pulls bright objects close to it. For example, many familiar stars are in a binary system, meaning a pair of stars orbiting each other. If one star collapses and becomes a black hole, the other star will continue to orbit it. If the two stars approach each other, the pull of the black hole can suck material out of the companion star. When the gases will swirl around and enter the black hole they will form a swirling disk, and the temperature of the gas will rise to the point where the matter will glow with high energies in the X-ray field.
The mass of the black hole created by the nuclear collapse of a star is doubtful if it exceeds a few times the mass of the sun, but any material that approaches the black hole will fall in and will not be able to escape. The extra material will widen the hole and increase the gravity of the hole. Black holes are hungry and insatiable. with can swallow entire stars or even other black holes.
Materials located near star clusters or galaxies can form supermassive black holes immediately, without that body going through a stellar phase. Many galaxies suffer from severe disintegration at their center. In some of them, huge jets of gas are sent out at speeds approaching the speed of light, others emit compressed radio waves or X-rays. Sometimes the center of the galaxy shines in a wide range of the spectrum. Spinning monstrous black holes, astronomers believe, could be responsible for these phenomena. These super holes draw material into them, releasing huge amounts of energy. This anergy is a challenge to the rotational movement of the black hole and thus thin plumes are formed that are thrown into space. There is evidence that some galaxies may contain black holes with the mass of a billion suns.
One type of object that emits enormous amounts of energy are quasars. Many astronomers are convinced that black holes are actually responsible for the colossal energy emitted by quasars. It is possible that most galaxies contain a massive black hole at their center, and that quasars are simply galaxies where the black hole has been eaten up with a lot of matter.
Other speculations were about the presence of a black hole at the center of our galaxy. For many years, astronomers have known about the presence of a strange, powerful and compact radio source called Sagittarius A. It appears as a giant black hole pumping gas into it. If this is indeed the case, the gas should also glow in the infrared range. This radiation was recently discovered. But the situation is embarrassing, so much so that some suspect that we may have not one but two black holes in the core of the galaxy.
One bone is devoured by the black hole and can't get out. Instead, the black hole grows and its appetite knows no bounds. Over time, the black hole regularly sucks in all the material and continues to expand. Many stars will face their fate, others will be shot into intergalactic space. Over the years it is likely that most objects in the universe will end up inside black holes. These black holes will spiral towards each other and create a monstrous black hole in an orgy of cannibalism.
It is possible that eventually the entire universe will collapse under its weight. All the stars that remain, all the stars that go away and all the black holes will merge into one cosmic contraction known as the Great Ingestion. If this scenario is true, then the entire universe will find its end inside a single giant black hole.
The article was translated at the time, but was not uploaded to the knowledge website. Saved in a printed version after all the files of that time, in the Einstein format, disappeared in the many transitions between computer generations.
