Black holes are probably the biggest mystery in the known universe!
Until now we know very little about them, because our technology does not yet allow us to study their characteristics in depth, mainly because they are all very far from our solar system.
Another reason why it is so difficult to study the black holes in the universe, is that these do not emit light pulses like stars do, on the contrary, their powerful gravitational field is capable of absorbing even nearby light, but this is something that we will explain later.
However, from 1970 and thanks to the theories proposed by Stephen hawkings about black holes, we have been able to understand much more about them, including demonstrable data about their shape, composition, formation process and even their relationship in the alterations of temporal continuity.
Comets can be just as interesting as black holes! Don't miss our full article on the parts of a comet
But what do we really know about black holes?
If you ever saw the Christopher Nolan movie: Interstellar (2010) and you were left without understanding anything at all, then it's because you still don't know enough about the black holes.
I tell you, the film is based on Einstein's general relativity theory, which states that our universe does not have 3 dimensions, but 4, with time being the fourth dimension in the plane of reality.
Therefore, the rules of universal mechanics affect time, just as they do matter, including light.
In this way, time would not be a universal constant, but a dimension that can be deformed, stretched or contracted like an elastic band, according to the laws of physics, like the gravity.
Interested in learning more about black holes in space?
Then do not stop reading this article until the end, because we explain everything you need to know about this interesting topic, so that the next time you see Interstellar, you do not feel literally lost in space.
What are black holes?
Black holes aren't really holes, did you know that?
In fact, according to the theorem of Hawkins and Ellis Since 1970, black holes are believed to be spheroid in shape due to the attraction of their own mass towards their center, due to the action of their own gravity. The same thing that happens with stars, but on a scale millions of times higher.
Black holes are a point in space, made up of a cluster of extremely dense mass, which generates a gravitational force so powerful that it is capable of creating a curvature in the continuity of space-time.
The gravitational field of black holes is so strong, that no particle of matter is able to escape the deformation if it gets too close. In fact, the attraction is so powerful that it is capable of absorbing the photon particles that form the rays of sunlight.
That's right, they're called black holes because they're capable of literally swallowing the light around them.
How dense are black holes?
The physical characteristic that gives the supermassive black holes their gravitational and thermal properties, is the extreme density of matter they contain in a relatively small area of space.
For the amount of matter that makes up our own star to become a black hole, it would have to fold in on itself in an extreme way, compressing all its particles from a size of 1.300 million kilometers. to a space no larger than 2 kilometers in diameter.
Therefore, the sun would have to reduce its size almost 900.000 times, but without wasting any of the matter that makes it up.
Space-Time Curvature
Have you ever wondered how a black hole is capable of slowing down time?
Did you remember Gargantua en Interstellar?
In the movie, the spaceship Endurance is forced to make a stop to collect data on the perspective of life in the miller planet, which coincidentally orbits very close to a supermassive black hole called Gargantua.
Due to this, the crew faces an astrophysical dilemma: Due to its proximity to Gargantua, time passes much slower on the planet than on Earth, so the search mission, which for them would take a couple of hours, on Earth it would mean several years.
But how is this possible?
If it seems like a strange concept to you, it is because we are used to considering time as an invariable constant of the universe, basically because we do not have any tool that can deform it, as we do with the other planes of reality.
However, the theory of General Relativity, proposed by Albert Einstein in 1915, suggests that time is a dimension of reality that extends over the X and Y planes (the dimensions of width and length).
Therefore, if a body with mass exerts an action on the plane of reality, it will create a variable of dimension Z (depth) that can deform the first two and, therefore, can also do so over time.
Let's look at it this way:
Imagine that you extend a piece of cloth, creating a flat space (dimensions X and Y); and on the cloth you drop a ball. The action of the weight of the ball on the fabric will create a concave underside of the plane.
This effect is what in astrophysics is known as Curvature of space-time.
Now, due to the rules of physics, the heavier the object that is placed on the plane, the more marked its action on it, and therefore the deeper the curvature would be.
This is exactly what happens with the black holes and curved time.
When compressed to the limit, black holes become incredibly dense objects -and therefore heavy-, so the action they exert on the X and Y planes is really extreme.
The curvature caused by black holes is so strong that it does not allow the matter that enters to escape, this causes a space-time singularity that we know as Event Horizon.
The curvature that black holes create is so "deep" and their gravitational attraction so powerful that they suck in everything that comes near them, therefore, being in the warping vortex of space produced by Gargantua, the planet Miller he was experiencing a warp in his time continuum, slowing it down by having to enter Gargantua's Event Horizon.
In fact, the exact figure is that every hour spent in Miller It was equivalent to 7 Earth years.
As a curious fact, the 1 km high waves that cover the entire surface of Miller, They would also be explained as an effect of the gravitational power exerted by the black hole on the planet.
How do black holes form?
It could be said that black holes are the residue left behind by stars after they die.
Until a couple of decades ago, it was believed that black holes formed during the early stages of the universe and that this phenomenon would not have repeated itself.
However, the study History of Time: from the Big Bang to black holes, created in collaboration by Hawkings, Oppenheimer, and Roger Penrose, showed that black holes are created in a process called gravitational collapse.
To understand the gravitational collapse that gives way to the formation of black holes, we have to go back a bit, to the process of death of stars.
when to one Yellow star (like our sun) depletes its hydrogen reserves, it begins to burn the helium particles on its surface, in a much more intense nuclear fusion process. As this process continues, the star, which is approaching its last stage of life, can increase up to 300 times its size and change its color, becoming a Red Giant Star.
By consuming all the fuel on its surface, the nuclear fusion processes will stop, and without any process to counteract the force of its own gravity, all its particles will begin to be drawn towards its own core, reducing its size once again and creating what we know as a White Dwarf Stara dead star
However, the large amount of mass of a star can cause this process to be taken to an extreme, compressing the White Dwarf beyond its own limits and creating a body with even more concentrated mass in an incredibly small space.
It's like trying to bend our sun enough to put it in the trunk of your vehicle.
This last step makes the resulting gravitational field so powerful that it begins to swallow its own light, which ends up turn a star into a black hole.
types of black holes
There are different types of black holes and these are classified according to their size and the amount of mass they contain.
supermassive black hole
Supermassive black holes are arguably the largest and most powerful. These can contain several million times the mass of our sun in a space only 2 or 3 times larger, which also makes them very powerful.
It is common to find supermassive black holes dominating the centers of many large galaxies, especially elliptical galaxies. A clear example can be found at home, since the Milky Way revolves around Sagittarius A, a really huge supermassive black hole measuring about 120 AU.
Intermediate-mass black holes
They are next on the scale according to their mass. They're less dense than supermassive black holes, but they're still really impressive.
Black holes with an equivalent mass of between 100 and 1.000.000 solar masses fall within this classification.
stellar mass black holes
They are quite common and from planet Earth we have been able to observe several black holes that fit into this classification.
Stellar-mass black holes contain between 30 and 70 solar masses in their interior. These form from the gravitational collapse of massive stars, known in astrophysics as Supernovae.
micro black holes
Micro black holes are a category of this classification, however, they remain a hypothesis.
According to Hawkins theory About black holes, these micro black holes would contain surprising amounts of matter in an extremely small space, so the matter inside them could be governed by the rules of quantum physics.
One of the missions of the large hadron collider at CERN is to create the elements to form an artificial micro black hole, where several theories about quantum physics could be tested or, in the end, a particle could be isolated from dark matter.