What is a ‘Black Hole’?
Black Holes are formed when a massive star collapses or dies. With their immense gravity they pull everything that gets too close into their depths; this pull is so powerful that nothing can escape the brutal wrench of a black hole, not even light. The spherical boundary of a black hole is known as event horizon. If any object passes close to an event horizon then it’s certainly going to be absorbed completely and won’t reemerge. Black hole’s spinning rates are quite fast and they are extremely long lived. There are different categories of black holes, wherein each depends on the amount of mass and density. They can be as small as an atom or as massive as the mass of 1 million suns.
A detailed explanation of a Black Hole:
Normally an atom consists of a core of protons, neutrons (The nucleus) orbited by electrons. Relatively speaking, there is a lot of room between the nucleus and the electrons. Compare it to a football field: put an orange (the nucleus) on the center spot and some peas (electrons) on the outside lines. The biggest part of the field is now empty, in a black hole atoms have collapsed under their own gravitational pull and there is no more room between the nuclei and electrons which leads to a very high concentration of mass on a very small area and this generates the extreme gravitational effects of a black hole. Consequently mass in a black hole has an extremely low volume for e.g. A black hole with the weight of a car would be the size of about 10-24m.
Below are the most-asked questions about the peculiarities of black holes. Uncover more mysteries as you read about this extra-ordinary phenomenon.
- When were they born?
Black holes are always forming and evaporating throughout the universe and throughout the ages and they have been here since the big bang. (It was the explosion of dense matter, which according to current cosmological theories marked the beginning of the universe.)
- What do black holes do in space?
They have an irresistible gravitational pull which attracts various stars and other objects inside them. They thrive on the absorption of matter that they pull. They are ultimate energy factories and thus spend most of their time converting mass into energy.
- What do black holes do in space?
They have an irresistible gravitational pull which attracts not only matter, like meteors, planets and even stars but also light. They thrive on the absorption of matter that they pull. They are ultimate energy factories and thus spend most of their time converting mass into energy.
- How does a star end up as a black hole?
Whenever a star runs out of energy and is not able to replace its lost energy through nuclear fusion, then gravity takes over its internal pressure. Ultimately the star starts contracting slowly and collapsing rapidly. This star will then inevitably end up as a black hole.
- Do black holes make noise?
Sound made by a black hole which can travel through space has a wavelength of several light years. These high wavelengths can travel through space; however there is no species on earth who are able to hear a sound this deep as sound doesn’t travel through empty space.
- Are black holes entirely black? Can a black hole be seen and how do they look like?
The black hole itself is entirely black since no light can escape it, so it cannot be seen! An (accretion disks)is mostly present around a black hole so it can be used as an indication that there is a black hole in the center.
- Do black holes emit radiation?
Since a black hole turns mass into radiation they emit a lot of radiation, however the more radiation it emits, the smaller it gets.
- What will happen if we enter a black hole?
We would quickly fall towards the center where we would be killed by the enormous tidal forces of the Black Hole. The gravitational pull of the black hole will be so high you will almost reach light speed when nearing the hole. Since the laws of physics prevent you from reaching light speed, all sorts of crazy things start to happen then, like time slow down and your mass increases. Also there are theories about people being stretched because of the difference in gravitational pull between the body parts closest and furthest from the event horizon.
- Nothing can travel at the speed of light, then how can a black hole pull the light into itself?
When the gravitational pull on the light particle is larger than or equal to the total energy of the particle, it will be absorbed.
- How big can a black hole get?
There is no limit to how large a black hole can get. The largest of galaxies can be equivalent to a billion suns.
- What usually happens when two black holes collide?
If two black holes collide, they merge to become one enormous black hole. They cannot escape gravity of each other. This event always turns out to be extremely violent.
- How many categories of black holes are there?
Black Holes have two broad categories-
- Stellar Mass- It is produced when a star explodes. Their mass can range up to twenty times to that of the sun.
- Supermassive Black Holes- Most galaxies, including Earth’s galaxy- Milky Way contains supermassive black holes. It is million and billion times the mass of the Sun and found at the core of galaxies. Just about every large galaxy has a supermassive black hole at its core. Astrophysicists have calculated the velocity of a supermassive black hole that has been spinning at the center of spiral galaxy and located in NGC 1365 that is a bunch of planets and stars 56 million light years away in the formax constellation. Due to its spinning it gas dragged all those stars into it like water that swirls into a shower drain.
- Would a black hole leak and disperse in future?
Yes, there is a possibility that particles of matter start leaking out of the black hole, usually after a long time after the object falls into it. After this dispersion of matter, it spreads all throughout the universe.
- Do black holes pose threat to Earth?
The matter that is pulled into a black hole gets so hot it furiously emit X-rays and highly energetic forms of light that if anything falls in it will probably get fried.
As far as the Earth is concerned, black holes don’t pose an immediate threat. The nearest black hole is 1600 light years away and is much too far to exert any gravitational pull. It is not anywhere close to Earth to bother our scientists.
But, having said all that, a black hole could be dangerous in one way. Scientists have been suspecting that black holes may be the leading creator of ‘gamma ray bursts’ (massive explosions) that can destroy even supernovas. If ever such event takes place in our galaxy, there is a slight possibility it would cause extinction by messing with the ozone. A mass extinction that took place millions of years ago could have been caused by such a blast. Fortunately such bursts take place once per 100000 or 1000000 years in our galaxy, and there are few chances that these burst would be aligned to Earth.