Mohammed Misbah Tamanna, X, The Blossoms School, Aligarh

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Black holes are perhaps one of the most mysterious objects in our whole universe.
We all know that a black hole is defined as a region of space-time where the gravity is so strong, even light can't escape from it.
Well, instead of just delving into the details of black holes, let us first clear our minds of some common misconceptions associated with black holes-

Black holes are ‘holes’ in space
Black holes are spherical, have mass, occupy space, and spin pretty much like any other astronomical object.

Nothing can come out of a black hole
The point is, only some of the matter pulled by its gravity manages to make it all the way into the black hole. The rest of the matter escapes along the black hole's axis, exiting the area, and often galaxies altogether. These outflows span tens or hundreds of thousands of light years across. Besides this, all black holes give out a very faint glimmer of radiation, known as Hawking radiation. In order to understand Hawking radiation, we must first look closely at what we think of empty space. In reality, empty space isn't really empty. It is filled with virtual particles popping into existence all the time and annihilating each other. When these virtual particles pop up right at the edge of a black hole, then one of the virtual particles gets drawn into the black hole and the other escapes and become a real particle. So the black hole loses mass as energy comes out of it. One such outflow can be observed at our own galaxy - The Milky Way's Fermi Bubbles, which are named after NASA's Fermi Gamma-Ray Telescope.

Black holes are black
Contrary to the name, a black hole isn't black. Imagine that you are outside a black hole and you see someone moving towards the black hole as they pass the event horizon. You will see that the light emitted from them would get fainter, redder (its wavelength will increase) and their position would asymptote towards the event horizon. The photons (particles of light) that they emit would appear to get stretched out in space and in time. As you keep observing, you will see the light transition from infrared to microwave to radio frequencies and yet never quite disappear. Even infinitely into the future there will be light to observe from their fall into the black hole. With a large enough telescope that is sensitive to long wavelengths, you can theoretically observe light emitted from anything that falls into a black hole. As someone or something falls in, their light never completely goes away, just gets fainter, so as to speak. Another point is that the object's light can still be emitted before it reaches the event horizon. Black holes power some of the brightest objects in the universe known as quasars. As some objects get closer to black holes, they speed up as they near the event horizon and they shine brightly until they pass the event horizon.

We can see black holes
Black holes were first predicted in 1916, and it took us more than a century to get our first picture of the black hole. We also know that even light cannot escape from a black hole. But wait, if we cannot see black holes, then how do we find them and how did we take a photo of one? Well, there are two basic ways of detecting black holes- First, we detect black holes by observing how they influence or attract their surrounding matter by their gravitational pull. For example, at the centre of Milky Way, we see an empty spot where all the stars are circling around as if they were orbiting a dense mass. This dense mass indicates the presence of a black hole. The second way is by observing the matter that falls into the black hole. The matter that falls in settles as a disk around the black hole and it gets hot and starts emitting radiation in the form of light. Telescopes can detect this radiation emitted by the swirling matter falling into them.

Black holes suck up everything that come near them
Okay this is an easy one. Before we continue, we need to understand what an event horizon is. The event horizon is a boundary. The curvature of space is so strong inside the event horizon that nothing, not even light, can escape once it has crossed the boundary. It's a popular opinion among some people that black holes are like vacuum cleaners and that anything near a black hole would get sucked up inside. This is, however, incorrect. Consider this, if we were to replace our own sun with an equally massive black hole, it won't disturb the orbit of the planets at all. The point is, that black holes have a limit i.e. the event horizon. It's true that anything that goes beyond a black hole would never return, but if a particle misses the event horizon and simply approaches near the black hole, it will experience just immense acceleration.

All stars will end up as black holes
Only stars with large masses become black holes. Our Sun at the end of its lifetime, it will die a quiet death and become a white dwarf star. Stars are sustained by the nuclear fusion reactions taking place in their cores. The heat energy that these reactions produce is enough to support their mass against their gravity. As a star runs out of fuel, it expands and starts to produce heavier elements like carbon and iron. Once it finally exhausts all its fuel, it collapses under it own gravity. It is at this stage when its mass decides its fate. A star needs to be at least 20 times the mass of our Sun to explode in a supernova explosion which leaves behind a black hole.

The LHC can create black holes which could swallow up the Earth
The Large Hadron Collider is the world's largest and powerful particle accelerator, built by the European Organization for Nuclear Research (CERN). With its 27-kilometre ring of superconducting magnets and with several accelerating structures, it lies as deep as 175 metres underneath the France-Switzerland border near Geneva. While skeptics have accused the LHC, that it could create various catastrophes for our Earth, the most common of them is that it could create a black hole. At its current stage, it's impossible for the LHC to make a black hole. However, for the sake of argument, let's say that it can create, and it does. So, could the black hole now consume the earth? Nope. Why? Because our hypothetical black hole would be microscopic. And this microscopic black hole would be extremely unstable and not survive because of Hawking radiation and would decay instantly. As one Forbes' article states: For a black hole of mass 5×10^-20 grams, the decay time in three dimensions would be 10^-83 seconds, which is not even enough time to exist! For physics to be meaningful, we need a time of about 10^-43 seconds or longer. Translated into black hole mass, we'd need it to be at least 0.00002 grams to have even a chance of existing. I think we can safely say for now that the LHC cannot create a black hole which ends up consuming the earth and destroying humanity.

Black holes can be portals to other places
A simple answer to this question, as Professor Richard Massey puts it, is Who knows? He further explains, Falling through an event horizon is literally passing beyond the veil - once someone falls past it, nobody could ever send a message back. They'd be ripped to pieces by the enormous gravity, so I doubt anyone falling through would get anywhere. The idea that black holes could lead somewhere has arisen because of the wormhole theory or as Einstein called it- white holes, in 1916. It was the hypothetical reversal of a black hole, into which, nothing could get in. Both Entrances (the black hole and the white hole) would be connected by a space-time conduit. It would be just like a bridge through space-time, theoretically creating a shortcut between two different points that could reduce travel time and distance. This idea was defeated because any object falling into the black hole would get torn apart by the black hole's gravity by the process known as spaghettification. It basically means, that the strong gravitational field of the black hole will pull you into a long, thin chain of atoms (like a spaghetti) if you venture close, and you will just add up to the black hole's mass.

Thus, no object can really survive a fall into the black hole because of the impenetrable barrier of singularity that ends up crushing whatever it encounters.
For now, the concept of black holes leading to places is just science fiction. We don't exactly know what happens what happens when the concept of a singularity comes into play.

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