Watching the stars during a clear night sky fascinates you,right? Ever imagined what happens to them when they die? Stars exist for a very long time, but just like us,they do not live forever. They also gradually exhaust the fuel that keeps them alive.
A star glows throughout its active life as a result of thermonuclear fusion of hydrogen into helium in its core, producing energy that travels through the star’s interior and eventually radiates into outer space. If the star is an enormous one, it will explode when it reaches towards its end.
The star collapses on itself as a result of the explosion, making it considerably smaller. The star’s gravity becomes so strong that it swallows everything in its path, even light. And that is how a black hole is created. The reverse happens with a white hole. Many of the wonders of space are still unknown to us, but read on to find out what we do know about black holes and white holes.
What is a Black Hole and How is it Formed?
A black hole is one of the strangest,mysterious and powerful phenomena of the universe. In the 18th century, two physicists, John Michell and Pierre-Simon Laplace, suggested the concept of a black hole. With his general theory of relativity, Albert Einstein predicted the existence of black holes for the first time in 1916. The term “black hole” was coined in 1967 by physicist John Archibald Wheeler. Black holes can be found in the center of most galaxies.
Most black holes,regardless of size,form when a massive star runs out of energy, that is, at the end of its life cycle.The star collapses under its own weight and it results in an explosion which is called Supernova. The big star is eventually squashed into a tiny dot that you can’t see. As they continue to absorb light and mass around them,black holes can become enormously large.They have the potential to absorb other stars around them as well. Many scientists believe that supermassive black holes exist at the center of galaxies. The center of a black hole has a point that contains all of its mass.The point is called a singularity.
A black hole’s gravity, or attractive force, is so powerful given its small size and huge mass that it pulls in everything that gets too close to it. Nothing can move fast enough to escape the gravity of a black hole. There is a unique boundary that exists around a black hole,which is called the event horizon. At this point, everything must go towards the black hole. Once you’ve crossed the event horizon, there’s no escape for anything! This includes light, the fastest entity in the universe. That’s why we can’t see black holes in space — they’ve consumed all of the light.
Different Types of Black Holes
Supermassive Black Hole- It is among the biggest kind of black holes. They are up to a million times the size of our sun. This is the type of black hole that exists at the core of our galaxy,the Milky Way. It is known as Sagittarius A* (A* is scientific code for “A-star.”)
Stellar Black Holes- They are the most frequent form of black hole, are only up to 20 times more massive than our sun. Stellar black holes are most commonly discovered in X-ray binary systems,when gas from a companion star is being pulled towards the black hole. Currently there are about 20 X-ray binary systems that are believed to have stellar black holes.
Intermediate Black Holes- Recent research has indicated that midsize, or intermediate, black holes (IMBHs), may occur. They might develop as a result of a chain reaction between stars in a cluster. Several of these IMBHs that originate in the same region might potentially collide in the center of a galaxy to generate a supermassive black hole.
More About Black Holes
Though astronomers cannot see black holes, they know that black holes exist by the effect they have on objects that approach too close to them.
Strange things happen around black holes which have connections with quantum physics and space time.
Despite the fact that they are extremely real, they are a favourite subject for science fiction stories.
Although thousands of possible black holes have been identified, NASA believes there might be billions more in space.
Black holes do not exist forever. They gradually evaporate, returning their energy to the cosmos.
The mass and spin of black holes varies from one another. Apart from that, they’re all fairly similar.
What is a White Hole?
A white hole is a recently found phenomenon in the realm of astronomy. It is a strange cosmic phenomenon which is intensely bright and from which matter gushes rather than disappearing. Dmitriyevich Novikov first proposed the existence of white holes in 1964, and it can be described as a fictitious celestial body that emits energy. They have characteristics such as charge, mass, momentum,etc.
Existence of white holes is predicted by Einstein’s theory of relativity and is most frequently mentioned in the context of wormholes, where a black hole acts as the entrance point to a tunnel across space and time that ends in a white hole somewhere else in the Universe.
According to the rule of general relativity, if there are black holes in the cosmos, there must also be white holes. A white hole is the counterpart of a black hole in astrophysics or it can be regarded as a time reversal of a black hole. While a black hole absorbs everything that passes its event horizon, on the other hand, a white hole expels everything that was lost in the black hole.It pushes out any nearby matter. Though the existence of white hole is not completely authentic,It is believed that even if a white hole does form, it will be extremely unstable and would most likely last a few seconds.
The Big Bang explosion has been categorised as a white hole. In 2006, there was a 102-second gamma-ray burst known as 060614. Normally, gamma ray bursts have a limited lifetime, so it was unexpected to observe one that lasted over two minutes. Everyone assumed it was caused by a supernova, but there were no supernovae which matched with that particular burst. Some scientists think it was a white hole. The force and length of this gamma-ray burst are comparable with the existence of a white hole. Because it is a new theory, not all astronomers have accepted it, though it might be a possibility.
Some theorists,however, believe that integrating Einstein’s theory and quantum theory hints to a new way of thinking about white holes. Instead of being the ‘exit’ from a wormhole, they may be a slow-motion replay of the formation of black hole.
The process is initiated when a big old star collapses under its own weight and forms a black hole. However, quantum effects occurring on the black hole’s surface prevents further collapse to a singularity and instead begin to gradually transform the black hole into a white hole that pushes out the original star matter again. However, the process is mind-bogglingly slow, so we may have to wait for a very long time to find out if white holes really exist.
Scientists believe that connecting a white hole and a black hole can create a wormhole. John Wheeler, a theoretical physicist, coined the phrase “wormhole.” It is sometimes referred to as an Einstein-Rosen bridge. A wormhole is a theoretical tunnel with two ends, each with different points in space time, that creates a shortcut via time and space.Alternatively, it is hypothesized that if you connected a white hole from the past to a black hole today, you might build a time machine. The possibilities are limitless.
Someday,humans may be able to use black holes to travel forward in time. An astronaut could take a short visit near a black hole and return to Earth after years, decades, or even centuries had passed there. A black hole time machine may be used to discover what the Earth would be like in the future.What about going back in time? That is a completely distinct challenge!