What is a supernova? Details revealed as astronomers witness the largest cosmic explosion 10 times brighter than any explosion of a star

Astronomers have recently witnessed the largest-ever cosmic explosion and named the event AT2021lwx. It is said to have been 10 times brighter than any known supernova. For those unfamiliar with the term, Space.com defines a supernova as an event that takes place when a star, having reached the end of its lifetime, explodes in a "brilliant burst of light." Thus, it is referred to as the explosion of a star.

As per Encyclopedia Britannica, supernova can be termed as any exploding stars, provided their brightness after eruption suddenly upsurges millions of times its average level. As stated by Space.com, supernova can even outshine entire galaxies for a brief period. At the same time, they radiate far more energy than Earth's sun can in its lifetime.

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The luminosity of AT2021lwx, the newly witnessed largest cosmic explosion, is said to last over three years

The brightness of the newly-discovered largest cosmic explosion, AT2021lwx, is also said to last for more than three years. The observed period is much more extended than most of the supernova. Most supernova are usually observed to remain luminous only for a few months.

Interestingly, AT2021lwx is also observed to be three times brighter than TDEs (tidal disruption events). TDE is a phenomenon of the destruction of a star by a supermassive black hole when the former approaches sufficiently close to the latter, only to be pulled apart.

Reportedly, the cosmic explosion started as an unremarkable flash in the sky and was first detected in November 2020 by California's Zwicky Transient Facility. After a few months of the first detection, ATLAS (Asteroid Terrestrial-impact Last Alert System) in Hawaii tried to observe the event again.

However, none of the observations indicated how far AT2021lwx had occurred. Last year, the team of astronomers led by Dr. Philip Wiseman from the University of Southampton was able to analyze the light from the cosmic explosion and trace the distance to eight billion light years away.

Dr. Wiseman, a research fellow at the University of Southampton, was leading a team searching for a type of supernova when their search algorithm flagged AT2021lwx by chance. Observing the unusual behavior of the phenomenon of being brighter for over two years in comparison to most supernova and TDEs, Dr. Wiseman noted:

"Most supernovae and tidal disruption events only last for a couple of months before fading away. For something to be bright for two plus years was immediately very unusual."

The researchers have theorized that the largest ever cosmic explosion could result from an enormous cloud of gas being swallowed by a supermassive black hole. Additionally, the observers reportedly estimate that the size of the gigantic cloud of gas could be thousands of times larger sun in Earth's solar system.

Besides the cloud of gas, the AT2021lwx has been estimated as a fireball that can be 100 times the size of Earth's solar system, while brightness can be around two trillion times that of the sun. Moreover, during its three years of brightness, AT2021lwx can radiate an estimated 100 times the energy that the sun will in its lifetime (10 billion years).