New discovery! The largest known explosion in the universe has not stopped for 3 years

Xinhua News Agency, Beijing, May 12th. Astronomers announced on the 12th that they had observed the "largest" explosion in the universe so far. The fireball produced was equivalent to the size of 100 solar systems, and the explosion lasted for at least 3 years and has not stopped.

According to AFP, the explosion was named AT2021lwx and was located deep in the universe 8 billion light-years away from Earth. It occurred when the universe was 6 billion years old. The research report was published in the Monthly Notices of the Royal Astronomical Society. A study published in 2021 showed that the universe is 13.77 billion years old, with an error of about 40 million years.

This is the first photo of the supermassive black hole at the center of the Milky Way, released simultaneously by astronomers from many parts of the world, including China, on May 12, 2022. Xinhua News Agency (Photo courtesy of the Event Horizon Telescope)

Researchers estimate that the brightness of AT2021lwx's explosion is 2 trillion times brighter than the sun, which is not the brightest explosion observed so far. However, the main author of the research report, Philip Wiseman, an astrophysicist at the University of Southampton in the UK, said that the energy released by AT2021lwx's explosion in three years exceeds the brightest gamma-ray burst GRB 221009A observed so far, making it the largest explosion observed in the universe so far.

The gamma-ray burst GRB 221009A was observed in October last year and ended 10 hours after it was discovered.

Researchers first discovered AT2021lwx in 2020 using the Zwicky Transient Research Facility in California, but it was not until they later observed it with a more powerful astronomical telescope that they realized the scale and power of the explosion. There is no definitive answer as to what caused the explosion.

A schematic diagram shows a white dwarf devouring matter from its giant companion in a binary star system. Xinhua News Agency (provided by Australian National University)

The researchers speculate that the most likely scenario is that a supermassive black hole slowly devoured a huge gas cloud 5,000 times larger than the sun, causing the AT2021lwx explosion. However, Wiseman said that this explanation is not absolute, and the researchers are working to test it using new models.

They also considered other possibilities, including a supernova explosion or a tidal disruption event, which is the process of releasing energy when a star is torn apart by a supermassive black hole. However, AT2021lwx is 10 times brighter than previously observed supernova explosions and 3 times brighter than tidal disruption events.

The only cosmic event with a brightness comparable to that of AT2021lwx is a quasar, a supermassive black hole that emits strong light as it devours a vast amount of gas at the center of a galaxy. However, Wiseman said that the light emitted by quasars usually flickers, and AT2021lwx suddenly appeared three years ago and is still shining today, which is unprecedented. (Yuan Yuan)