Scientists have announced the “perfect explosion” of two neutron stars: a stunning effect

Scientists managed to witness the “perfect explosion”. The merger of neutron stars creates a spherical cosmic explosion. The explosion, called a kilonova, created a rapidly expanding fireball of luminous matter before collapsing to form a black hole.

Astronomers have observed what could be a “perfect explosion,” a colossal and perfectly spherical explosion caused by the merger of two very dense remnants of stars called neutron stars, shortly before the combined formation collapsed to form a black hole.

Researchers on Wednesday described for the first time the contours of a type of explosion called a kilonova that occurs when neutron stars merge, Reuters reported. The rapidly expanding fireball of luminous matter they described in detail exceeded their expectations.

Two neutron stars, with a combined mass of about 2.7 times that of our Sun, orbited each other for billions of years before colliding at high speeds and exploding. This happened in a galaxy called NGC 4993, located about 140-150 million light-years from Earth in the direction of the constellation Hydra. A light year is the distance that light travels in a year – 9.5 trillion km.

The existence of kilonova explosions was proposed in 1974 and confirmed in 2013, but what they looked like was not known until this explosion was discovered in 2017 and studied extensively.

“This is the perfect explosion in several ways. It’s beautiful, both aesthetically, in its simplicity of form, and in its physical meaning,” says astrophysicist Albert Sneppen of the Cosmic Dawn Center in Copenhagen, lead author of the study, published in the journal Nature.

“Aesthetically, the colors emitted by the kilonova are literally similar to the sun – except, of course, that the surface area is several hundred million times larger. Physically, this spherical explosion contains the extraordinary physics behind this merger,” Sneppen added.

The researchers expected that the explosion might look like a flattened disk – a colossal luminous cosmic pancake, possibly with a jet of material flowing from it.

“Honestly, we’re really going back to the drawing board with this,” says Cosmic Dawn Center astrophysicist and study co-author Darah Watson.

“Given the extreme nature of physical conditions – much more extreme than, for example, a nuclear explosion, with densities greater than the atomic nucleus, temperatures in the billions of degrees, and magnetic fields strong enough to distort the shapes of atoms – there may well be fundamental physics here that we we don’t understand yet,” adds Watson.

According to Reuters, the kilonova was studied using the telescope of the European Southern Observatory, located in Chile.

Two neutron stars began their lives as massive ordinary stars in a two-star system called a binary. Each of them exploded and collapsed after running out of fuel, leaving behind a small and dense core about 20 km in diameter, but with more mass than the sun.

Very gradually they approached each other, rotating in orbit at high speed. Each of them was stretched and torn apart in the last seconds before the merger due to the strength of the gravitational field of the other. Their inner parts collided at about 25% the speed of light, creating the most intense magnetic fields in the universe. The explosion released the luminosity of about a billion suns for several days.

The two stars briefly formed a single, massive neutron star, which then collapsed to form a black hole, an even denser object with gravity so strong that not even light can escape.

The outer parts of the neutron stars, meanwhile, have been stretched out into long ribbons and some of the material has been ejected into space, Reuters says.

The researchers proposed several hypotheses to explain the spherical shape of the explosion, including the energy released by the huge magnetic field of a short-lived single neutron star, or the role of mysterious particles called neutrinos.

“This is truly amazing and an exciting challenge for any theorist and numerical modeler,” Sneppen says. – The game has begun”.