Astronomers are captivated by a 'perfect explosion,' a spherical cosmic fireball

A neutron star collision unleashed the light of a billion suns for days.

Key Takeaways

Astronomers observed a rare, nearly perfect spherical explosion from a neutron star merger.
The kilonova glowed as brightly as a billion suns for a few days.
The explosion forged gold, platinum, uranium, and other heavy elements in extreme conditions.
The spherical shape surprised scientists, defying prior models of kilonova explosions.
Researchers are revisiting physics theories to understand this remarkable event.

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The Perfect Cosmic Fireball

Astronomers have unveiled the extraordinary details of a nearly perfect spherical explosion—a kilonova—caused by the collision of two neutron stars. This dramatic event unfolded in 2017 in the galaxy NGC 4993, located 140–150 million light years from Earth in the Hydra constellation. With a combined mass of 2.7 times that of the sun, the neutron stars had orbited each other for billions of years before their explosive merger.

Lead researcher Albert Sneppen of the Cosmic Dawn Center described the event as “a perfect explosion” due to its symmetry and scientific implications. The kilonova’s luminous fireball emitted a light equivalent to a billion suns for several days, dwarfing any earthly nuclear explosion in intensity.

A handout illustration of perfectly spherical explosion, called a kilonova — A perfectly spherical explosion, called a kilonova, that followed the merger of two very defense objects called neutron stars – remnants of massive stars after supernova explosions ? that was observed 140-150 million light-years away from Earth is seen in this handout illustration obtained by Reuters

A Breakthrough in Understanding Kilonovae

Using the European Southern Observatory’s Very Large Telescope in Chile, scientists were astonished by the spherical nature of the explosion. Previous models predicted a flattened disk-like shape with potential jets of material. This finding challenges established theories and suggests there may be unknown physics at play, as co-author Darach Watson noted.

The merger also generated the universe’s most extreme magnetic fields, stretching the neutron stars into streamers before flinging their material into space. The intense temperatures and densities created during this process led to the formation of heavy elements such as gold, platinum, and uranium, essential for understanding cosmic evolution.

Researchers hypothesize that the spherical shape might result from the short-lived massive neutron star’s magnetic field or the influence of neutrinos, enigmatic subatomic particles. The findings, published in Nature, signal the need to revise existing models and could unlock new frontiers in astrophysics.