Neutron star collision can annihilate Earth’s ozone layer, leaving it devoid of life for thousands of years

Small as they are per cosmic standards, neutron stars make up for their size with their density. Just a teaspoon of these remnants of colossal supergiant stars would weigh a staggering 10 million tons here on Earth!

But what happens when two such neutron stars bump into each other and decide to romance each other? Well they set off a dazzling display of light, known as a kilonova, marking one of the most violent events in the known universe. Talk about explosive chemistry!

However, detecting such an encounter is akin to finding a needle in a cosmic haystack. Only one kilonova resulting from the collision of neutron stars has been documented to date: in 2017, gravitational wave signal GW 170817 was detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO), along with its accompanying gamma-ray burst GRB 170817A. This exceptional event occurred at a distance of 130 million light-years away.

Remarkably, we can detect these waves on Earth, even after they've traversed billions of light-years. But very recently, a team of scientists decided to explore the hypothetical possibility of such a kilonova occurring much closer to our planet, say a mere 36 light years away. And it would be an understatement to say that the aftermath would be catastrophic for Earth.

These celestial encounters unleash a torrent of destructive forces, including gamma rays and cosmic rays – high-energy charged particles moving at near-light speeds – in mind-boggling quantities.

The most immediate peril from a neutron star merger comes from the gamma rays they unleash. These high-energy rays can strip electrons from atoms, a process known as ionisation, and in the process, obliterate Earth's protective ozone layer. However, for this grim scenario to unfold, our planet must find itself directly in the crosshairs of the gamma-ray jets. Fortunately, this is a relatively localised effect.

However, the true disaster would arise from highly energetic charged particles, aptly named cosmic rays. Should these particles find their way to Earth, they would mercilessly strip away our ozone layer, rendering our planet vulnerable to ultraviolet radiation for thousands of years! In essence, this could transform Earth into an inhospitable wasteland.

Before you start stockpiling canned food and constructing underground bunkers, it's essential to grasp the rarity of such an event. Neutron star mergers are not only uncommon but also have a limited range of lethality. In the grand scheme of things, we have more immediate cosmic perils to contemplate, such as solar flares, asteroid impacts, and supernova explosions. While neutron star mergers make for a captivating thought experiment, these other cosmic threats demand our immediate attention.