Scientists have delved into the possible aftermath of a neutron star collision, or kilonova, near Earth. These events, while being among the most powerful in the universe, are also exceedingly rare. However, if one were to occur in close proximity to our planet, the consequences could be dire.
Haille Perkins, a scientist at the University of Illinois Urbana-Champaign, stated that a neutron star merger within about 36 light-years of Earth could lead to an extinction-level event. These kilonovas are so intense because neutron stars, the remnants of dead stars, are incredibly dense. A teaspoon of neutron star material would weigh approximately 10 million tons on Earth.
Kilonovas produce gamma rays, cosmic rays, and even gravitational waves that can be detected billions of light years away. These gamma rays, in particular, can strip electrons from atoms, leading to ionization. If Earth were directly in the path of these rays, they could destroy our ozone layer, exposing the planet to harmful ultraviolet radiation from the sun.
While the gamma-ray effects are short-lived, the X-ray afterglow resulting from the gamma rays interacting with the interstellar medium could also damage the ozone layer. The most concerning aspect, however, is the cosmic rays produced by the kilonova. These could strip the ozone layer and expose Earth to harmful ultraviolet rays for thousands of years.
Despite the potential dangers, such an event is highly unlikely to affect Earth. Perkins emphasized that neutron star mergers are extremely rare. In the Milky Way’s 100 billion stars, only one potential kilonova progenitor system has been identified so far.
Other cosmic events, such as solar flares, asteroid impacts, and supernova explosions, pose a more significant threat to Earth. For instance, an asteroid impact led to the extinction of non-avian dinosaurs around 66 million years ago.
The research on kilonovas, while highlighting potential dangers, also aids in the search for life elsewhere in the universe. It provides insights into systems that might not support life as we know it.
The team’s findings are available on the open-access paper repository arXiv.