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This newly found threat comes from a supernova’s blast wave striking dense gas surrounding the exploded star. (Photo: Nasa)
Kilonova Stampout
Even if they were dozens of light-years away, two colliding neutron stars could create a powerful enough explosion to finish life on Earth.
At least, that’s according to a recent paper published in The Astrophysical Journal, in which a team of scientists concluded that a kilonova could cause a major threat to Earth-like planets, even at formidable interstellar distances.
A kilonova is usually the result of a collision involving two neutron stars within a binary system, or when a neutron star and a black hole mix ups. These collisions release brain-melting amounts of electromagnetic radiation in the form of gamma-ray bursts.
The good news: to our current knowledge, there aren’t any neutron star pairs threatening to clash anywhere near Earth, as Universe Today reports, which means we’re safe from terrifying kilonovae. But it’s very bad news for any civilizations whose stellar neighbors might be a ticking time bomb and living in these dangerous circumstances.
Too Close for Consolation
The scientists based their research on a kilonova dubbed GW170817, which was spotted in 2017 by the LIGO and Virgo gravitational wave observatories, and believed to be triggered by a binary pair of neutron stars mixing some 130 million light-years from Earth.
Through computer simulations, the team tried to estimate the minimum distance at which such an event could still be safe.
They found that a kilonova about 16 light-years from Earth could produce enough of an X-ray afterglow to ionize our atmosphere. Even at distances of up to 36 light-years away, the kilonova’s terrible shockwave could interact with particles to make enough cosmic rays to vaporize our atmosphere, leaving us exposed to cryogenic temperatures, searing UV radiation, and a complete lack of oxygen.
Put simply, it’d likely be the end of life on Earth.
“The specific distance of safety and component that is most dangerous is uncertain as many of the impacts depend on properties like viewing angle to the event, the power of the blast, the mass of material ejected, and more,” lead author and University of Illinois Urbana-Champaign scientist Haille Perkins told last year of the then-not-yet-published research.
“With the combination of parameters we select, it seems that the cosmic rays will be the most threatening,” she added.
While that may sound like a terrifying prospect, as Universe Today points out, there are no binary neutron stars within just 36 light-years that are expected to merge — though, for approach, there are dozens of stars within that distance.
Nonetheless, there’s still many things to learn about the phenomenon.
“Currently, we only have one confirmed detection of a kilonova from a binary neutron star merger, so any more observations will constrain the unknowns,” Perkins told us.
