Scientists have discovered the possible consequences of neutron star collisions that occur near Earth, and found that these so-called kilonovas can be real killers that can destroy humanity. But don’t worry, the collision will have to be indeed close to wreaking havoc on our planet. Anyway, here’s what could go down.
“We found that if the merger of a neutron star can happen between 36 light-years of The worldthe resulting radiation could cause an extinction-level event,” Haille Perkins, team leader and scientist at the University of Illinois Urbana-Champaign, told Space.com.
A neutron star collision that creates a burst of light, called kilonovas, are considered the most violent and powerful events in the known universe. This is perhaps not surprising, given that neutron stars are the fallen remains of dead stars and are made of material so dense that a single teaspoon brought to Earth would weigh 10 million tons. That’s the equivalent of 350 liberties measured in a tablespoon.
These mergers of dead stars not only create bursts of gamma rays and showers of charged particles traveling at near the speed of light, known as cosmic rays, but they also produce the only deposits we know of that are turbulent enough to form elements heavier than lead, such as gold and platinum. These features cannot even be created at the incredibly high temperatures and pressures found in giant hearts. stars.
In addition, a neutron star integration set the fabric of space “screaming” waves called gravitational waves, can be detected here on Earth — even after traveling millions of light years away.
“Neutron stars can exist in binary systems, and when they merge, they produce a rare but spectacular event,” Perkins said.
Related: What happens when neutron stars collide? Astronomers may finally know
The team’s research was based on the observation of a neutron star merger behind the gravitational wave signal GW 170817, which was captured by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in 2017, and the gamma-ray burst GRB 170817A.
Occurring about 130 million light-years away, this is the only neutron star merger so far seen in electromagnetic radiation and heard in gravitational waves, making it a natural choice for investigating these powerful events.
Killer-nova?
Neutron star merger gamma rays are arguably the most threatening aspect of these events. This is because this type of radiation carries enough energy to strip electrons from atoms, a process called ionization. And this burst of ionizing radiation can easily destroy the Earth’s ozone layer, resulting in our planet receiving lethal doses of ultraviolet radiation from the sun.
Perkins and his colleagues determined that the gamma rays from the neutron star merger – in the twin jets from either side of the merger – would have seriously burned any living matter that fell directly into its path at a distance of 297 light-years. Fortunately, however, that effect has a very small scope. In other words, it would take a “direct hit” from the jet to cause dramatic results. But, there is another problem.
These jets are often accompanied by gamma rays, which would also affect the Earth’s ozone layer if our planet were in a wide orbit – within 13 light years of it. . This “off-axis” gamma-ray cocoon damage to the ozone will also take 4 years to recover from. In total, a gamma-ray cocoon strike would leave the Earth’s surface exposed to harmful ultraviolet light for about half a decade.
Although the gamma-ray effects of neutron star fusion are relatively short-lived, there is also another type of ionizing radiation that causes this emission to be of low energy but long-lasting.
When jets of gamma rays hit the gas and dust surrounding the stars, called the interstellar medium, this creates a powerful X-ray emission called the X-ray afterglow. Such X-ray emissions are longer-lived than gamma-ray emissions and may deplete the ozone layer, the team says. This, therefore, is undoubtedly very dangerous. Earth will need to get very close to this background light before we can worry about our fate, however – within a distance of 16.3 light years to be exact.
And we haven’t even gotten to the worst part yet.
The scariest effect of the neutron star smash-up the team discovered comes from those energetically charged particles, or cosmic rays, that spread far from the epicenter of the event in the form of an expanding bubble. If these cosmic rays were to hit Earth, they would strip the ozone layer and leave the planet vulnerable to long-term ultraviolet radiation. thousands of years.
This would qualify as an extinction-level event, and Earth would be affected even if our planet were 36 light-years away.
“The specific safety distance and the most dangerous part are uncertain as many results depend on properties such as the viewing angle of the event, the energy of the explosion, the mass of ejected material, and so on,” continued Perkins. “With the combination of parameters that we choose, it seems that cosmic rays are the most threatening.”
Again, don’t panic yet!
Before crying that the end is near, it is worth weighing the apocalyptic picture painted by the impact of the neutron star collision against other factors surrounding these events.
“Neutron star mergers are very rare but very powerful, and this, combined with a very small lethality, means the extinction caused by the merger of a binary neutron star should not be a concern for people on Earth,” confirms Perkins.
To get a picture of this anomaly, of all the 100 billion stars in the Milky Way, scientists have so far found one kilonova progenitor system, CPD-29 2176, located about 11,400 light years from Earth.
“There are a few other more common events like solar flares, asteroid impacts, and supernova explosions that have a better chance of being catastrophic,” Perkins continued.
He added that some of these other events were associated with mass extinction events on Earth, the most prominent example of which was the impact of the big sky that wiped out non-avian dinosaurs and a third of life on Earth. 66 million years ago in the Cretaceous-Tertiary extinction event.
Where this research has important implications is in the search for life elsewhere in the universe, as it gives us a glimpse of systems that may not be able to enjoy the conditions necessary to support life. (Life as we know it, at least.)
“Their conclusion that kilonovas can be as dangerous as supernovae, but are more common, is consistent with what I believe to be the case,” said Niels Bohr Institute Cosmic Dawn Center scientist Darach Watson, who also studies kilonovas and did not. involved in this research, he told Space.com. “So, this could be a big threat to planets in old galaxies where star formation is over, not so much in the Milky Way.”
Regarding the research team, Perkins explained that the next step is to see more of these neutron star collision events.
“Currently, we have only one confirmed detection of a kilonova in a neutron star merger, so any additional observations will preclude unknowns,” he concluded.
The team’s research has been published in an open access paper repository arXiv.
