Weird space phenomena that can kill

Earth is far from free from astronomical influences. As telescopes scan the skies for potentially dangerous asteroids – and NASA tests planetary defence methods – scientists study space weather phenomena that could take out our power grids and communications. However, these are far from the most monstrous and deadly things that the cosmos might be able to throw at us, with physicists having proposed a range of weird and deadly space phenomena that can strike without warning. Fortunately, the chances of them striking are all infinitesimal, and definitely not worth losing sleep over – but, by studying them, scientists can learn more about the universe, its origins, and perhaps even the history of life here on Earth.When suitably massive stars reach the end of their lives and run out of fuel, they collapse under their own mass, forming a black hole.This process, however, releases a tremendous amount of energy in the form of gamma radiation, which shoots out along the star’s axis in opposite directions – much like beams from a lighthouse here on Earth.Gamma ray bursts are much more powerful than a lighthouse beacon, however, being capable of releasing more energy in one shot than our Sun will emit in its entire lifetime.According to the European Space Agency (ESA), ‘Some theories suggest that anything caught in the beam, out to a distance of around 200 light years, will be vaporised.’More conservative estimates suggest that, should a gamma ray burst hit Earth, it would administer lethal levels of radiation to one side of the planet, while destroying the ozone layer and leaving us vulnerable to ultraviolet rays from our own Sun.Over-exposure to ultraviolet radiation causes damage to the DNA in skin cells – leading to genetic defects that can result in premature ageing and skin cancer.Astronomers also believe that shorter bursts of gamma rays can be released when the orbits of pairs of neutron stars – which are often found as binary systems – decay, causing them to smash together in a violent, energy-releasing collision. In some theories, gamma ray bursts vaporise anything in their beam 200 light years from their source (Image: Getty Images) An artist’s impression of a massive star collapsing into a black hole and emitting a gamma ray burst (Image: Nicolle Rager Fuller / NSF)ESA astronomer Norbert Schartel said: ‘There are a lot of supernova remnants in our galaxy, so I suspect that most probably there have been several gamma ray bursts as well.’The good news is that scientists do not think there are any stars within 200 light years of Earth that are destined to go supernova.The ESA added: ‘We do not expect to witness such an event at close range!’Even if there were, the effects would also not be felt unless the Earth was directly in the line of fire of the given star’s axis – making the risk to us much smaller.However, gamma ray bursts close enough to have some impact on Earth are thought to occur every 5 million years or so – meaning that the planet has likely weathered around 1,000 in its lifetime.READ MORE: Thousands expected in Florida to watch Artemis I despite night launch Pictured: Gamma ray bursts are emitted in opposite directions, like beams from a lighthouse (Image: NASA / Swift /Mary Pat Hrybyk-Keith / John Jones)In a paper published last month on the arXiv repository, astronomer Ian Brunton of the University of Illinois Urbana-Champaign and his colleagues propose that certain types of supernovae may have another deadly trick up their sleeve.If a star going supernova is surrounded by a dense cloud of dust and gas, interactions between the gamma rays and other photons emitted in the explosion and this ‘circumstellar medium’ also releases X-rays that could be lethal from up to 160 light years away.If such were to occur in relative proximity to the Earth, it might take months or even years for the X-ray emissions to reach us.When they did, however, they also would deplete the ozone layer, allowing harmful ultraviolet radiation from the Sun to reach the Earth’s surface. Black holes are regions of spacetime so deformed by mass nothing can escape their gravity (Image: Express.co.uk)Scientists think that Earth has been influenced to some degree by supernovae in the past.Relatively undecayed traces of the radioactive isotope ⁶⁰Fe – which has a half-life of 2.6 million years – have been found in ocean sediments dating back 2–3 million years, and therefore may have originated from space via nucleosynthesis in a supernova explosion.Furthermore, the Solar System lies within an area of space known as the ‘Local Bubble’, a hot, low-density region of space thought to have been the result of numerous nearby supernova explosions around 20 million years ago.Mr Brunton and his colleagues said: ‘Combining these findings with our threat assessment here, it is possible that one or more of these supernovae were interacting, and thus inflicted a high dosage of X-ray radiation on Earth’s atmosphere.’This would imply that supernova X-ray emission has had a notable impact on Earth, and potentially played a role in the evolution of life itself.’DON’T MISS:Ukraine sent US air defence systems to annihilate Putin’s missiles [INSIGHT]Ofgem accused of being ‘too slow to act’ as millions foot 2.7bn bill [ANALYSIS]Thousands of households across 14 UK regions plunged into darkness [REPORT] James Webb Space Telescope should be able to detect signals of primordial black holes, if they exist (Image: Getty Images)Our final interstellar nasty is perhaps the most speculative – yet by far the most sinister.Black holes are regions where the very fabric of spacetime is so warped by concentrated mass that, beyond their ‘event horizon’, nothing – not even light – can escape their gravity.In the conventional understanding of cosmic history, black holes were unable to form in the early universe – and only appeared, formed in the wake of supernova explosions, after the first generation of ancient stars had died.However, a theory first proposed by the Soviet physicists Yakov Borisovich Zel’dovich and Igor Dmitriyevich Novikov in 1966 and developed by Stephen Hawking and his colleague Bernard Carr in the mid-seventies suggests that black holes could have formed relatively soon after the Big Bang.Fluctuations in the density of the early universe, they argued, may have given regions of space enough mass to collapse in on themselves to form ‘primordial’ black holes.While controversial, this theory does have its attractive points. For instance, it might explain where all the ‘dark matter’ is – the missing material needed to account for the discrepancy between the universe’s visible matter and the observed motion of the stars and galaxies.Furthermore, primordial black holes, some researchers have argued, could have provided the gravitational kernels around which the first stars and galaxies formed – and also account for the excess of infra-red radiation that astronomers have detected coming from various distant sources across the universe.If they do exist, we should soon be able to find out – thanks to NASA’s new James Webb Space Telescope and the ESA’s upcoming LISA gravitational wave detector, both of which should be able to pick up signals from primordial black holes.Theoretical physicist Professor Avi Loeb of Harvard University said: ‘Primordial black holes could make up a fraction of the dark matter in the universe.’They could kill people by passing through their bodies, but the chance of that is miniscule.”Primordial black holes would have evaporated by now through Hawking radiation if they had less mass than a kilometre-size asteroid.'(Hawking radiation is a mechanism by which black holes, counterintuitively, can lose mass. It relies on one part of a particle–antiparticle pair – which form spontaneously in space – being captured on the threshold of the black hole’s event horizon while the other escapes.)A 2021 study by physicist Professor Sohrab Rahvar of Iran’s Sharif University, Prof. Loeb noted, found ‘that a primordial black hole of asteroid mass just above the Hawking evaporation threshold should not have collided with Earth during its lifetime.’If a primordial black hole did whizz through your body – and that, given the odds against, would truly make you the most unlucky person ever – its passage would take only 0.01 milliseconds.However, in that time, it could cause you to shrink by several inches – causing severe damage to your internal organs – while also burning your innards along its path thanks to its release of high-energy photons as it accreted matter.Death would be immediate, and thoroughly unexpected. But what of the rest of the planet?Prof. Loeb said: ‘The horizon size of asteroid-scale primordial black holes is as small as the size of a proton and their surgical passage through Earth would generate seismic waves, but leave no major collateral damage.’Given this, he quipped, ‘insurance companies should not consider listing primordial black holes among the natural disasters they cover!’