The universe has numerous stars and some of them are closer to us than the others. The threat of collision with any of these has been a burning question in scientists mind for a long time. Recently, the scientists have found that a star is closing on us and declared it as a potential threat.
There’s a 90 percent chance that the nearby star will approach Earth within the next half million years. Known as Hipparcos 85605, the stellar dwarf is currently 16 light years away from us, and it could come as close as 0.13 light years.
To hunt for close encounters of this stellar kind, Coryn Bailer-Jones of the Max Planck Institute for Astronomy modelled the past and future motion of 50,000 stars using data from the European Space Agency’s Hipparcos satellite, which scanned the sky in the 1990s. He found 14 stars that pass us at a distance of 3.26 light years. And four stars will pass at a distance of 1.6 light-years of the sun.
Of these, the closest encounter appears to be HIP 85605, which is either a K star (an orange dwarf) or an M star (a red dwarf) in the constellation Hercules. The star has a 90 percent probability of coming between 0.13 and 0.65 light years between 240,000 and 470,000 years from now. The next closest will be Gliese 710, a K7 dwarf that’s about 63 light years away right now in the constellation Ophiucus. This stellar dwarf has a 90 percent probability of coming within 0.32 to 1.44 light years in about 1.3 million years.
While HIP 85605 and GL 710 pose no direct collision danger, their gravitational forces could, however, scatter comets out of the Oort Cloud in our outer solar system, sending them careening inwards in our direction. "I think we can safely predict that comet orbits would indeed be disrupted by the closest encounters," Bailer-Jones tells. He’ll be following-up with the probability of the Earth being hit by a comet strewn by a passing star. A larger perturbation may have been caused by gamma microscope, he writes, a G6 giant that came within 1.14 to 4.37 light years around 3.8 million years ago.
And will any of these stars bring along their pack of exoplanets? Likely, but they won’t be close enough for us to visit. According to Bailer-Jones, their fast speed, as they swing by the sun, would make reaching those planets as difficult as travelling to more distant star systems. He also cautions that some of the stars simulated have ‘questionable data,’ so these estimations could be slightly off. “This study is limited to stars for which we have accurate distances and velocities; which, in turn, limits us to stars currently within a few tens of light years from the Sun,” Bailer-Jones tells Forbes. His calculations show that 42 stars have or will come within an estimated 6.4 light years from the sun over a time-frame spanning 20 million years in the future.