The End of Planet Earth is in Sight but not for a few Million Years - More than 20 Stars are Heading Towards our Solar System, and Could Cause Devastating Comet/Asteroid Strikes that would likely Destroy Life on Earth

Astrogeology, Asteroids, Robots, Space Flight & Extraterrestrial Matters

Fagharifard reported in 2017 within the next million years or so, between 19 and 24 stars will come within 3.26 light years of our sun. This is close enough to deflect comets away from there original paths and towards Earth - increasing the chance that one will wipe out life on our planet. This is according to a new paper that has looked at how often stars stray into the Oort cloud - a spherical shell of billions of icy objects that exist in the outer reaches of our solar system. A particularly close encounter of one star, dubbed Gliese 710, in 1.3 million years' time, stands out. It is predicted to pass within just 2.3 trillion km or about 16,000 Earth–sun distances, well within the Oort Cloud. Part of the Sepens Cauda constellation, Gliese 710 currently sits some 64 light-years away. It's travelling in our direction though, and is expected to come within 1.2 trillion miles of Earth. Although a significant distance, this is still close in space terms as Alpha Centauri, currently the closest star to Earth beyond our sun is some 25.67 trillion miles away. The consequences of this passing star are so big, it's been deemed one of the biggest threats to Earth over the next 10 million years, aside from the odd comet or asteroid already heading our way, which we are now taking steps to defend against.

'Certainly anything coming within that distance you should worry about,' said Coryn Bailer-Jones, of the Max Planck Institute for in Heidelberg and the paper's author told the Guardian.  If this occurs, the strong gravitational force of the star, which has a mass 60 per cent that of our sun, could cause a shower of comets to switch course and target our planet. Although some will drift into space and others will be absorbed by the sun and other planets, astronomers have warned a significant impact with Earth is entirely possible. A further 490 to 600 stars will pass the sun within a distance of 16.3 light years within the next million years, the paper claims. 

The latest calculations of such stars comes from movements of more than 300,000 stars surveyed by ESA's Gaia satellite.  As the solar system moves through the Galaxy, and as other stars move on their own paths, close encounters are inevitable – though 'close' still means many trillions of miles. A star, depending on its mass and speed, would need to get within about 37 trillion miles (60 trillion kilometres) before it starts to have an effect on the solar system's distant reservoir of comets, the Oort Cloud, which is thought to extend out to 15 trillion kilometres from our sun, 100,000 times the Sun–Earth distance.