Wandering Star could bring a comet shower to Earth in about a million years, full details here

One of the most pop­u­lar dooms­day movie themes is a giant aster­oid head­ing towards Earth that was acci­den­tal­ly spot­ted by a sci­en­tist. Comets with con­spic­u­ous­ly long tails are rather huge objects of ice and earth orbit­ing the Solar Sys­tem in a large sphere called the Oort Cloud. But in the fic­tion­al cat­a­stro­phe sce­nar­ios they are rarely seen as a dan­ger. But this could change in the dis­tant future, as a wan­der­ing star could rain down mil­lions of comets on Earth in what could very well be called a future doomsday.

Cur­rent­ly, Prox­i­ma Cen­tau­ri is con­sid­ered the clos­est star to Earth apart from the Sun. It is about 4.25 light-years away. But we live in a dynam­ic galaxy that is con­stant­ly chang­ing, and so Earth could have a new stel­lar neigh­bor that will be much clos­er to home in about a mil­lion years.

For about 20 years, sci­en­tists have known about a tiny star called Gliese 710 in the Ser­pus Cau­da con­stel­la­tion, locat­ed 62 light-years from Earth. A 2018 study states that Gliese 710 is mov­ing direct­ly toward our solar sys­tem and is pro­ject­ed to be with­in 0.06 light-years of Earth in about 1.29 mil­lion years. Seen cos­mi­cal­ly, this dis­tance is appar­ent­ly only a hair’s breadth.
For­tu­nate­ly, at this dis­tance, the Star Gliese 710 will not pose a threat to life on Earth at this time. How­ev­er, at such a short dis­tance, the Star Pass could still wreak havoc.

When Gliese 710 pass­es the Oort Cloud in 0.06 light-years, it will dis­rupt mil­lions of comets and eject them into space. Many of them will be aimed at the inner solar sys­tem. This could spell doom for Earth as these comet show­ers would put aster­oids to shame.

Accord­ing to Pro­fes­sor Brad Gib­son, comets would cause much more dam­age on Earth com­pared to aster­oids of the same mass. Gib­son is Direc­tor of the EA Milne Cen­ter for Astro­physics at the Uni­ver­si­ty of Hull. He found that such cometary impacts occurred more fre­quent­ly in the ear­ly phas­es of plan­e­tary for­ma­tion. The rea­son for the event that wiped out most species on Earth 65 mil­lion years ago has long been debat­ed, whether it was a comet or an aster­oid that made it hap­pen. A con­sen­sus was lat­er reached that it was an aster­oid, but there are still con­cerns about Earth­’s future.

A sun-like star enter­ing the solar sys­tem and slow­ly migrat­ing through the Oort cloud of comets is a rare event, occur­ring only once in a mil­lion years. This event will dis­rupt more than ten mil­lion comets expect­ed to rain down on the inner solar system.