BUSINESS INSIDER
A star is hurtling towards our solar system and
could knock millions of asteroids straight towards Earth
8 January 2017
Researchers have known for a while that a star called Gliese 710 is headed straight for our solar
system, but they've now worked out precisely when it should arrive.
The star is currently hurtling through space at
about 32,000 mph, and is around 64 lightyears away. (One lightyear is
around 5,878,000,000,000 miles.)
Gliese 710 is about half the size of our
sun, and it is set to reach Earth in 1.35 million years, according to a
paper published in the journal Astronomy & Astrophysics
in November.
And when it arrives, the star could end up a
mere 77 light-days away from Earth — one light-day being the equivalent of how
far light travels in one day, which is about 26 billion kilometers, the
researchers worked out.
As far as we know, Gliese 710 isn't set to
collide directly with Earth, but it wil be passing through the Oort Cloud, a
shell of trillions of icy objects at the furthest reaches of our solar system.
So although 77 light-days sounds like a
relatively safe distance, the speeding star could burst through the cloud
and shoot these icy objects and comets all around our solar system. Any one of
these is pretty likely to collide with Earth.
"Gliese 710 will trigger an observable
cometary shower with a mean density of approximately ten comets per year,
lasting for three to 4 million years," wrote the authors.
The team, who hails from Adam Mickiewicz
University in Poland, used measurements from the European Space Agency's
Gaia space observatory.
This new observatory is constructing the
largest and most precise 3D space catalog ever made, totalling approximately 1
billion astronomical objects, which means the data are ten times more accurate
than previous predictions.
There's still an error rate of around 50%
though, which means Gliese 710 could actually scrape past at a mere
40 light-days away.
Some scientists speculate that
a similar event of
a star passing through the Oort cloud triggered the asteroid that wiped out the
dinosaurs around 65 million years ago.
However, the Gliese 710 event could make
the dinosaur extinction look relatively minor. At its closest distance, it will
be the brightest and fastest observable object in the sky, and as the
authors say in the paper, it will be the "strongest disrupting encounter
in the future and history of the solar system."
But it's also not the only galactic body to
worry about. There are
as many as 14 other stars that could come within a 3 light-year distance to us any time
over the next few million years.
Source : BUSINESS INSIDER
