The object called ‘2014-YB35’ is predicted to skim the Earth on Friday travelling at more than 23,000 mph in space.
It is not unusual for small meteorites to pass close by, however one of this size is a very rare occurrence and poses a very real threat, an expert told the Express.
Any impact would trigger devastating changes in the climate, earthquakes and tsunamis.
Bill Napier, professor of astronomy at the University of Buckinghamshire, told the Express there is a "very real risk" of a comet or damaging asteroid hitting Earth.
He said: "With something like YB35, we are looking at a scale of global destruction, something that would pose a risk to the continuation of the planet.
"These events are however very rare, it is the smaller yet still very damaging impacts which are a very real threat."
Experts warn it is only a matter of time before an asteroid capable of "life-altering" damage collides with our planet.
This rock is forecast to pass within 2.8 million miles - a tiny distance in astronomical terms - of Earth on Friday, according to NASA's Near Earth Object Programme.
It is estimated to be from between 500 metres and 1km wide, with 990 metres the most likely.
The object was first spotted by the Catalina Sky Survey at the end of last year with astronomers expected to be closely watching its progress this week.
Credits to Mirror.co.uk