68 giant asteroids are on course to hurtle close to Earth before the end of February, according to latest NASA space data.
Some are more than 1km wide and threaten devastating consequences if they were to strike our planet.
Of almost 70 asteroids on the radar most are around 100 metres wide, the size of a double decker bus, and would be capable of causing significant damage.
Experts warn if one of these monsters, some of which travel at up to 70,000 miles an hour, were to hit Earth it could “alter life as we know it”.
Plumes of debris thrown into the atmosphere would change the climate making the planet inhabitable for all life including humans.
Bill Napier, professor of astronomy at the University of Buckinghamshire, said: “If you are talking about a real major impact you are looking at one every few centuries, these are the real show stoppers and in history have sometimes been described as fire from the heavens.
“However the smaller collisions happen more frequently, asteroids of 2km (1.2 miles) can cause a global catastrophe which would exterminate around two thirds of the human race.