FOUR asteroids will skim past Earth tomorrow in a series of close flybys, according to Nasa.
The space rocks are travelling up to 57,000mph and the largest of the bunch is as tall as the Empire State Building.
Nasa has classed the asteroids as "near-Earth objects" (NEOs) and is keeping them under constant supervision.
Tens of thousands of NEOs are tracked by scientists to ensure they don't collide with our planet. One small change to their trajectories could spell disaster for our planet.
The first of Saturday's asteroids is called 2020 GM1.
It will pass Earth at around 7.15am BST at a distance of 2.3million miles - around nine times the distance between Earth and the Moon.
That may sound far, but it's relatively close in space terms: Nasa considers anything passing within 120million miles of Earth a NEO.
The first of tomorrow's asteroids is also the fastest, clocking speeds of 57,000 miles per hour.
At 1,246ft long, the largest, 2004 FG11, is as big as the Empire State Building.
Astronomers are currently tracking nearly 2,000 asteroids, comets and other objects that threaten our pale blue dot - and new ones are found every day.
What's the difference between an asteroid, meteor and comet?
Here's what you need to know, according to Nasa...
Earth hasn't seen an asteroid of apocalyptic scale since the space rock that wiped out the dinosaurs 66million years ago.
However, smaller objects capable of flattening an entire city crash into Earth every so often.
One a few hundred feet across devastated 800 square miles of forest near Tunguska in Siberia on June 30, 1908.
Luckily, Nasa doesn't believe any of the NEOs it keeps an eye on are on a collision course with our planet.
That could change in the coming months or years, however, as the space agency constantly revises objects' predicted trajectories.
"Nasa knows of no asteroid or comet currently on a collision course with Earth, so the probability of a major collision is quite small," Nasa says.
"In fact, as best as we can tell, no large object is likely to strike the Earth any time in the next several hundred years."
Even if they were to hit our planet, the vast majority of asteroids would not wipe out life as we know it.
"Global catastrophes" are only triggered when objects larger than 3,000 feet smash into Earth, according to Nasa.
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In other news, it recently emerged that an asteroid obliterated early human civilisations in a catastrophic collision with Earth 13,000 years ago.
Scientists recently discovered a "Super-Earth" 31 light-years away that humans could one day colonise.
And, distant planets may host even more life than we have here on Earth, according to one shock study.
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