Asteroid 2020SW will pass the Earth at a distance closer than our own weather and TV satellites at 12.13pm tomorrow.
The asteroid the size of a London bus will be just 17,661 miles away when it skims the Earth, much closer than the moon's 238,866 miles and below the 22,300 miles high that satellites orbit.
The asteroid will be over Australia or New Zealand when it makes its closest pass.
The asteroid was spotted by scientists last Friday, and you will be able to watch it as it passes on Virtual Telescope.
Anyone with a six or eight inch telescope may also be able to see 2020 SW as it moves from the constellation of Pegasus into Pisces.
According to EarthSky the satellite is orbiting the sun approximately every 372 days - but won't hit the Earth for at least the next 50 years.
NASA explained that while the chances of 2020SW hitting the earth are very low, it does have contingency plans if an asteroid were found to be on a collision course.
A spokesman said: “One of the techniques suggested for deflecting an asteroid includes nuclear fusion weapons set off above the surface to slightly change the asteroid’s velocity without fracturing it.
“High speed neutrons from the explosion would irradiate a shell of material on the surface of the asteroid facing the explosion. The material in this surface shell would then expand and blow off, thus producing a recoil upon the asteroid itself.
“A very modest velocity change in the asteroid’s motion (only a few millimeters per second), acting over several years, can cause the asteroid to miss the Earth entirely. However, the trick is to gently nudge the asteroid out of harm’s way and not to blow it up.
“This latter option, though popular in the movies, only creates a bigger problem when all the pieces encounter the Earth.
“Another option that has been discussed includes the establishment of large solar sails on a small threatening object so that the pressure of sunlight could eventually redirect the object away from its predicted Earth collision.”
