An asteroid the size of a bus will make a close fly-by of the Earth on Saturday.
The object, dubbed 2019 GF1, is between 8m and 18m long and will come as close as 1.8 million kilometres from the planet, data from NASA's Jet Propulsion Laboratory (JPL) revealed.
For a typical object, it's travelling relatively slowly at 1.91km/s – about five times the speed of sound – according to JPL.
"It's moving across the sky very slowly because it's orbiting the Sun at a similar rate to the Earth," South African Astronomical Observatory (SAAO) Science Engagement Astronomer Dr Daniel Cunnama told News24.
Even at 18m long, 2019 GF1 is smaller than 2019 GC6 which came very close to Earth on April 9.
Massive size
Asteroid 2019 GC6 was only discovered nine days before its fly-by, reports Space.com, and is a massive 30m wide.
It came as close as 219 000km. The Moon averages 380 000km from Earth.
Asteroids usually orbit a belt between Mars and Jupiter, as well as beyond Neptune in a region known as the Kuiper Belt.
They can be nudged out of orbit by an impact or the gravity of a large object.
These objects can then make their way into the inner solar system (between the Sun and Mars) where they are known and near-Earth objects (NEOs).
Cunnama remarked that 2019 GF1's orbit was close to that of Earth.
"It looks like it's on a very big orbit. It's slightly off the Earth's orbit."
2019 GF1's orbit is shown crossing that of Earth. (NASA JPL)
2019 GF1 could be classified as an Apollo asteroid because it crosses the Earth's orbit, according to JPL data.
Other classifications include Amors (which orbit outside the Earth's orbit), and Inner Earth Objects (which orbit between the Earth and the Sun).
According to Spaceweather.com, there are about 1 967 potentially hazardous NEOs and scientists continue to discover new ones.
The SAAO hosts an Asteroid Terrestrial-Impact Last Alert System (Atlas) instrument in Sutherland to monitor for hazardous asteroids.
The instrument is funded by NASA and costs $3.8m.
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