Saturday’s close encounter will offer astronomers the chance to study a space rock from just over 168,000km away.
That’s less than half the distance from here to the moon, making it visible through binoculars and small telescopes.
Scientists estimate its size somewhere between 40 metres and 90 metres.
Discovered a month ago, the asteroid known as 2023 DZ2 will pass within 515,000km of the moon on Saturday and, several hours later, buzz the Indian Ocean at about 28,000km/h.
“There is no chance of this ‘city killer’ striking Earth, but its close approach offers a great opportunity for observations,” the European Space Agency’s planetary defence chief Richard Moissl said in a statement.
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Astronomers with the International Asteroid Warning Network see it as good practice for planetary defence if and when a dangerous asteroid heads our way, according to NASA.
The Virtual Telescope Project will provide a live webcast of the close approach.
The asteroid won’t be back our way again until 2026.
Although there initially seemed to be a slight chance it might strike Earth then, scientists have since ruled that out.