A large asteroid, known as 2023 DZ2, will pass safely between Earth and the Moon this weekend, offering scientists a rare opportunity to study a space rock of this size up close. The object, estimated to be between 40 and 90 metres in diameter, is big enough to destroy a city if it were to strike, but there is no risk of collision.
Discovered a month ago, the asteroid will come within 515,000 kilometres of the Moon on Saturday US time, and then fly past Earth several hours later at a speed of approximately 28,000 kilometres per hour. Its closest approach to our planet will be just over 168,000 kilometres away, less than half the distance to the Moon.
According to Nasa, asteroid flybys are common, but it is rare for one so large to come so close; such events occur only about once a decade. The close encounter will allow astronomers to study the space rock using binoculars and small telescopes.
"There is no chance of this 'city killer' striking Earth, but its close approach offers a great opportunity for observations," said Richard Moissl, head of planetary defence at the European Space Agency. Astronomers from the International Asteroid Warning Network are viewing the flyby as a practice run for planetary defence in case a hazardous asteroid is ever discovered.
The Virtual Telescope Project will provide a live webcast of the event. The asteroid is not expected to return until 2026, and scientists have since ruled out any initial concerns that it might hit Earth during that future pass.
