Earth set to become a two moon planet

Earth is set to become a two moon planet for the next couple of months as a 10 metre wide asteroid - officially known as 2024PT - will begin orbiting the planet.

University of Auckland Astrophysicist Professor Nick Rattenbury told Afternoons that it will start doing a loop-de-loop around Earth from 29 September.

"A moon is typically the term that we give to a world which is orbiting in a fairly stable orbit around a parent body, like our own Moon going around the Earth, or something like Io going around Jupiter," he said.

"It's going to become a satellite of Earth, like Earth's Moon, around the Earth, starting September 29, and it's going to hang around for just over 56 and a half days before heading on its way, being flung out again, and going back onto its orbit out to where it came from.

"So it's not a permanent Moon. It's visiting us for a couple of months, and then it's going to go head back out to where it came from."

However, it will be hard to see, Professor Rattenbury said.

"This is a small chunk of rock, so you could see it, but you'd need to have a good telescope."