Since September 29, a newcomer has been keeping the Moon company in the sky. It is not a planet, nor a shooting star, but an asteroid which, for two months, will play the role of “second moon”! Olivier Hernandez, astrophysicist and director of the Montreal Planetarium, answered all my questions about this rare phenomenon!
I heard we just inherited a second moon. Can you explain to me what it is?
Of course ! In fact, it’s an asteroid with a funny name: it’s called 2024PT5. It’s a very small asteroid, about the size of a bus. This asteroid is in orbit around the Sun. Around September 29, Earth and the asteroid found themselves in the same place in space, on intersecting trajectories. Due to the attraction of the Earth, this asteroid has been captured and will now revolve around it for about two months. Then, it will leave again to continue its trajectory.
If it’s an asteroid, why are we talking about a moon?
A moon is an object that orbits a planet. In this case, we are talking about a “second moon” because, even if it is an asteroid, it will orbit the Earth for a certain time… and then return to its status as a simple asteroid.
How big is this asteroid compared to our Moon?
This asteroid is 10 meters in diameter. He is very, very small. In comparison, our Moon is nearly 3,500 kilometers in diameter! For this reason, this “second moon” will be very difficult to see, unlike our Moon, which lights up the sky.
Is this the first time something like this has happened?
No ! This is a rare phenomenon, but it can happen. There are many asteroids between the planet Mars and Jupiter. Sometimes there are asteroids that are ejected and go towards the Sun. At this time, they can cross the trajectory of the Earth, as is happening now. The last times such a phenomenon happened were in 2006, 2007 and 2022.
By Clémence Tessier, collaborator
Do you want to know more?
Do you like to understand the news?
Come take a look at lesasdelinfo.com. We also have a whole section for teachers!
An Information Coops initiative supported by the Government of Canada.
