This month, Earth will temporarily have a second moon. It’s a rare event that will last for about two months before this mini-moon continues on its journey through space.
Key highlights:
- Earth will have a temporary second moon, named 2024 PT5, from 29 September to 25 November.
- The asteroid comes from the Arjuna asteroid belt and will orbit Earth for just a short time.
- These mini-moon events are rare and fascinating for scientists who study space rocks.
Second moon to orbit Earth until this date
The asteroid, 2024 PT5, was recently discovered by astronomers and is set to circle our planet until 25 November 2024.
Unlike our usual moon, which has been around for over 4 billion years, this mini-moon will stick around for just a couple of months before heading back into space.
Carlos de la Fuente Marcos, a professor and expert in asteroid behaviour, explained that 2024 PT5 belongs to a group of space rocks known as the Arjuna asteroid belt.
These asteroids follow a path around the sun that is quite similar to Earth’s orbit, which means that every so often, one of them gets close enough for Earth’s gravity to pull it into orbit temporarily.
Marcos mentioned that these asteroids must come quite close to Earth – within around 2.8 million miles (4.5 million km)– and move at a slow speed of about 2,200 miles per hour (3,540 km/h) to become a mini-moon.
When these conditions are met, Earth’s gravity can capture them, turning them into a mini-moon for a short while.
Why is this significant?
Mini-moon events like this one aren’t common, and they provide an excellent opportunity for scientists to study how asteroids behave when captured by Earth’s gravity.
According to Marcos, there have been only two known long-term mini-moon events and three short-term ones, including this one.
The most recent mini-moon event before 2024 PT5 was the asteroid 2020 CD3, which remained in Earth’s orbit for several years.
What makes this new event special is that it offers a chance for astronomers to observe an asteroid’s behaviour in real time as it enters and exits Earth’s orbit.
However, unlike our primary moon, this mini-moon will not be visible to most of us.
Marcos explained that the 2024 PT5 is too small and dim to be seen with regular telescopes or binoculars.
Only professional astronomers with powerful telescopes will be able to observe this mini-moon as it orbits Earth.
The gravitational pull of the sun will eventually push 2024 PT5 out of Earth’s orbit, sending it back into space.
After 25 November, this asteroid will return to its path around the sun as part of the Arjuna asteroid belt.
