It's Confirmed: Earth Now has Two Moons
In recent weeks, you may have come across news suggesting that Earth was set to gain a second moon. We can now officially confirm that Earth has indeed acquired a second moon following the capture of asteroid 2024 PT5
Asteroid 2024 PT5
On Sunday, September 29, our planet captured a tiny asteroid named 2024 PT5, transforming it into a temporary mini-moon.
This fascinating occurrence was first observed by astronomers at the Complutense University of Madrid. Richard Binzel, an astronomer at the Massachusetts Institute of Technology (MIT), provided some insights into these celestial visitors.
“These events happen with some frequency, but we rarely see them because they’re very small and difficult to detect,” Binzel explained. “Only recently has our survey capability advanced to the point where we can spot them routinely.”
The team from Complutense University identified the small space rock in August using a powerful telescope based in Sutherland, South Africa.
So, What Exactly are Mini-Moons?
Mini-moons, such as 2024 PT5, are small asteroids that Earth’s gravity captures temporarily, allowing them to orbit our planet before moving on. Typically, these little asteroids travel around the sun like their counterparts, but when they come close enough to Earth, our gravitational pull can draw them into a brief orbit. Their stay is usually short-lived; they may linger for a few weeks or months before breaking free and resuming their journey through the solar system.
Scientists are particularly intrigued by mini-moons because they provide an opportunity to study near-Earth objects up close, enhancing our understanding of how our solar system operates.
Journey of 2024 PT5
According to data from NASA’s Jet Propulsion Laboratory Horizons system, the stay of this mini-moon will be short-lived. The temporary capture began at 3:54 p.m. EDT on September 29, 2024, and is set to end at 11:43 a.m. EDT on November 25, 2024.
So, Where did This Little Visitor Originate?
2024 PT5 belongs to the Arjuna asteroid belt, a collection of space rocks that have orbits similar to Earth's, located about 93 million miles from the sun. Some objects from the Arjuna asteroid belt can come close to Earth, approaching at distances of around 2.8 million miles and travelling at relatively low speeds of less than 2,200 miles per hour.
“Asteroid 2024 PT5 won’t complete a full orbit around Earth. You could think of it this way: if a true satellite is like a customer making purchases inside a store, then objects like 2024 PT5 are merely window shoppers,” explained Carlos de la Fuente Marcos, a professor and mini-moon expert from the Complutense University.
How Common are Captures Like 2024 PT5?
While it may seem remarkable for Earth to gain a second moon, gravitational captures like this are more common than you might think. Scientists have documented two previous “short captures,” which typically last about a week and are estimated to occur several times per decade. Additionally, there have been two rarer “long-capture” events.
After its brief visit, 2024 PT5 will resume its orbit around the sun as part of the Arjuna family of asteroids. Although it won’t linger for billions of years like our primary moon, its transient presence highlights the dynamic nature of our cosmic neighbourhood.
Not Currently Visible
You may be curious if you can spot this mini-moon in the night sky. Unfortunately, it’s too small and dim for most observers. 2024 PT5 falls outside the visibility range of typical amateur telescopes and binoculars. However, it is detectable with professional-grade equipment. Observing this object requires a telescope with a diameter of at least 30 inches, equipped with a CCD or CMOS detector; a 30-inch telescope paired with the human eye alone won’t suffice.
Comparing 2024 PT5 to Our Moon
To put its size in perspective, our moon has a diameter of about 2,159 miles, whereas 2024 PT5 is estimated to be just 37 feet wide. This means our moon is over 300,000 times larger than this tiny asteroid!
What Happens Next?
As 2024 PT5 continues its journey, we’ll keep our eyes—and telescopes—on the skies. After all, who knows when the next mini-moon might make an appearance?
With advancements in technology, we may soon be able to study these transient visitors more closely. Who knows? One day, we might even launch missions to gather samples or test new spacecraft.
For now, Earth will enjoy the company of this tiny companion orbiting our planet. Let’s take a moment to appreciate the marvels of our ever-changing universe and the surprises it has in store for us.
