Quick Read
- NASA confirmed asteroid 2025 PN7 as Earth’s new quasi-moon, discovered in August 2025.
- 2025 PN7 orbits the Sun in sync with Earth, not as a true moon.
- The asteroid is about 19 meters wide and will remain near Earth until 2083.
- It poses no threat, staying millions of miles away from our planet.
- Scientists believe its presence helps study the solar system’s formation.
What Is Earth’s ‘Second Moon’? NASA’s Quasi-Moon Discovery Explained
For over sixty years, Earth has had an unnoticed companion, quietly moving alongside us in the vast expanse of space. In August 2025, astronomers at the University of Hawaii spotted a tiny asteroid—now officially named 2025 PN7—during a routine telescope survey. This discovery, later confirmed by NASA, has sparked intrigue among scientists and the public alike: has Earth suddenly acquired a second moon?
To answer that, let’s step back and examine what 2025 PN7 really is. Unlike our familiar Moon, which is gravitationally bound to Earth and orbits it every 27 days, 2025 PN7 doesn’t revolve around our planet in the same way. Instead, this asteroid orbits the Sun, but its path closely tracks Earth’s own orbit, creating the illusion that it is shadowing our planet. As Dr. Alfredo Carpineti, science writer for IFLScience, puts it, “2025 PN7 is a quasi-moon, not a true moon.” Think of it as a car driving in a parallel lane on a cosmic highway—always nearby, but never merging.
How Did Scientists Find 2025 PN7?
Spotting an object as small as 2025 PN7 is no small feat. Measuring only about 62 feet (roughly 19 meters) across, it’s dwarfed by the Moon and even by many other asteroids. Its faint brightness and diminutive size meant it stayed hidden for decades, only revealing itself as a tiny speck against the stars during a careful survey. Once noticed, researchers combed through archival data and realized this rock had slipped into its quasi-moon orbit as far back as 1957.
NASA’s simulations predict that 2025 PN7 will keep pace with Earth until about 2083. In cosmic terms, this is a fleeting visit—just 126 years of companionship before the asteroid drifts off into deeper space. During this time, it will approach as close as 2.5 million miles, about ten times the distance between Earth and the Moon, and swing out as far as 17 million kilometers (roughly 11 million miles) thanks to the competing gravitational pulls of the Sun and neighboring planets (Metro, LADbible).
Quasi-Moons vs. True Moons: What’s the Difference?
The term “quasi-moon” might sound like science fiction, but it’s a real classification in astronomy. Quasi-moons are space rocks that appear to orbit Earth but aren’t truly captured by its gravity. Instead, they follow the Sun on a path very similar to ours, lingering nearby for decades or even centuries. By contrast, “mini-moons” are short-lived objects that actually orbit Earth, sometimes for only a few months before escaping.
Earth has had at least eight known quasi-moons over the years, including objects like Kamoʻoalewa and 2023 FW13. What sets 2025 PN7 apart is its longevity; it may become the longest-lived quasi-moon ever recorded. Scientists believe its presence offers a valuable chance to study how small asteroids interact with planetary gravity, potentially shedding light on the early days of our solar system, when rocky fragments jostled for position and planets formed in a chaotic dance (Dagens).
Is 2025 PN7 a Threat to Earth?
Whenever news of an asteroid surfaces, it’s natural for concerns to arise. After all, headlines about “city-killer” asteroids have stoked public anxiety before. But experts are quick to reassure: 2025 PN7 poses absolutely no danger to Earth. It will never come close enough to enter our atmosphere or threaten impact. Its closest approach is still millions of miles away, far beyond even the orbit of our Moon.
Dr. Carpineti puts it simply: “It’s a tiny space rock we have sort of picked up on our cosmic journey.” And while it’s highly unlikely that amateur stargazers will be able to spot the visitor without specialized equipment, there’s something quietly comforting about having an extra passenger on our annual trip around the Sun.
Why Do Quasi-Moons Matter?
Beyond the novelty, quasi-moons like 2025 PN7 offer scientists rare opportunities to study the subtle gravitational interplay between planets and small asteroids. Each discovery adds a piece to the puzzle of our solar system’s evolution. By observing these objects, researchers gain insight into how planetary bodies shape the paths of their neighbors—clues that help reconstruct the chaotic environment of our solar system’s youth.
Moreover, quasi-moons are reminders of how busy and dynamic space truly is. Their presence highlights the ever-changing nature of our cosmic neighborhood. As Dr. Carpineti notes, “It’s always fun finding a new quasi moon. It shows just how busy the bulk of space is.”
The Road Ahead: What Happens After 2083?
According to NASA’s current models, 2025 PN7 will eventually break free from its quasi-moon status around 2083. After decades of quietly trailing Earth, it will drift off into the void, joining the countless other asteroids roaming the solar system. Its departure will be unremarkable from a human perspective—no fireworks, no visible change in the night sky.
Yet the story of 2025 PN7 will remain a testament to the power of observation and the curiosity that drives scientific discovery. Each new finding, no matter how small or fleeting, expands our understanding of the universe and our place within it.
So, does Earth now have two moons? Technically, no. Our singular, brilliant Moon remains the only natural satellite locked in Earth’s embrace. But for the next several decades, we have a cosmic companion—a quasi-moon—traveling alongside us, a silent witness to our journey around the Sun.
NASA’s confirmation of 2025 PN7 as Earth’s temporary quasi-moon underscores the dynamic complexity of our planetary neighborhood. While its stay is brief on the cosmic calendar, its discovery offers a unique window into the gravitational dance between Earth and the myriad space rocks that cross our path, reminding us how much more there is to learn about the hidden rhythms of the solar system.