NASA Confirms Earth’s New ‘Mini Moon’ Companion: A Tiny Asteroid with a 50-Year Stay
Earth has a new, tiny celestial companion: an asteroid named 2025 PN7, only about 62 feet (19 meters) wide, that will linger nearby for nearly six decades. This discovery, made by sky surveys, reveals a quasi moon, an asteroid that shares Earth’s year and appears to orbit us, though it’s not a true satellite. The Minor Planet Center in Cambridge, Massachusetts, validates these findings and publishes orbital data.
What’s fascinating is that 2025 PN7’s orbit is so similar to Earth’s that it will stay with us until around 2083. This is due to a mean motion resonance, a locked timing that keeps the asteroid’s period the same as Earth’s, despite not being tied to Earth by gravity. The asteroid’s small size and gentle forces, like sunlight, play a crucial role in maintaining this resonance.
But why is this discovery significant? Well, every new quasi moon adds valuable data points for understanding how small bodies move in crowded gravitational neighborhoods. Scientists can use these data points to refine models of stability, close approaches, and safe operating zones for future spacecraft. Moreover, these quasi moons help test Earth’s neighborhood, making them ideal for practicing delicate maneuvers near small bodies.
It’s important to note that 2025 PN7 is not a second moon. Our Moon is gravitationally bound to Earth, while this asteroid orbits the Sun and only shares our year. It won’t affect tides or brighten our night sky, and its faint light keeps it out of reach for backyard telescopes. Additionally, 2025 PN7 is harmless, with its path not bringing it into our atmosphere, and the orbit models already account for normal gravitational tugs.
The study, published in Research Notes of the AAS, highlights the importance of these quasi moons in advancing our understanding of the solar system and space exploration.