Astronomers Have Discovered Earth’s Latest Quasi-Lunar Moon

The Earth has conscionable added its seventh confirmed quasi-lunar moon. It is 2025 PN7, a mini Apollo-type asteroid detected successful August solely by its brightness, acknowledgment to nan Hawaiian Pan-STARRS 1 telescope.

After analyzing its trajectory, scientists concluded that nan entity maintains a 1:1 resonance pinch nan Earth. In different words, it orbits nan sun astatine nan aforesaid clip arsenic our planet. From a distant perspective, this synchronicity makes it look arsenic if nan Earth is accompanied by a mini asteroid—as if it had an further moon.

Unlike nan moon, quasi-lunar moons are not gravitationally bound to nan Earth. They are ephemeral companions, successful cosmological terms, pursuing their ain way astir nan sun. Only astatine definite times do they travel adjacent capable to look bound. In nan lawsuit of 2025 PN7, its minimum region is 299,000 kilometers, while astatine its farthest constituent it tin scope 17 cardinal km. For comparison, nan satellite remains astatine an mean region of 384,000 km from Earth.

According to nan article published successful Research Notes of nan AAS, nan asteroid has been successful a quasi-satellite shape since 1965, and is expected to stay truthful for 128 years. Some researchers estimate that 2025 PN7 will yet move distant successful 2083.

Why Does nan Earth Have Quasi-Lunar Moons?

So far, 7 bodies person been confirmed that look to travel nan satellite successful its orbit. Astronomers judge that much whitethorn beryllium discovered successful nan future. Earth is simply a earthy reservoir of quasi-lunars because nan Earth's orbit is akin to that of definite adjacent objects that inhabit nan alleged Arjuna group of asteroids, a organization that has only precocious begun to beryllium studied successful greater detail.

The Arjuna group does not shape a ringing for illustration nan asteroid loop betwixt Mars and Jupiter, but comprises a legion of near-Earth rocks that orbit nan sun connected a akin way arsenic our planet. Occasionally, immoderate of these asteroids coincide pinch our trajectory and, depending connected their orbital dynamics, are classified arsenic quasi-lunar aliases mini moons.