Earth's Moon Count Timeline: from Ancient Luna to Modern Mini-Moon Discoveries
By Sarah Jenkins
Wide-field survey operations, such as the Catalina Sky Survey in Arizona and the Pan-STARRS telescope in Hawaii, have cataloged an extraordinary cross-section of temporary visitors and long-term co-orbital objects over the past three decades.
| Object Designation | Discovery Year | Classification | Orbital Behavior & Lifespan |
|---|---|---|---|
| Luna | Prehistoric | Major Natural Satellite | Permanent, stable geocentric orbit for ~4.5 billion years. |
| 3753 Cruithne | 1986 | Co-Orbital Companion | 1:1 orbital resonance; tracks a horseshoe path relative to Earth. |
| 2006 RH120 | 2006 | Temporarily Captured Orbiter | Circled Earth four times over 13 months before escaping in 2007. |
| 2010 TK7 | 2010 | Earth Trojan Asteroid | Locked into the Sun-Earth L4 Lagrange point ahead of Earth. |
| 469219 Kamoʻoalewa | 2016 | Quasi-Satellite | Stable co-orbital state lasting ~300 years; possible lunar fragment. |
| 2020 CD3 | 2020 | Temporarily Captured Orbiter | Remained in chaotic geocentric orbit for roughly 3 years before departure. |
| 2024 PT5 | 2024 | Temporarily Captured Flyby | Executed a two-month horseshoe-like capture loop before returning to solar orbit. |
Sarah Jenkins is a veteran tech journalist with over 12 years of experience covering artificial intelligence, mobile innovations, and digital ethics. Her insights have appeared in leading technology publications worldwide.
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