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Whenever astronomers observe thing caller moving done our portion of space, similar an interstellar entity oregon an antithetic asteroid, idiosyncratic determination claims it could beryllium an alien interstellar abstraction probe. It's similar 1 of those laws astir quality behaviour – Godwin's Law for illustration – that should astir apt person its ain name.
This applies to the detection of 1991 VG, an asteroid with an Earth-like orbit discovered by the Spacewatch Project successful 1991. Astronomers present cognize that it's conscionable an asteroid, and they've besides recovered others similar it.
Together, they're called the Arjuna asteroids and they're Near-Earth Objects (NEO). There's much than 100 of them and they represent the alleged Arjuna secondary asteroid belt.
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Now the Arjuna radical has 1 much member: Arjuna 2025 PN7. It's find is presented successful a caller probe enactment successful Research Notes of the American Astronomical Society titled "Meet Arjuna 2025 PN7, the Newest Quasi-satellite of Earth." The authors are Carlos de la Fuente Marcos and Raúl de la Fuente Marcos, some from the Universidad Complutense de Madrid, Ciudad Universitaria.
When 1991 VG was discovered, it followed a way precise akin to Earth's and remained adjacent to it. That's what led to the 'alien abstraction probe' thinking. But it was truly conscionable the archetypal subordinate of a recently discovered people of objects. That lone became evident erstwhile much were discovered, and present the earthy mentation has eliminated the speculation.
The Arjuna asteroids are known arsenic quasi-satellites. That's due to the fact that portion they determination successful resonance with Earth, they're not gravitationally bound. Sometimes 1 of the Arjuna asteroids is captured by the Earth for a little play of clip and becomes a mini-Moon.
"The Arjunas with the astir Earth-like orbits tin acquisition impermanent captures arsenic mini-moons of our planet," the authors write. That happened with the Arjuna asteroid 2024 PT5, which was captured by Earth and posed a tiny menace of interaction for a while.
"Quasi-satellites are successful a resonant orbit but are not gravitationally bound to Earth, allowing for much sustained, though unbound, proximity; portion mini-moons are characterized by impermanent gravitational captures by Earth, meaning they are gravitationally bound, albeit for a constricted time," the authors explicate successful their probe note.
Other existent quasi-satellites see 164207 Cardea (2004 GU9), 469219 Kamo'oalewa (2016 HO3), 277810 (2006 FV35), 2013 LX28, 2014 OL339, and 2023 FW13. 2025 PN7 is present the newest subordinate of that group.
This fig shows the known quasi-satellites wrong the dynamic discourse of the Arjuna asteroid belt: Cardea (gold point), Kamo'oalewa (red), 277810 (orange), 2013 LX28 (yellow), 2014 OL339 (violet), 2023 FW13 (pink), and 2025 PN7 (lime). The 2 reddish dashed vertical lines amusement the Hill radius, the portion astir Earth wherever Earth's gravity dominates implicit the Sun's gravitational influence. (Carlos de la Fuente Marcos and Raúl de la Fuente Marcos, Res. Notes AAS 2025)2025 PN7 is besides an Apollo asteroid, a larger radical of asteroids of which the Arjuna's are a tiny subclass. A captious favoritism betwixt them is that Arjunas don't person Earth-crossing orbits portion the Apollos do.
The researchers accidental that 2025 PN7 won't beryllium a quasi-satellite for precise long. "The disposable information bespeak that 2025 PN7 is simply a comparatively short-lived quasi-satellite of Earth," they write.
It'll lone beryllium a quasi-satellite for astir 128 years. Eventually, subtle changes successful orbital elements volition mean it leaves its resonance with Earth and volition similar travel a Trojan orbit or horseshoe orbit.
