Quasi-moon
The post begins with the excerpt about the quasi-moon, followed by looking up related articles on SOTT, and what characterises the classes of objects that have been observed to become quasi-moons in terms of their orbits. The Earth is not alone in picking up strays, even fairly small asteroids, below a diameter of 1km can appear with a companion. Along the way, it turned out that 1996, the year mentioned in the recent session, was also the year of the visible comet Hyakutake.
Earth's 8th official quasi-moon... How long has it been in Earth's orbit? - Since 1996.
Session 27 September 2025
Q: (Gaby) Earth's 8th official quasi-moon...
(L) "Quasi-moon", I love that word, it's so quasi! [Laughter]
(Gaby) ...was discovered earlier this year, which is slightly smaller than the meteor that exploded over Chelyabinsk, Russia, in 2013. How long has it been in Earth's orbit?
A: Since 1996.
For gravitational interaction to occur, that would make an object become associated with the Earth as a quasi-moon, the speeds and orbits of the smaller object and the Earth would have to be compatible.
Articles on SOTT related to the topic of quasi-moons
Meet 2025 PN7, Earth's newfound quasi-moon
Earlier images of the object extend back to 2014. It now appears to have been on a quasi-moon orbit for about 60 years, and it will remain so for about 60 more. Eventually, though, it will revert to a horseshoe orbit, one that brings it periodically close to Earth only to back away again, never completing a full circle around our planet.
Images go back to 2014. How do they speculate about the other 50 years? Probably from analyzing the orbit, with the added assumption that all went according to plan, from now until back then, but are orbits of such objects always accurately retraceable?
The next two are about the same object,
2024 PT5 :
Earth's 'mini moon' asteroid escapes after 2 months in orbit Nov 2024
Where the rock came from is something of a mystery, but scientists have good reason to believe it is
actually a chunk of the moon itself, likely
ejected by an asteroid impact centuries ago.
Two articles, and two suggestions about the origin:
'2nd Moon' orbits Earth after getting stuck in planet's gravity—here's where it came from Oct 2024
Where Did It Come From?
Over the years, countless other space objects like 2024 PT5 have grazed by Earth. This NEO is said to originate from the Arjunas, a secondary asteroid belt in the solar system that aligns closely with Earth. Hoards of NEOs can be found within this cluster, and some have even visited Earth before. The latest flyby closely resembles a prior one called 2022 NX1, which orbited Earth in 1981 and 2022 before bidding farewell. When 2024 PT5 says sayonara in November, it won't return to greet us again until 2055.
A comment about the Arjuna asteroids:
The Arjuna asteroids (also known as "Arjunas") are a dynamical group of asteroids in the Solar System. Arjunas are near-Earth objects (NEOs) whose orbits are very Earth-like in character, having low inclination, orbital periods close to one year, and low eccentricity.
Potential members of the
Arjuna group with their Apollo (APO) or Aten (ATE) group classification in parentheses, include:
The
Apollo asteroid Wiki has an image that shows what the differences in orbit are between Apollo and Atens:
The Apollo asteroids cross the orbit of the Earth because when they are at their nearest distance from the Sun, their perihelion, they are closer than when the Earth is the furthest away from the Sun, its aphelion.
For the Aten class asteroids, the situation is the reverse, they cross the orbit with the Earth, because when they are the furthest away from the Sun at their aphelion, they are further away, than when the Earth is at its closest distance from the Sun, its perihelion.
The Chelyabinsk meteor, that exploded over the city of Chelyabinsk in the southern Urals region of Russia on February 15, 2013, injuring an estimated 1,500 people with flying glass from broken windows, was an Apollo-class asteroid.
The Wiki says that more than 21,000 Apollo class objects are known, of these about 10 % are potential hazards.
Another SOTT article:
New 'quasi-moon' asteroid 2023 FW13 discovered near Earth, has been travelling alongside our planet since 100 BC June 2023
Following 2023 FW13's initial discovery in March,
space observers dug into the data and found observations of the asteroid dating all the way back to 2012, according to Live Science's sister site
Space.com.
"all the way back to 2012" (how old is that writer), and then backdated to the time Caesar was born, is along the lines of the story about 60 years for the 2025 PN7 which they can reliably trace to 2014. There is of course a difference between 2000 years and 60; maybe they match observations to models and then they rewind the models to show what the models tells them reality looked like back in time.
A comparatively small object can have a moon:
NASA spacecraft discovers asteroid sporting tiny moon Nov 2023
In data and images beamed back to Earth, the spacecraft confirmed that Dinkinesh is barely a half-mile (790 meters) across. Its closely circling moon is a mere one-tenth-of-a-mile (220 meters) in size.
If a comet has a diameter of a few km, many times the size of the above case, would anything prevent it from having companions?
Are there more quasi-moons out there? Given that the objects can be quite small, and difficult to observe, there are probably more, and in a way the articles admit as much. "Oh, it has been out there for 60 years! Oh, it has been out there since Caesar was born!" At the same time, the gravity field of the Earth is not like Saturn og Jupiter, and the ability to attract an object is not nearly the same. Perhaps there is also something about the nearness to the Sun, as neither Mercury nor Venus have moons of their own. Our Moon also does not have moons, but it has scars from impacts. To continue on that tought, if one compares the list of large fireballs and impacts that have hit Earth with the short list of small orbiting or semi-orbiting objects, it is clear what is more common for Earth.
1996 - the year of Comet Hyakutake
The Cs mentioned the 1996 in the session as the time for the beginning of the association with the gravity field of the Earth. Wondering if there per chance were any comets that passed by in 1996. There was
Comet Hyakutake, but it would be too fast to enter into orbit around the earth. Nevertheless it was still an interesting event that illustrated how quickly a comet can show up in the skies.
Comet Hyakutake (formally designated C/1996 B2) is a comet discovered on 31 January 1996.[1] It was dubbed the Great Comet of 1996; its passage to within 0.1 AU (15 Gm) of the Earth on 25 March was one of the closest cometary approaches of the previous 200 years. Reaching an apparent visual magnitude of zero and spanning nearly 80°, Hyakutake appeared very bright in the night sky and was widely seen around the world. The comet temporarily upstaged the much anticipated Comet Hale–Bopp, which was approaching the inner Solar System at the time.
Hyakutake is a long-period comet that passed perihelion on 1 May 1996. Before its most recent passage through the Solar System, its orbital period was about 17,000 years,[2][7] but the gravitational perturbation of the giant planets has increased this period to 70,000 years.[2][7]
Aphelion ~1,320 AU (inbound)[a] ~3,500 AU (outbound)
If gravitational perturbations of the the giant planets could change the orbital period of Hyakutake from 17,000 to 70,000 years, what might a dark companion of the Sun, with a mass about 35 times heavier compared to Jupiter be able to do?
Hyakutake moved from being invisible to being prominent within weeks
Hyakutake became visible to the naked eye in early March 1996. By mid-March, the comet was still fairly unremarkable, shining at 4th magnitude with a tail about 5 degrees long. As it neared its closest approach to Earth, it rapidly became brighter, and its tail grew in length. By March 24, the comet was one of the brightest objects in the night sky, and its tail stretched 35 degrees. The comet had a notably bluish-green colour.[7]
Comet Hyakutake's trajectory through the inner solar system, with a high inclination, passed closest to the Earth in late March 1996, passing over Earth's north pole. It was at perihelion on May 1.
It is fascinating, (since this case was not terrifying) that a quiet sky can light up with such a short time.
The Wiki explains how a satellite managed to register localized changes in space following the passage of comet Hyakutake. The example can give us some idea of what a passage of a comet can mean electrically and magnetically in some instances.
The Ulysses spacecraft made an unexpected pass through the tail of the comet on 1 May 1996.[21] Evidence of the encounter was not noticed until 1998. Astronomers analysing old data found that Ulysses' instruments had detected a large drop in the number of protons passing, as well as a change in the direction and strength of the local magnetic field. This implied that the spacecraft had crossed the 'wake' of an object, most likely a comet; the object responsible was not immediately identified.[22]
From the passage of Comet Hyakutake, more is known about what can happen, when a comet passes near. One question might be, when there was a drop in protons, was that because they were absorbed or neutralized by negative charges or where did thy go? Looking around for ideas, there was from an
electric universe newsfeed:
A predictive milestone for the electric comet model. In her November 2021 doctoral thesis, Sofia Bergman, PhD student at the Swedish Institute of Space Physics, used SPIS (Spacecraft Plasma Interaction Software) to measure low-energy ions around Comet 67P/Churyumov-Gerasimenko. A large amount of positive ions were measured flowing inward towards the comet's nucleus—instead of outward as expected—evidence of a negatively charged object.