Astronomers Discover Previously Unknown Quasi-Moon Near Earth (cnn.com) 35
"Astronomers have spotted a quasi-moon near Earth," reports CNN, "and the small space rock has likely been hanging out near our planet unseen by telescopes for about 60 years, according to new research."
The newly discovered celestial object, named 2025 PN7, is a type of near-Earth asteroid that orbits the sun but sticks close to our planet. Like our world, 2025 PN7 takes one year to complete an orbit around the sun...
The newly found 2025 PN7 is just one of a handful of known quasi-moons with orbits near our planet, including Kamo'oalewa, which is also thought to be an ancient lunar fragment. Kamo'oalewa is one of the destinations of China's Tianwen-2 mission launched in May, which aims to collect and return samples from the space rock in 2027. The Pan-STARRS observatory located on the Haleakala volcano in Hawaii captured observations of 2025 PN7 on August 29. Archival data revealed that the object has been in an Earth-like orbit for decades.
The quasi-moon managed to escape the notice of astronomers for so long because it is small and faint, said Carlos de la Fuente Marcos, a researcher on the faculty of mathematical sciences at the Complutense University of Madrid who recently authored a paper about the space rock. The paper was published on September 2 in the journal Research Notes of the American Astronomical Society, which is for timely non-peer-reviewed astronomical observations. The space rock swings within 186,000 miles (299,337 kilometers) of us during its closest pass of our planet, de la Fuente Marcos said.... "It can only be detected by currently available telescopes when it gets close to our planet as it did this summer," de la Fuente Marcos explained. "Its visibility windows are few and far between. It is a challenging object...."
Astronomers are still trying to figure out 2025 PN7's size. About 98 feet (30 meters) across is a reasonable estimate, de la Fuente Marcos said. It also has the potential to be 62 feet (19 meters) in diameter, according to EarthSky. The space rock is currently the smallest-known quasi-moon to have orbited near Earth, de la Fuente Marcos said.
The newly found 2025 PN7 is just one of a handful of known quasi-moons with orbits near our planet, including Kamo'oalewa, which is also thought to be an ancient lunar fragment. Kamo'oalewa is one of the destinations of China's Tianwen-2 mission launched in May, which aims to collect and return samples from the space rock in 2027. The Pan-STARRS observatory located on the Haleakala volcano in Hawaii captured observations of 2025 PN7 on August 29. Archival data revealed that the object has been in an Earth-like orbit for decades.
The quasi-moon managed to escape the notice of astronomers for so long because it is small and faint, said Carlos de la Fuente Marcos, a researcher on the faculty of mathematical sciences at the Complutense University of Madrid who recently authored a paper about the space rock. The paper was published on September 2 in the journal Research Notes of the American Astronomical Society, which is for timely non-peer-reviewed astronomical observations. The space rock swings within 186,000 miles (299,337 kilometers) of us during its closest pass of our planet, de la Fuente Marcos said.... "It can only be detected by currently available telescopes when it gets close to our planet as it did this summer," de la Fuente Marcos explained. "Its visibility windows are few and far between. It is a challenging object...."
Astronomers are still trying to figure out 2025 PN7's size. About 98 feet (30 meters) across is a reasonable estimate, de la Fuente Marcos said. It also has the potential to be 62 feet (19 meters) in diameter, according to EarthSky. The space rock is currently the smallest-known quasi-moon to have orbited near Earth, de la Fuente Marcos said.
Too little (Score:3)
19 meters in diameter? Nah, not worth naming it
GatGPT5:
Short answer: a 19-meter asteroid is “Chelyabinsk-class.” It almost certainly explodes high in the atmosphere (an airburst) rather than making a crater. Think spectacular fireball, a very loud shock wave, lots of broken windows—and mostly local damage.
Re: Too little (Score:4, Funny)
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Not necessarily. The meteorite that caused the impact the 13 meter wide impact crater in Carancas, Peru, was only about 0.9 to 1.7 meters in diameter. It depends entirely on the internal composition of the rock and the angle of impact. Chelyabinsk entered the atmosphere at an oblique angle, creating a fire trail hundreds of kilometers long as it passed through the atmosphere and causing extreme internal stresses before it blew up. Carancas was nearly vertical and no one noticed anything until it hit and
Small enough to be interesting (Score:2)
Re: Small enough to be interesting (Score:3)
So 100 feet is quasi-moon, then promote Pluto (Score:3)
Promote Pluto back to a full planet.
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Given its small size it might be better to land a small mining module on the rock and then carve it up in situ to expand that module into a small space station.
We need to do this with the Taurus cluster to prevent another Tunguska event, but better to start small and practice closer. It's so much more profitable to not lift mass from Earth than it is to send it down.
Taurus has enough asteroids to build Space Station Alpha. Might be a nice vacation spot.
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You people! don't even want to return to the office and you are now talking about vacationing in a teenie tiny space-station with basically nothing to do but work? Right.../s
Obligatory (Score:4, Funny)
What's with the "moon" term? (Score:2)
It's just a small rock/asteroid in a fleeting orbit. Calling it a quasi-satellite would seem much more appropriate. I get the feeling someone wanted to sex up the story.
Re:What's with the "moon" term? (Score:4, Informative)
Per the actual discussion identifying the object, [groups.io] it is a quasi-satellite. I think the moon related naming comes from the general public thinking of satellites as being man-made objects in Earth's orbit. However, plenty of publications have referred to such objects as being quasi-moons, including writers for The Planetary Society.
https://www.planetary.org/arti... [planetary.org]
Quasi-moons
Earth’s quasi-moons get their name because, from a certain vantage point, they appear to act like moons. But from a wider perspective, it becomes obvious that they aren’t actually moons at all — they’re asteroids.
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If "general public thinking" is the metric... the naming seems unhelpful in that regard since, at least based on TFS, it's not orbiting the earth - it's orbiting the sun and just staying in earth's proximity.
I would think something like "near earth asteroid" would be a less confusing term for such objects.
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Looks like "near earth asteroid" is already in use:
https://en.wikipedia.org/wiki/... [wikipedia.org]
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I think most of the genenal public thought of Pluto as a planet, but that wasn't enough for Pluto.
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it's not orbiting the earth
It does orbit Earth on occasion before returning to orbit the Sun. TFS isn't very clear about that fact.
Random bright object in the sky? Probably ISS. (Score:4, Funny)
That's no moon. It's a space station. :-D
No type of moon (Score:2)
>" quasi-moon near Earth"
It isn't ANY type of "moon". A moon orbits a planet, regardless of what size, shape, or how erratic the orbit. This object orbits only the sun.
According to the paper:
"Meet Arjuna 2025 PN7, the Newest Quasi-satellite of Earth"
"Out of the Arjunas and NOT COUNTING those which can be temporarily captured as mini-moons of Earth, quasi-satellites are our closest companions. Here we show that 2025 PN7 is a quasi-satellite,[...] engaged in a 1:1 mean-motion resonance with our planet, b
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A moon orbits a planet,
Then the Moon isn't a moon either. It orbits the Sun, the Earth only causing a small wobble in its orbit.
Re: No type of moon (Score:2)
Re: No type of moon (Score:2)
Why deny the truth, it is out there.
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Only for a certain sexual orientation . . .
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The Moon also orbits the centre of the Milky Way, which might happen to host a supermassive black hole or some other spectacular massive object. The Moon orbits both a planet and some other objects, so it's a moon, by that definition.
I'm not sure if an object which orbits the Moon is still a moon, though.
Please stop... (Score:2)
The space rock swings within 186,000 miles (299,337 kilometers) of us during its closest pass of our planet, de la Fuente Marcos said
Note to CNN editors: You really should recognize that the figure of "186,000 miles" is approximate. Translating it to "299,337 kilometers" implies a degree of precision which in this case doesn't exist. Calling it "300,000 kilometers" would be much better.
It just occurred to me that the literality of the conversion may be an AI artifact, in which case we can expect a lot more of this crap.
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What if it's 299,792.458 km?
Do we send the SYN-ACK?
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What if it's 299,792.458 km?
Do we send the SYN-ACK?
Sorry, you've lost me. What's the connection between the distance that light travels in a millisecond, and TCP handshaking?
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Note to CNN editors: You really should recognize that the figure of "186,000 miles" is approximate. Translating it to "299,337 kilometers" implies a degree of precision which in this case doesn't exist. Calling it "300,000 kilometers" would be much better.
It just occurred to me that the literality of the conversion may be an AI artifact, in which case we can expect a lot more of this crap.
The same goes for the size. It's pretty clear that scientists were ballparking its size in metric units, and converting the fractional units with that much precision was stupid. Calling it "about a hundred feet or thirty meters" would have been a lot better.
And this sort of thing happened long before AI was in the picture. People don't understand significant digits, and it's worse when it comes to estimates.
As for distance away, it would have been better to include something like its closest approach put
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Everything's an AI artifact. It's not like lazy people who slept through high school chemistry have been punching unit conversions into calculators for generations.
One Light Second Away (Score:2)
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At its closest point, most of the time it's considerably further away. At least part of the time it's in a 'horseshoe orbit', a solar orbit affected by a larger body. It might start orbiting within the orbit of Earth, so is faster. It gradually catches up to Earth, the gravitation effect of Earth speeds it up into a wider, slower orbit. Now Earth gradually catches up to it, slows it down, and drops it into a lower, faster orbit. Wash, rinse, repeat. Earth has several asteroids that it creates horsesho