ZOOZVE

January 27, 2024 3:45 AM

It’s not a moon, but it’s also not not a moon. A strange label on his child’s bedroom poster leads Latif Nasser on an exploration of the solar system. Via Thread Reader and Radiolab.
posted by chrisulonic (16 comments total)

Contrary to the posters, we don’t live in a big clockwork, we live in a dance club, and while some of us are doing the same old waltz with our same old moon, there are bodies out there do-si-do-ing their way all over the solar system.

lovely.
posted by chavenet at 4:48 AM on January 27 [3 favorites]

I love the illustrator-misreading-their-own-handwriting-and-naming-the-thing-zoozve part. Twas ever thus.
posted by Thorzdad at 5:04 AM on January 27 [5 favorites]

Well damn, first I learn about imping from MeFi, and now quasi-moons. What a wonderful place this is!
posted by TedW at 6:34 AM on January 27 [2 favorites]

Recall also that our moon (Luna) is slowly moving away from the Earth. Given enough time, it would switch its orbit to the sun, however, the sun is expected to expand into a red giant before that, making the point rather moot.
posted by CheeseDigestsAll at 7:36 AM on January 27 [1 favorite]

This is great, thanks for sharing. I hope he gets the name change.
posted by sauril at 7:39 AM on January 27

The second I saw it, I figured it was "2002" rather than ZOOZ because a bunch of objects are just named after the year they were found. But it was still a neat story :)
posted by Foosnark at 1:56 PM on January 27 [2 favorites]

i thought this was going to be about CRUITHNE.
posted by graywyvern at 5:35 PM on January 27 [2 favorites]

I wanted to make a post on quasi-satellites of Earth when JWST launched, but never did; somewhere I have a few notes on the topic. Wikipedia has some good animations of QS orbits.
posted by neuron at 9:46 PM on January 27

Earth's moon would not escape to orbit the sun, even if it had enough time. The orbital decay of Earth's moon is due to angular momentum exchange between rotational motion and orbital motion: it's because of the difference between the day and the month. If given enough time, the Earth-Moon system would become mutually tidally locked, so that the same side of Earth always faced the Moon, the way that the Moon is already tidally locked to the Earth. This locking would happen at a distance of only about 1.5 times the current Earth-Moon distance, with a period of about 40×24 hours. That's well within Earth's "Hill sphere"; the Earth-Moon system is bound.

By contrast, Mars's outer moon could completely escape without its tides substantially changing the length of the Martian day, as could nearly all of the moon's of the gas giant planets. Mars's inner moon, on the other hand, already orbits faster than the Martian day, rising in Mars's western sky and setting in its east. The way for the inner moon to have its orbit synchronized with Mars's rotation is for the moon to spiral inward, eventually breaking into little pieces and landing on the Martian surface.

The moons of the gas giants are all way too small to tidally lock their planets. Pluto and Charon are mutually locked already, but the other bodies in that system have chaotic orbits. I know there is at least one asteroid with a moon (Ida and Dactyl, I think), but I don't know whether they're locked yet or not.
posted by fantabulous timewaster at 6:26 AM on January 28 [4 favorites]

I am annoyed that Nasser says this object associated with Venus is the first quasi-moon ever discovered, ever, in the whole universe, and then compares it to the Trojan asteroids, which (by this definition) are all quasi-moons of Jupiter.
posted by fantabulous timewaster at 6:31 AM on January 28 [1 favorite]

The article is very cute. The weird choppy presentation is pretty off putting though. I am assuming the audio version is also off putting because Radiolab.
posted by The Manwich Horror at 8:14 AM on January 28 [2 favorites]

It was announced today that (524522) Zoozve is now the official name of 2002 VE₆₈. It's been published in the WGSBN Bulletin put out today along with the other planetoids that received official names recently. It's on Page 9 of the PDF version here with a specific note about the story behind it.

Surprisingly fast work -- some planetoids, even fairly significant ones, don't get names for decades.
posted by Quindar Beep at 12:25 PM on February 5 [2 favorites]

As a celestial body, Zoozve ought to have a dord.
posted by Cardinal Fang at 5:35 AM on February 6 [3 favorites]

I was mistaken a few comments up when I wrote that the Trojan asteroids are quasi-moons of Jupiter. In the usual rotating-coordinate-system map of the Lagrange points,

                             L4


                                  ^
                                    ^ (orbit goes this way)
                                     ^
L3               sun              L1 . L2





                             L5

the Trojan orbits are mostly stable in the vicinities of L4 and L5. There is a so-called "horseshoe orbit" where a leading Trojan near L4 can get perturbed an end up as a trailing Trojan near L5, or vice versa. But it's called a horseshoe orbit because the small body goes the long way, via the L3 on the far side of the Sun.

Zoozve is apparently doing a different and genuinely novel thing: going back and forth between L4 and L5, but doing so on the planet side, making kind of an egg shape that encloses L1 and L2.

I didn't think that was actually possible, given the energy landscape of the orbit. But "impossible" is a different creature from "only marginally stable." Apparently Zoozve is only going to quasi-orbit Venus a few thousand times before it gets chaotically ejected elsewhere in the solar system. It's kind of petty for me, a person who won't orbit the sun a hundred more times, to complain about Zoozve being too temporary to refer to as a "moon."

Score one for the radio journalist against the overconfident internet nerd. Whoops.
posted by fantabulous timewaster at 8:32 AM on February 6 [2 favorites]

It turns out, if you were to just look at the moon's orbit without being aware of the nearby earth, you would probably think the moon was simply orbiting the sun. At a glance the orbit just looks like a big circle around the sun - not the sort of spirograph-like-curlycue most of us imagine it would be.

Interesting discussion here - including criteria for deciding whether it "really" orbits the earth or the sun.

(And of course the "real" answer to that question is, it definitely orbits both the earth and the sun.)
posted by flug at 5:24 AM on February 7 [1 favorite]

Note that your own path around the sun isn't a spiral/curlicue either. Earth's rotation carries you to the east at 500 m/s ≈ 1100 mph, or slightly slower if you're not at the equator. At noon, when Earth's orbital motion is carrying you mostly to the west, it's doing so at 30 000 m/s. If you wanted to make your path around the Sun into a curlicue, you'd have to travel east at midday at nearly three times Earth's escape velocity.

Jupiter's moons Io and Europa have curlicue paths around the Sun, but Ganymede and Callisto don't. The only planet where a surface dweller (or a one-atmosphere dweller for the gas giants) has a curlicue path is Saturn, whose ring particles and inner moons likewise make curlicues, but whose outer large moons (Rhea, Titan, Iapetus) don't. [I only checked for paths that actually reverse direction, like in an ℓ. The Moon's orbit around the Sun is convex everywhere, but I'm not sure how to check for that.]
posted by fantabulous timewaster at 9:07 AM on February 7