a million moons

comrade alph posted this on the thread devoted to twitter but moons deserve their own thread!

Last January, I noticed something peculiar in my 2yo’s bedroom that - after a year of obsessive reporting - led me to a profound cosmic revelation about what’s even possible in our universe. A 🧵. pic.twitter.com/pHFStIdawh

— Latif Nasser (@latifnasser) January 26, 2024

twitter-thread is abt venus's not-not moon zoozve and the thread is abt all the moons and not-not-moons (like trojans and such) in the solar system and elsewhere

quasi-moons! that is a great thread

what's it about

for example these: a trojan is “a small celestial body (mostly asteroids) that shares the orbit of a larger body, remaining in a stable orbit approximately 60° ahead of or behind the main body near one of its Lagrangian points…. trojans can share the orbits of planets or of large moons"

but also whatever zoozve is (acc. the twitter thread a “quasi-moon”, viz the first body in the solar system discovered to be orbiting two bodies at once)

the bulk of the twitter thread is a little multi-tweet journey of chatty discovery: latif nasser saw the name on his kid's wallposter, wanted to know more but found nothing, asked various astronomers and the poste'rs illustrator, and after initial puzzlement it was identified: https://en.wikipedia.org/wiki/(524522)_2002_VE68

(the illustrator had i turns out misread his own scribbled notes and zoozve (good name) was actually 2002-VE (boring name); the actual discovere has fond so many small bodies in the solar system thae he had entirely forgotten about this one)

funny wikipedia diagram of zoozve's orbit:
https://upload.wikimedia.org/wikipedia/commons/f/fd/Animation_of_2002_VE68%27s_orbit_-_rotating_frame.gif

also funny: this table from the wikipedia article on nos. of trojans per planet (simplified so as not to have to post a real table on ilx)

Mercury: 0
Venus: 1
Earth: 2
Mars: 1
Jupiter: 11552
Saturn: 0
Uranus: 2
Neptune: 28

that's too many trojans jupiter

Saturn is getting fucked over there, its ring has some mini-moons embedded in them.

britannica way ahead of u calz:
"Although Saturn’s rings and moons may seem to constitute two groups of quite different entities, they form a single complex system of objects whose structures, dynamics, and evolution are intimately linked. The orbits of the innermost known moons fall within or between the outermost rings, and new moons continue to be found embedded in the ring structure. Indeed, the ring system itself can be considered to consist of myriad tiny moons—ranging from mere dust specks to car- and house-sized pieces—in their own individual orbits around Saturn. Because of the difficulty in distinguishing between the largest ring particles and the smallest moons, determining a precise number of moons for Saturn may not be possible."

"myriad tiny moons" is the secret true name of this thread

anything as big as Saturn will have plenty of myriads!

Britannica close to sneaking in a 'single atom' theory of the universe there, eg:

"Although the Universe may seem to constitute groups of quite different entities, it forms a single complex system of objects whose structures, dynamics, and evolution are intimately linked...determining a precise number/description of individual entities may not be possible."

You have to try, recognising the inherent difficulties ...Don't just give up!

Love the image of the writer of that entry steadily coming adrift as the true situation dawns on them.

Single Bullet Atom Theory=Big Bang.
So I was wondering, if Pluto is no longer a planet, is Charon still a moon?
wiki sez:

The dwarf planet* Pluto has five natural satellites.[1] In order of distance from Pluto, they are Charon, Styx, Nix, Kerberos, and Hydra.[2] Charon, the largest, is mutually tidally locked with Pluto, and is massive enough that Pluto–Charon is sometimes considered a double dwarf planet.[3]...the system's barycenter lies between them, approximately 960 km above Pluto's surface.[6][a] Charon and Pluto are also tidally locked, so that they always present the same face toward each other....The reddish-brown cap of the north pole of Charon is composed of tholins, organic macromolecules that may be essential ingredients of life. These tholins were produced from methane, nitrogen, and related gases which may have been released by cryovolcanic eruptions on the moon,[19][20] or may have been transferred over 19,000 km (12,000 mi) from the atmosphere of Pluto to the orbiting moon.[21]

So, the three criteria of the IAU for a full-sized planet are:

It is in orbit around the Sun.
It has sufficient mass to assume hydrostatic equilibrium (a nearly round shape).
It has “cleared the neighborhood” around its orbit.
Pluto meets only two of these criteria, losing out on the third. In all the billions of years it has lived there, it has not managed to clear its neighborhood. You may wonder what that means, “not clearing its neighboring region of other objects?” Sounds like a minesweeper in space! This means that the planet has become gravitationally dominant — there are no other bodies of comparable size other than its own satellites or those otherwise under its gravitational influence, in its vicinity in space.

So any large body that does not meet these criteria is now classed as a “dwarf planet,” and that includes Pluto, which shares its orbital neighborhood with Kuiper belt objects such as the plutinos.[/q\]
That's from https://www.loc.gov/everyday-mysteries/astronomy/item/why-is-pluto-no-longer-a-planet/

Charon info from https://en.wikipedia.org/wiki/Charon_(moon)
and https://en.wikipedia.org/wiki/Moons_of_Pluto

thread delivers

I think there can be a moon of something that isn't a planet - e.g. asteroids Ida and Dactyl, and I think some of the large KBOs like Eris (?) have moons too.

Correct.

A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are colloquially referred to as moons, a derivation from the Moon of Earth.

Seven objects commonly considered dwarf planets by astronomers are also known to have natural satellites: Orcus, Pluto, Haumea, Quaoar, Makemake, Gonggong, and Eris.[1] As of November 2021, there are 442 other minor planets known to have natural satellites.[2]

https://upload.wikimedia.org/wikipedia/commons/f/f3/InnerSolarSystem-en.png

Trojans, Hildas and Greeks. Jupiter is very promiscuous.

xp that minor planet satellite figure is insane! Feel like my solar system knowledge tops out in about 1986.

poor space junk, never getting to be an actual orbiting body

Makemake and Gonggong were my two favourite Teletubbies

Feel like my solar system knowledge tops out in about 1986.

Same! Was quite pleased with my primary school self, knowing all 13 Jovian moons, was able to adjust to the handful of Voyager-era additions, but it just accelerated out of control in the last 20 years. If Jupiter's moons were a broken glass on the floor, Galileo picked up the big shards for the recycling, C19-20th was dustpan and brush, and everything since has been dealt with a hoover. If you were to walk through Jupiter's kitchen, you wouldn't feel most of these underfoot is what I think I'm saying.

Speaking of Voyager, I love these reprocessed images, the detail is incredible to me:
https://www.planetary.org/articles/voyager-wide-angles-jupiter
https://planetary.s3.amazonaws.com/web/assets/pictures/VGER-40-JUPITER-BLOG__Figure_C.jpg
https://planetary.s3.amazonaws.com/web/assets/pictures/VGER-40-JUPITER-BLOG__Figure_O.jpg

calling them greeks vs trojans (ahead vs behind jupiter in its orbit, or leading and following) (viz it goes counterclockwise in that diagram) makes sense i guess

calling them hildas? they are all named after asteroid HILDA (which is one of them) and hilda is named for one of the daughters of austrian astronomer theodor von oppolzer (1841-86)

thanks to him there's also an asteroid agatha (another daughter) and an asteroid coelestina (his wife)

Galileo didn't know yet that in 15 year cycles earthbound eyes see Saturn's relatively wafer thin ring head on so effectively it disappears to the naked eye, he posted the early 17th c equivalent of wtf! in his dairy.

"I do not know what to say in a case so surprising, so unlooked for and so novel"

what he thought he saw (ambushed by unexpected rings of saturn):
https://pbs.twimg.com/media/E-3LipVWQAUytMn?format=jpg
who he actually saw (better boop's unnamed monkey)
https://static.wikia.nocookie.net/bettyboop/images/7/72/Betty-monkey-1-.jpg

better boop

it must have been a hell of trip being the first people to look at the planets with a telescope, and then eventually cursing at how limited and crappy the first telescopes were for this purpose.

The "anagrams" those early astronomers used to record but obscure their unpublished discoveries!

Huygens on establishing that Saturn had rings: "aaaaaaa­ccccc­deeeeeg­hiiiiiii­llllmm­nnnnnnnnn­oooopp­qrrs­tttttuuuuu".
Great at grinding glass, hopeless at Scrabble.

I used to think of the asteroid belt as being something that is huge, then I heard on some program that it contains 4% of the mass of our moon. Ceres is pretty big, but seemingly it's mostly just smallish chunks of primordial rubble that never managed to come to anything.

most of them don't even get to be round! you see a photo of this or that mini-moon or asteroid and it's like the grainy ghost of 1 x potato

I was reading about the asteroid belt recently, when someone was complaining you never see photos of it. The average distance between asteroids is 965,600 km, so if you took a wide-angled-enough photo to contain two of them, they'd be waaaaaaaaaaaay too small to see.

everything I know about asteroids comes from The Little Prince

https://s26162.pcdn.co/wp-content/uploads/2018/04/The-Little-Prince-1.jpg

When we first moved to the UK in 2016 my older son (then aged 5/6) got really into space stuff and would spend ages watching this channel of planet/star/moon "songs" which all have the same bizarre lack of a tune

https://www.youtube.com/watch?v=4tw_RiQp6H8

omg, we are approaching the asteroid belt at breakneck speed - this is a suicide mission (based on my knowledge gleaned from 1970's children's library books)

ship's computer: it'll be reet, there's practically fuck all there m8

SPACE 1979

Cool compendium of moon-mining films.. I've seen a few of these but not all

https://vissiniti.com/astro-mining-in-the-movies/

am reading "The Menace From Earth" by Robert Heinlen rn w my 12-yo and forgot how great it is. On The Moon, instead of skiing or surfing, you go flying in custom wings why because at 1/6 your Earth weight the physics work out (artificial air has been a feature of The Moon for several generations). Plenty of hijinks with beginners from Earth wearing bright orange painted wings for safety and snagging the narrator's love interest

everything i know about moons i learned from james thurber's many moons

https://thumbs.worthpoint.com/zoom/images1/1/0415/24/james-thurber-many-moons-philip-reed_1_527f371e8acf072f02064f9c3bcb1a1e.jpg

https://i.imgur.com/Qlob47U.png

slightly off-topic but I was watching a video about Jumbos earlier (Jupiter-mass binary objects) earlier. JWT has found about 40 of these things in the Orion Nebula - many of them in pairs, they are very young free-floating Jupiter type planets (although some might say they aren't technically planets) that possibly might have broke free of the gravity of failed stars that weren't big enough to do nuclear fusion and are burning out. or something like that - fascinating stuff.

New pix x names!

Japan’s ‘Moon Sniper’ wakes up and shares new images of lunar surface

...The spacecraft landed facing the wrong direction after one of its engines failed during landing, meaning its solar cells couldn’t generate electricity and it had to rely on limited battery power, according to the Japan Aerospace Exploration Agency (JAXA).

The agency shut off the lunar explorer to conserve its battery, saying it would automatically be restarted if its solar panel began generating power as the angle of the sun changed.

On Monday, JAXA announced on the social media platform X that it had “succeeded in establishing communication with (Smart Lander for Investigating Moon, or SLIM) last night and have resumed operations!”

The explorer has also captured new images of the lunar surface and returned them to the mission team on Earth.

The lander is equipped with a multi-band camera to capture images of the lunar surface. The mission team previously combined 257 images captured by SLIM right after landing to create a mosaic showcasing the landing site. Team members also nicknamed rocks of interest, choosing monikers that correspond to their size estimates.

A new image shared by the agency on Monday is a closeup of the rock “Toy Poodle.” The lander is designed to briefly study rocks that could reveal insights into the moon’s origins.

Ah, calzino, those JUMBOs are cool, thanks for that.

poor jumbos, locked in a dance of entropy and heat loss

I love the idea of a small moon orbiting two bodies at once, in a complex parabolic track

"Zoozve orbits one thing: the sun. It spends all day every day doing that. BUT Venus also has a teeny gravitational toehold on it such that it ALSO ORBITS VENUS AT THE SAME TIME."

SLiM Tha Moon Sniper : Lunar Beats Vol 2 : Darkside of the BOOM

Mimas' surprise: Tiny moon holds young ocean beneath icy shell
https://phys.org/news/2024-02-mimas-tiny-moon-young-ocean.html

Hidden beneath the heavily cratered surface of Mimas, one of Saturn's smallest moons lies a secret: a global ocean of liquid water. This astonishing discovery, led by Dr. Valéry Lainey of the Observatoire de Paris-PSL and published in the journal Nature, reveals a "young" ocean formed just 5 to 15 million years ago, making Mimas a prime target for studying the origins of life in our solar system.

"Mimas is a small moon, only about 400 kilometers in diameter, and its heavily cratered surface gave no hint of the hidden ocean beneath," says Dr. Nick Cooper, a co-author of the study and Honorary Research Fellow in the Astronomy Unit of the School of Physical and Chemical Sciences at Queen Mary University of London.

"This discovery adds Mimas to an exclusive club of moons with internal oceans, including Enceladus and Europa, but with a unique difference: its ocean is remarkably young, estimated to be only 5 to 15 million years old."

thread delivers, again

young internal ocean is my soundcloud rap name

https://earthsky.org/upl/2024/02/Uranus-moon-S2023U1-Magellan-November-4-2023.jpg

New moons of Uranus and Neptune announced
https://carnegiescience.edu/new-moons-uranus-and-neptune-announced

Washington, D.C.— The Solar System has some new lunar members—the first new moon of Uranus discovered in more than 20 years, and likely the smallest, as well as two new moons of Neptune, one of which is the faintest moon ever discovered by ground-based telescopes. The discoveries were announced today by the International Astronomical Union's Minor Planet Center.

“The three newly discovered moons are the faintest ever found around these two ice giant planets using ground-based telescopes,” explained Carnegie Science’s Scott S. Sheppard. “It took special image processing to reveal such faint objects.”

The new Uranian member brings the ice giant planet’s total moon count to 28. At only 8 kilometers, it is probably the smallest of Uranus’ moons. It takes 680 days to orbit the planet. Provisionally named S/2023 U1, the new moon will eventually be named after a character from a Shakespeare play, in keeping with the naming conventions for outer Uranian satellites.

...

The brighter Neptune moon now has a provisional designation S/2002 N5, is about 23 kilometers in size, and takes almost 9 years to orbit the ice giant. The fainter Neptune moon has a provisional designation S/2021 N1 and is about 14 kilometers with an orbit of almost 27 years. They will both receive permanent names based on the 50 Nereid sea goddesses in Greek mythology.

there's always an eclipse somwhere ffs

time to update the speadsheet again

https://www.forbes.com/sites/ariannajohnson/2024/09/19/temporary-mini-moon-will-begin-orbit-around-earth-next-week-what-to-know/

lol at "what to know", yr not the boss of me forbes magazine, i know what i choose (very little)

PAN HAZ CHEEZBURGER

https://assets.science.nasa.gov/dynamicimage/assets/science/psd/solar/2023/07/PIA21436_modest.jpg

"… the innermost named moon of Saturn.[4] It is approximately 35 kilometres across and 23 km wide and orbits within the Encke Gap in Saturn’s A Ring. Pan is a ring shepherd and is responsible for keeping the Encke Gap free of ring particles. It is sometimes described as having the appearance of a walnut or ravioli.[5]" (or else what it is, which is a cheeseburger)

this fellow was on TV on monday night, the handsome pop-star physicist was explaining how gravity did the ring (not particularly well in my opinion)

the pop star physicist (not the rock star physicist) was recently also on about this, and i enjoyed the name:

https://arxiv.org/abs/1004.1091
"The Potato Radius: a Lower Minimum Size for Dwarf Planets"