Daphnis, the Wavemaker

January 24, 2017 11:52 PM

Tireless Cassini, now in its last cycle of death-defying orbits through Saturn's rings before its spectacular September 2017 Grand Finale, has captured an astonishing picture of tiny Daphnis making waves in Saturn's rings; Daphnis is one of the seven moons discovered by Cassini during its 20-year mission. Of course it already has a meme (with accompanying rhapsody).

Moons of Saturn discovered by Cassini:
2004:
Methone
Pallene (later found to have been snapped by Voyager 2 in 1981, but not definitively identified)
Polydeuces

2005: Daphnis (a shepherd moon, like the popular hamburger-shaped Pan); animated image of ring waves leading to Daphnis's discovery

2007: Anthe

2008: Aegaeon

2009: S/2009 S 1, a (provisional) propeller moonlet

2014: "Peggy," a possible A-ring moon in the process of forming

Saturn, which had 18 known moons when Cassini lifted off in 1997, now has 53 confirmed moons and 9 provisional moons.
Cassini has taken thousands of images of Saturn, its rings, and moons (including such popular favorites as Enceladus, Titan, Mimas, and Tethys), as well as other solar system bodies it passed on its journey. Here are some more of Cassini's greatest photographic hits.

Previously, Oceans under Ice on Enceladus; Huygens Phone Home; Landing with Huygens; Hexagonal Hurricane; Cassini in 2014; pluuuuuuuumes!

posted by Eyebrows McGee (14 comments total)

PS, at its closest to Earth, Saturn is 1.2 billion kilometers away. Daphnis is 8 km wide. (If Galileo weren't already dead he'd probably drop dead with delight at what the combination of rockets + optics + radio transmission of data can do for spotting moons.)
posted by Eyebrows McGee at 11:59 PM on January 24, 2017 [4 favorites]

Very cool. I am so small and far away.
posted by esto-again at 12:36 AM on January 25, 2017 [2 favorites]

Finally I have the perfect location to construct my secret lair. Mwahahahaha...
posted by zardoz at 2:57 AM on January 25, 2017 [3 favorites]

Don't tell me I'm the only one who read "2004: Methadone" ...
posted by oheso at 4:18 AM on January 25, 2017

Now I just need someone to start enumerating Saturn's rings so I can jump in with "...and Peggy!".
posted by a snickering nuthatch at 6:30 AM on January 25, 2017

Let's just hope the new regime keeps their hands off NASA long enough to actually see the mission to completion.
posted by Thorzdad at 6:36 AM on January 25, 2017 [1 favorite]

A meme, you say?

My name is Daphnis
I'm shepperd moon
But heres no sheeps
For me to spoon

So inn the skye
I do to things:
I mak the waves.
I lik the rings.
posted by moonmilk at 8:10 AM on January 25, 2017 [14 favorites]

I really love NASA's robots and their programmers.
posted by ridgerunner at 8:33 AM on January 25, 2017 [1 favorite]

Saturn's moon Pandora

"You are not in Kansas anymore. You are on Pandora, ladies and gentlemen. Respect that fact every second of every day. If there is a Hell, you might wanna go there for some R & R after a tour on Pandora. Out there beyond that fence every living thing that crawls, flies, or squats in the mud wants to kill you and eat your eyes for jujubes."
posted by Halloween Jack at 10:20 AM on January 25, 2017

I was always a Velma guy, might have to rethink that.
posted by Sphinx at 12:00 PM on January 25, 2017

Does the moon make the gap? Is she keeping it open?
posted by Oyéah at 1:55 PM on January 25, 2017

Yes, Daphnis keeps the gap open. Its gravity pushes the inner edge in and the outer edge out.
posted by BrashTech at 4:08 PM on January 25, 2017 [2 favorites]

How do you mean, pushes?

I'm guessing that Daphnis moves more slowly (radially) than the inner ring, so its gravity acts as a drag on the outermost elements of the inner ring which makes them fall back in. And it moves more quickly (again, radially) than the innermost elements of the outer ring, so it pulls them forward, and this acceleration makes them move further out. Is this right?
posted by Joe in Australia at 8:54 PM on January 25, 2017

Excellent, something worth dreaming about. Tiny shepherd moon surfing the ring waves.
posted by cnidaria at 10:17 PM on January 25, 2017 [2 favorites]