Saturn's New Moons Named

sebFlyte writes "The BBC is reporting that three new moons found orbiting Saturn at the end of last year have been named. 'Two moons detected in August have been given the names Methone and Pallene, while another found in October has been provisionally named Polydeuces.' Polydeuces is also reported as being a very strange object-- a trojan moon. It sits in a spot near a larger moon where the gravitational pull of the other moon (Dione here) and the planet cancel each other out."

Comments

It's a trap!

[Anonymous Coward]

That's no Trojan moon...

Trojan Moon!

[Evil W1zard]

Yikes better update my anti-virus. Don't want to get infected by W32.Polydeuces.A@mm now.

Naming & Mythology

[ornil]

I was a bit surprised about the name Polydeuces, because he (the mythological character) had little to do with Troy. However, it turns out that there's another Trojan moon called Helene (now this makes sense!), and Polydeucues is Helene's brother.

Re:Why Greek / Roman names?

[mickyflynn]

Because 'planet' is a greek name meaning 'wanderer.' Thte planets were thought to be the gods. Therefor, they named them with those names. Western civilization is largely inherited from the Greeks and the Romans. We kept the names. Besides, why the hell would we call Jupiter Lugh or Woden? It'd be weird.

All depends on your point of view

[FunWithHeadlines]

SATURN (Galactic News Agency) - The inhabitants of Saturn have announced that they have finally named the moon orbiting the third planet from the sun in their star system. The moon, named Xkeysdy, orbits the blue planet widely known as !3kd8dgh, which renders in Standard Galactic as "that wreteched place full of pushy peons."

When asked why they had named the moon now after millenia of observation, one student from Saturn's top university said, "Why not, you know? I mean, like, we had named everything else of importance, dude. Even the unimportant places. So like this was all that was left."

No comment could be received from inhabitants of !3kd8dgh, since they don't speak Standard Galactic. Moreover, they laughably think they are the only inhabitanted planet in the system, and it's considered taboo to disabuse them of this ignorance.

Fun with Newton & Lagrange

[C Siren]

Ok -- Newton's 1st & 2nd laws tell you that if you have unbalanced forces acting on an object (like a moon), that will result in an acceleration on that object. Acceleration is change in velocity, i.e. speed and direction. A moon going around in an orbit is constantly changing direction and needs a particular centripetal acceleration to stay in that orbit.

In celestial mechanics, Lagrange points come up in the three-body problem, where you have two large bodies (eg Sun and planet, planet and large moon) and one small object (a Trojan asteroid, spacecraft, new Saturn moon).

Lagrange points are the five places relative to the two large objects, where the third object will be held at the same position - relative to those two objects - in its orbit. In other words, there will be a net force on the third object that will result in it accelerating around the largest object at the same rate as the second largest object.*

A Lagrange point is stable if an object near by the L point will tend to be pulled towards or orbit around that point if it's a bit off the exact point. The L point is unstable if the object tends to be pulled further away from it once it wanders a little away.

The L1 point (in between the two large bodies), L4 and L5 points (60 deg ahead and behind the orbiting large body) are stable, the L2 and L3 points are unstable. Many of our solar observing spacecraft get sent to orbit the L1 point.

*(Center of mass discussion left out for relative simplicity)