New Moons for Saturn

[aesmael]

    Emily Lakdawalla reports on the recent discovery of four (as yet unnamed) moons orbiting Saturn. So far that makes 60, none of which can make a decent cocktail.
    These new moons, like many of Saturn's, are about half the size of Deimos, which is pretty small. The curious should click through if they wish to see an animation of the discovery images for one of the newly found satellites.

Comments

[lost-angelwings.livejournal.com]

:O

Saturn has many moons o_o

[dclarion.livejournal.com]

This gets me to thinking: Has the ANSI or the ISO set down any criteria on what constitutes a moon? Deimos is pretty damned dinky, so these new moons would be demi-dinky. Are we getting to the point where Saturn would have tens of millions of moons, each the size of a Dodge Neon? If that is the case, what's the flap about Pluto? It's a chunk of rock whipping around the Sun (if a 248-year period meets anyone's definition of "whipping around"), so why not a planet?

[aesmael.livejournal.com]

Just what was on my mind as I posted too. I don't yet have substantive ideas for criteria.

As for Pluto, so far as I am concerned the term is minor planet, not dwarf planet (no one was using minor planet for asteroid anyway) and it is a subset of the class 'planet' which is divided into 'major' and 'minor'. And planet speaks mostly to mass and location, not composition.

[dclarion.livejournal.com]

And planet speaks mostly to mass and location, not composition.

Isn't Eris smaller, with a longer semi-major axis, than Pluto, though? I could be wrong, but I thought they were calling Eris a planet.

[aesmael.livejournal.com]

Eris is both larger and more massive than Pluto (hence the flurry of discussion following its discovery) and has a longer semi-major axis. At present it and Pluto and Ceres are officially dwarf planets which is officially something different to a planet and not a sub-classification.

What I meant when I said that was, many of the objects we label planets are different from each other in structure and composition (e.g. Earth vs. Jupiter vs. Saturn vs. Uranus vs. Eris), enough that I think 'planet' is really an umbrella term for a wide variety of objects.

I hope you will take it as a compliment when I say you are often difficult to respond to because thought and often research are required.

[dclarion.livejournal.com]

Eris is both larger and more massive than Pluto...

Aha! I stand corrected.

:o)

I hope you will take it as a compliment...

Oh, hell, yeah! I'll take it any way I can get it...

:o)