New King of Moons.

[Zirconia]

Jupiter has lost its crown, Saturn now has the most moons.

Until they find more around Jupiter I suppose.

https://carnegiescience.edu/news/saturn-surpasses-...

[Gojira]

Zirconia said:

Jupiter has lost its crown, Saturn now has the most moons.

Until they find more around Jupiter I suppose.

https://carnegiescience.edu/news/saturn-surpasses-...

Cool - spotting 3 mile across rocks at that distance

Just wait for the next set of telescopes to come on line, and there will be lots more found

But how small does something have to be in order -not- to be a moon?

I predict a similar level of "Is it a moon or not?" fun to the "Is Pluto a planet?" arguments at some point...

[Eric Mc]

The International Astronomical Union does have a definition for moons. To qualify as a moon, the object has to be orbiting a planet, a planetoid (asteroid, comet, dwarf planet, minor planet etc) or even orbiting another moon.

Size wise, they are a bit vaguer. I did the Open University on-line course on moons a few years ago and the lecturers there said "nothing smaller than a toaster" - although that prompted a discussion on "what size toaster are we talking about?".

[Toaster]

Eric Mc said:

The International Astronomical Union does have a definition for moons. To qualify as a moon, the object has to be orbiting a planet, a planetoid (asteroid, comet, dwarf planet, minor planet etc) or even orbiting another moon.

Size wise, they are a bit vaguer. I did the Open University on-line course on moons a few years ago and the lecturers there said "nothing smaller than a toaster" - although that prompted a discussion on "what size toaster are we talking about?".

Did someone say Toaster

[GTO-3R]

A moon with it's own moon would be cool

[Eric Mc]

ash73 said:

Saturn has billions of moons, they just happen to be arranged in geometric rings.

The ring particles size wise fall below the IAU definition of a "moon".

[Eric Mc]

Nothing in astronomy is "official" in that there is no legal status behind any of these definitions. However, there are conventions and rules of thumb used all the time - otherwise there would be utter confusion and over complexity. It's the same issue that has caused problems over whether Pluto is a planet or not.

These definitions are useful as they help establish what items need to be tracked separately and/or given individual names or numbers. I would go with what Professor David Rothery said in the moons course I took part in. He is a planetary and moon specialist and it was he that said "below toaster" size was not worth classifying as a moon. If you want to debate it with him, I am sure you can contact him at the Open University - but I am sure he has more important things to be getting on with.

[geeks]

Eric Mc said:

ash73 said:

Saturn has billions of moons, they just happen to be arranged in geometric rings.

The ring particles size wise fall below the IAU definition of a "moon".

Also if you had looked at Saturn in the time of the dinosaurs there would have been no rings but an extra moon. In a number of thousand years there will be no rings left, we are by fluke here at the right time to observe them.

Sorry if you already knew this I just like this factoid.

[Eric Mc]

geeks said:

Also if you had looked at Saturn in the time of the dinosaurs there would have been no rings but an extra moon. In a number of thousand years there will be no rings left, we are by fluke here at the right time to observe them.

Sorry if you already knew this I just like this factoid.

That is more of a surmising rather than a hard fact. We are still a long way from understanding how the rings formed.

[geeks]

Eric Mc said:

geeks said:

Also if you had looked at Saturn in the time of the dinosaurs there would have been no rings but an extra moon. In a number of thousand years there will be no rings left, we are by fluke here at the right time to observe them.

Sorry if you already knew this I just like this factoid.

That is more of a surmising rather than a hard fact. We are still a long way from understanding how the rings formed.

I though Cassini had helped confirm it?

[Eric Mc]

Not really. It’s given us better information on the rings as they are now. How and when they formed and how long they will last is still uncertain.

Edited by Eric Mc on Thursday 10th October 08:56

[Zirconia]

https://www.universetoday.com/143668/astronomers-f...

Another description of the Moons. Interesting the prograde and retrograde differences. But then Saturn is big, Jupiter bigger, bet there are many eyes now applying this to that giant.

[StanleyT]

Online competition to name them on the Carnegie site.

Refrained from ManInTheMoonMcMoonFace and have submitted "Toasty" as a suggestion for a moon name!

[geeks]

Eric Mc said:

Not really. It’s given us better information on the rings as they are now. How and when they formed and how long they will last is still uncertain.

Edited by Eric Mc on Thursday 10th October 08:56

That last bit definitely isnt true. https://solarsystem.nasa.gov/news/794/nasa-researc...

[Chester35]

I guess we will soon be arguing over dwarf moons.

The issue with labeling something a moon or planet is that it takes a human perspective, our moon and our history, into categorising all the millions of objects, big or small, that go around the sun.

[Eric Mc]

geeks said:

Eric Mc said:

Not really. It’s given us better information on the rings as they are now. How and when they formed and how long they will last is still uncertain.

Edited by Eric Mc on Thursday 10th October 08:56

That last bit definitely isnt true. https://solarsystem.nasa.gov/news/794/nasa-researc...

Nothing in science is ever certain. The latest evidence points to the fact that the rings may not last an awful lot longer. But it's not a certainty. For example, we know that at least one ring of Saturn is continually being replenished by water eruptions from the moon Enceladus. There is still a lot to be learned about what forms and what sustains planetary ring systems.

It does seem that rings might be short lived phenomena - but we aren't sure about such matters. We already know that two other planets in our solar system possess rings - Jupiter and Uranus. Neither of their ring systems are as extensive or as spectacular as Saturn's but they do exist.

[Eric Mc]

And the name is allocated based on its size. It's just not practical to allocate names to things smaller than a pebble.