Moons

[Spyder]

No argument with either of you guys...however, I would like to know what's under that ice on Europa....rock maybe? or, is it just one big ball of ice? If its rock, does that make it an ICE planet/moon or a ROCK planet/moon?

And, as for Charon, it is a planet-sized moon which probably affects Pluto nearly as much as Pluto affects it....kinda like a binary star system...soooo...is it a planet with a moon, or two planets? The question is even more valid if there is question of its orbit...it was mentioned that some think it has its own orbit...<shrug>

The idea I was originally was trying to point out was that moons don't usually have enough mass to hold an atmosphere. That is probably why, in the game, all moons are rock with no atmosphere (that and the sake of simplicity).


------------------
Spyder, Chairman of the Arachnid Consortium

[This message has been edited by Spyder (edited 01 March 2001).]

[Suicide Junkie]

Actually, half the moons are ice in SE4.

In fact, most moons are ice, but only if you're a Rock/None race.

[This message has been edited by suicide_junkie (edited 01 March 2001).]

[Shepherd]

Here's some numbers for you, guys.

Earth's moon has a 1738 km radius, making it a little over one-fourth the width of the earth. It's a rocky moon with a high density (around 3300 kg/m^3), giving it a surface gravity of about 1/6th G.

Ganymede (Jupiter), Callisto (Jupiter), and Titan (Saturn) are all icy moons, meaning that their average density is rather low, around 1500 kg/m^3. They're all around the same size, about 2600 km in radius, making them about 40% the width of Earth. Since they have approximately the same density and size, it's not surprising they have similar gravities, all about 1/7th of G. Note that although these moons have similar stats, they're pretty different otherwise; Titan has a methane atmosphere, and Europa may be liquid water under an icy shell.

While we're on Jupiter, let's not forget Io. This is a rocky moon about the same size as Earth's moon, but a little denser. Io's gravity is about 1/5.5 ths of G. Of course, Io being a *molten* rocky moon studded with volcanoes doesn't make it very habitable.

Finally we have Triton, the true gem of our solar system as far as moons go. Triton is about the same size as Earth's Moon, but is very dense, making it a rocky moon, although its surface is covered with ice. Triton's gravity is 0.29 G -- which sounds pretty comfortable. Unfortunately, at a surface temperature of 38 K (-235 Celsius, or -391 F), its atmosphere is mostly hydrogen and if it rains at all, it's raining liquid helium. So I'd have to say its planetary conditions are 'Unpleasant'.

The distinguishing feature between icy and rocky worlds seems to be their density, which has direct effects on their gravity, surface structure, and magnetic field. Icy moons are low gravity with no mag field. Rocky moons are higher gravity, with a mag field possible.

All data taken or calculated from the tables in my astrophysics book. If you find I've made a mistake somewhere, let me know!

[This message has been edited by Shepherd (edited 01 March 2001).]

[apache]

Well, by definition, rock is ice, a solid form of some silicate most likely. The truth is that ice planets are really planets that have things normally not frozen on Earth that are frozen on that planet. Ammonia, Methane, water, etc. are all stuff that is normally seen unfrozen on earth and most other planets in the system. But ice planets for whatever reason have these gasses/liquids actually frozen to, and acting as the surface. Europa has an ice surface, and some form of liquid ocean underneath. Under that, of course, is a solid basin of some sort.

[ColdSteel]

The earth's moon has quite a few unique features that have puzzled our scientists for quite a long time now. As was pointed out below, the ratio of the size of our moon to the earth is abnormally high as moons go. Truely our moon is a giant in our solar system. It rivals the gas giant's moons. There are a lot of other odd things about it like the fact that it always keeps one side facing the earth at all times as it orbits. Also, when one the Apollo missions set up a seismic station on the moon and then dropped part of the LEM back onto the moon after they left, the interior of the moon rang like a bell for hours, puzzling the hell out of the NASA geologists. There are also some other really, really strange things about our moon that cause the curious of mind to wonder..

[This message has been edited by ColdSteel (edited 01 March 2001).]

[raynor]

Cool info. If you find a website which talks about this, let me know. Interesting stuff!

[ColdSteel]

I borrowed Possum's webferret and immediately found this: http://keelynet.com/unclass/luna.htm

There are also some books on the subject. I read Don Wilson's books (referenced on the above site) 20+ years ago and was fascinated by them.

[raynor]

Thanks, much!

BTW, what did your search on? Lunar Anomaly?

Thanks again.

[Spoo]

*Cough*... BS...*cough*...

I hate to kill the theorey of a giant alien base inside the moon, but just about everything said in that article is dead wrong.

Of course it does make for a good laugh.

------------------
Assume you have a 1kg squirrel
E=mc^2
E=1kg(3x10^8m/s)^2=9x10^16J
which, if I'm not mistaken, is equivilent to roughly a 50 megaton nuclear bomb.
Fear the squirrel.

[Atrocities]

quote:

---

Does anyone else find it really annoying that the moons in the game are
A) Always small or tiny no matter how big the planet is

B) always have no atmosphere

It seems to me that I should be able to find moons with atmospheres, twin worlds, and so on, interesting places to explore, not just one repeat of earths moon after the next.

---

Do this, find a system with a few planets that have moons. Preferably more than one. Destroy the system with a star killer. Re-ignite a new star, and create planets out of the ruble. You may be surprised at what the moons are turned into.