Old Pictures from Celestia (locked)

[Hungry4info]

About the ambient light,

I actually think it's perfect. The low ambient light gives the impression of a darker, cold, lonely place, something very characteristic of a long-period gas planet's moon.

Anything in the solar system is explorable. Spacecraft can be sent to it and discover things, and image their surfaces. Humans can gain an understanding of what these things look like. LRO is giving us fascinating images of boulder-strewn landscapes, MRO gives us great high-resolution images of Mars. Cassini shows us wonders in the Saturn system, and so on and so on.

But imagine a moon system around, say, 47 UMa. Not only do we have no idea what's there (if anything), we'll never be able to know what these moons are like ("never" here being "not in the foreseeable future"), we'll never see their craters, study their geologies, we'll never know anything about them. There's just an inherent deep loneliness I get when I ponder such places. It's as if these places are hidden away into informational oblivion.

Reiko's images capture that fairly well. A cold, dark moon orbiting a gas planet, no one will ever know of its existence, much less what the moon is actually like.

[Fenerit]

I love these shots. It looks as some "retro" Urania's scifi booklets covers paintings.







For a complete list of image's covers;

http://www.mondourania.com/urania/uraniaelencopagine.htm

[Reiko]

Thanks for the input everybody. I try to make it dark and spooky like the moon in alien but can't get the color right.

[Reiko]

Janus VI (Where the Horta live)

[Reiko]

Some Earth-like worlds in the works.

[Reiko]

I finally got the double ring system to work. I tried the planet within planet trick again and it worked this time. I'm not sure why I couldn't get it to work before.
The only problem is the 2nd set of rings doesn't cast a shadow on the planet.

[bh]

I finally got the double ring system to work. I tried the planet within planet trick again and it worked this time. I'm not sure why I couldn't get it to work before.
The only problem is the 2nd set of rings doesn't cast a shadow on the planet.

Hi Reiko... looks nice but is surely impossible?

[fungun]

Oh, I don't know...it was real in Pitch Black....

[selden]

I wouldn't be surprised if multiple tilted rings could exist for a short time (thousands of years), but they wouldn't be stable over a long period of times (millions of years). The particles in the rings would eventually migrate to a ring system in a plane orbiting above the planet's equator and/or under the plane of the orbits of the most massive moon(s). It seems to me that a tilted ring would be unlikely to have an extremely complex structure since many of the gaps and bunches in Saturn's rings are caused by resonances with the orbits of multiple moons.

I suspect a not-very flat ring system could be created by a collision between an existing moon and an incoming comet, with gaps caused by collisions of smaller particles with the larger pieces.

Of course, as an artistic accomplishment, it looks quite good!

[eburacum45]

A T class methane brown dwarf



and an L class Lithium dwarf

[Hungry4info]

I wouldn't be surprised if multiple tilted rings could exist for a short time (thousands of years)

I would.

In an orbit, any particle must have the centre of gravity coplanar with the orbit. (As such, all geosynchronous satellites are over the equator).

[selden]

I wouldn't be surprised if multiple tilted rings could exist for a short time (thousands of years)

I would.

In an orbit, any particle must have the centre of gravity coplanar with the orbit. (As such, all geosynchronous satellites are over the equator).

Right.
The "center of gravity" of the orbits of the particles in the rings is effectively the center of the planet. That's always in the plane of their orbits. There are "restoring forces" which tend to cause the planes of those orbits to eventually rotate into the planet's equatorial plane, but that takes a long time and some way for the energy contained in the tilts of their orbits to be dissipated. That usually happens in collisions among the particles.

[Hungry4info]

So wouldn't the ring system spread out over the latitudes between it's current latitude and the negative latitude? Becoming more of a torus or belt than a ring? (thus, keeping the centre of planet coplanar with the orbits of the individual particles)

If a ring particle were to orbit in the same non-zero latitude, it should need a constant force keeping it at that latitude.

Edit:
Wait... I think all this confusion is on my part. Is that an image of two ring systems that don't intersect? Or two ring systems that are just inclined differently? I got the opinion that the two ring disks were parallel. Was I just looking at the image wrong?

[Cham]

Some star systems in formation (fully 3D volumetric sprite based models, with fluid-like animated differential rotation...) :





A gas giant in formation (with animated differential rotation in the dust belt, and animated turbulence in the gas giant) :

[Reiko]

I finally got the double ring system to work. I tried the planet within planet trick again and it worked this time. I'm not sure why I couldn't get it to work before.
The only problem is the 2nd set of rings doesn't cast a shadow on the planet.

Hi Reiko... looks nice but is surely impossible?

I don't know but I get the idea from the opening sequence to Superman Returns. Another odd planet they showed had a huge chunk missing and two three asteroid belts twisted around perpendicular to each other.

[ajtribick]

Some star systems in formation (fully 3D volumetric sprite based models, with fluid-like animated differential rotation...) :

Wow, those look fantastic, would really like to see this one in action... do the sprites have the same problem as the points when you zoom out?

[Cham]

do the sprites have the same problem as the points when you zoom out?

Nope ! Not in these cases. The colors and transparency are so that the sprites do fade away, when you move out.

[chris]

do the sprites have the same problem as the points when you zoom out?

Nope ! Not in these cases. The colors and transparency are so that the sprites do fade away, when you move out.

Does this mean that the point sprite fix that I sent you is working now?

--Chris

[Cham]

Does this mean that the point sprite fix that I sent you is working now?
--Chris

No, I was using 1.6.0. With some colors and transparency combinations, the problem doesn't show up (transparency must be pretty high).

[Spaceman]

Fantastic images everyone

A tribute to the Orion's Arm Universe

zapod.jpg

greenmars.jpg

luminare.jpg