Alright children, lets learn about the basics of sticknodes lighting.
The other stuff will be explained soon, as gaseous space clouds and nebulae, lens flares and views on planets and things are stuff that start to get really complex.

Lets start off with planets. Me myself in particular uses simple shapes in order to make realistic art.
When your making a realistic circle, make sure you know where your light source is. Right now its going to be in your casual diagonal position from the ball. Im gonna make it a bit higher than being directly at the middle.

Now, for example lets make a gas planet.
This gas planet will be uranus like, it will have no features. It will be a gray gas planet.
So, lets say it has rings. Once again depending on where the light source is, it will have a different shadow. In this case the shadow will be directly below the rings, it will also cast a shadow on the planet. the rings will be flipped on the y axis and adjusted to the position of the planet. The way to make a shadow is to turn the figure’s color into black, lower the opacity and add some blur. Now for the planets shadow, what your gonna want to do is get a circular arc shape. In this case we will use bending nodes. We will use this to create an arc, which will be put behind the planet with the same method we used for creating the shadow on the rings. But since my light source is more above at the top, the shadow will be slightly more at the bottom.
For the atmosphere, choose the color. Add a slight tint to the planet and add a glow the same color as the tint. And there, you have a planet.

Might make a second post, this was a bit difficult to explain ;((
If i made some errors i will correct them
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