Background color: Black
Apply Noise at 110%
Apply BLUR MORE
Apply levels to even out the stars. It should look like so...

Create any shape you want with the Lasso Tool on a new layer and color it any shade of color you would like (make sure it doesnt over power the whole picture).
After doing so you need to add Gaussian Blur, at about 130% (if needed free transform any way you would like). It should look something like this.

Use any brushes necessary to create the Nebula in the background. (I have Custom brushes). Use a variety of brushes and colors to add definition to it and make it look colorful. Use the Adjustments tab to make any effects necessary, as well as the layer properties (i used alot of color Dodge)

Now it is time to create you planet. This is quite fun and it looks great. For this you are going to have to make a circle with the marquee tool. Once done so, use the paint bucket tool and fill in the circle with any texture you like. Make it look better by using Effects from the Filter Gallery. It should look something like this...

Once youve done so you are ready to add the shading. Create another circle marquee but just a little bit smaller. Color it black and unselect it. Add a gaussian blur to it at about 5-7%. Adjust it using free transform any size you want it to be depending on where your sun will be located. It should look like this.

To make the ring make a new layer and another circle marquee and draw a random design with a white paint brush. Use the twirl effect to twirl it around. IF needed apply it several times. Once that is done. De-select and Select the inner part of the Twirled circle and delete it. So that it looks like a doughnut. IT should look like this.

Now free transform the ring and flatten it to make it have depth. Angle it any way you want to make it look more realistic. Then place it on the planet and erase the part that goes behind the planet. It should look like this.!

Do further finalization's to the ring by adding shading and debris with brushes. It should end up something like this.

To make the asteroid you need to get a dark brown about (1c0903) brush with the hardness to the max (Circle Brush) and make a few asteroid shapes. Once you've got what you want you can copy and make as many as you need! Once that is done you are going to go to layer settings and click bevel and emboss and set the preffered settings (MAKE SURE THAT THE LIGHT PART MATCHES WITH WHERE THE SUN IS GOING TO BE). It should look like this.!

Now you are ready to make the sun. Go back to the First layer (black layer with stars) click Filter, Render, Lens Flare and place the flare so that half of it is coming out from the planet and the other half is behind the planet. the settings should be like so (50-300mm zoom, at 70%) It should look like this.

Now that most of the piece is complete, You are ready to add the comet in the background. Create a new layer and use a WHITE GRAINY brush. Draw a nice big Grainy dot and then click CTRL T to free transform, then at the top right you will see this grid shaped icon, click on that to go into WARP MODE. Once youve done so take ONE side of the grainy dot and move it as far left or right as you can, sometimes it may take a few times to get it to be the way you want. You can also add arch to it with warp mode. Finally to finish the comet off you can go to layer settings and do outer glow and add the color of your choice to make it look like there is an aura coming off of the comet. It should look somthing like this.