First, make a new doc and have the pixels the same size ( ex - 1000x1000 px) Start off with a new layer and fill the layer black with the paint bucket

Now go to Filter > Render > Lens flare. Set the precentage to 120 (or whatever you like) and click on 105 mm Prime as shown above.

Now go to Filter > Distort > Polar Coordinates and click on "Polar to Rectangular" at the bottom of the screen.

Now got to Image > Rotate Canvas > 180 degress, then go back to Polar Coordinates and this time, click on Rectangular to Polar and you'll get this sphere. Click on the Elliptical tool and get as close to the edge of the sphere as you can and hit shift+ctrl+I and hit delete.

Now all you should have is a sphere. Now to make it different colors, hit Ctrl+U, click on the Colorize box and make the sphere into any color you wish.

This is basically how I was able to do the glass atom and the globe. This have really helped me improve my digital art skills and I hope it will help you as well.