Neptune is the eighth and most distant planet from the Sun. Until 1989, when the Voyager 2 spacecraft flew close to the planet and sent back information, we knew little about this distant object. Voyager’s pictures revealed an intensely blue planet with numerous cloud features. In addition to several white and wispy cloud regions, a dark region called the Great Dark Spot appeared near Neptune’s equator. All of these clouds make Neptune a beautiful and interesting object of study. It's not difficult to build a model of Neptune that shows off its features.
Select a ball to be Neptune. Any size is allowable, but make sure the ball is undecorated and has a surface that will hold paint.
Paint the entire surface of the ball with blue paint. Due to the methane in Neptune’s atmosphere, the principal color of Neptune’s clouds are blue.
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Use the white paint to draw long, streaky clouds. The white clouds are mostly in the region around Neptune’s equator.
Add dark-colored streaks. Slightly darker cloud bands are typical about halfway between the equator and the poles. Do not draw the streaks too dark and do not draw too many of them.
Use the dark-colored paint to draw the Great Dark Spot. The spot should be just below Neptune’s equator. Make the spot about twice as long as it is wide. The length should be about one-fifth of the ball’s width when you look directly at it.
Add in wispy white clouds around the Great Dark Spot and to the north of the equator. These clouds should be much smaller than the Great Dark Spot and nearly round.
Make sure the blue paint dries before you try to paint with any other colors. The overall color of Neptune must remain blue for accuracy. Look up the exact dimensions of Neptune and its Great Dark Spot if you want your model to be more accurate.
Keep in mind that your model is accurate for Neptune in 1989, when Voyager 2 flew past. Earth-based telescopes have since observed the disappearance of the Great Dark Spot and other features.