Making the world better, one answer at a time. Scientist used math to find Neptune. They saw neptune up in the sky and couldn't believe it. They did some calculations on where neptune would be an looked again and found out that neptune was right there. They named it Neptune because of the Roman god Neptune.He was the god of the blue seas.eptune was created by many gases that formed into one big planet. They say Neptune was also created by the big bang theory. The gases are called hydrogen, helium, water, and … ammonia. Improvement: Just to clarify-the gases actually formed into one big planet as a result of the Big Bang Theory.