Neptune's Great Dark SpotImages transmitted to Earth by NASA’s unmanned Voyager 2 spacecraft, from a distance of 129,000,000 miles, reveal a consistent feature in Neptune’s atmosphere, an oval-shaped storm system near the Neptunian equator very similar in size and position to the Great Red Spot on Jupiter. This storm, quickly nicknamed the Great Dark Spot, allows Voyager scientists to estimate Neptune’s rotational period much earlier than expected. At the distance between Voyager 2 and Neptune, the smallest features on the planet that can be seen are at least 2,400 miles across, meaning the newly detected storm system is gigantic.