This discovery clearly amazed the University of California Berkeley astronomers who observed Neptune, namely Ned Molter and Imke de Pater.
According to their observations, the storm was about 9,000 miles and lasted from June 26 to July 2, 2017. They also capture photos of Neptune's storm and increase its brightness to see more clearly the storm.
"We think this is the bright cloud that usually appears in Neptune, but when closer inspection is not a cloud, we have never seen a big swirl like this, even touching the planet's equator," Molter was quoted as saying by Gizmodo.
Both Molter and De Pater said it would investigate the complex storm that occurred on the fourth largest planet in the Solar System. By studying the motion of the storm, they hope to know the characteristics of Neptune known as the windy planet.
Earlier in June 2016, NASA's Hubble Telescope also found an oddity on Neptune's face. At that time, Neptune showed a dark vortex (size black) with the size of the United States.
The whirls are created not without events. Scientists say the vortex is thought to grow in Neptune over the past 22 years.
This vortex initially appeared in 1980. At that time, Hubble and Voyager telescopes had captured the appearance of a vortex that still has a small size.
Over time, scientists have the theory that this vortex grows from the formation of air from a molten ice gas in Neptune's atmosphere.