When we talk about planetary spots in the solar system, you may come up with the famous Great Red Spot on Jupiter. However, do you know that the planet Neptune also has some dark spots?

The dark spots on Neptune are some giant storms. They can last for years after they appeared. Astronomers have observed several dark spots in the past thirty years. These dark spots would appear at mid-latitude regions and remain stable due to the Coriolis force generated by the rotation of the planet. Then, they would migrate towards the equator and collapse as the Coriolis effect weakened. A new cycle would appear after a few years.

The current dark spot was discovered by the Hubble Space Telescope on the northern hemisphere on Neptune in 2018. In the subsequent observations, astronomers surprisingly found that the spot had changed its common southward motion to an abnormal northward motion. At the same time, a small isolated dark spot was found in a region closer to the equator. Some astronomers speculated that this small dark spot may be originated from the disruption of the big dark spot, and stopped it from moving towards the equator. Since the observation data is limited, the relation between these two spots and the direction of the motion is still unclear.