The Great Red Spot

The Great Red Spot was first reported by the British scientist Robert Hooke (1635–1703). It is a storm, a swirling hurricane or whirlpool, of gigantic dimensions (twice the size of the earth), at least 300 years old. It rotates once every six days and is accompanied by other smaller storms. Neptune has a similar storm called the Great Dark Spot.
How could a storm last for three centuries or more?
We know from our experience on the earth that hurricanes form over the ocean and may remain active there for days. Once they move over land, however, they are soon spent (albeit often destructively); the land mass disrupts the flow pattern and removes the source of energy. On Jupiter, however, there is no land. Once a storm starts, it continues indefinitely, until a larger storm disrupts it. The Great Red Spot is the biggest storm on the planet.