The oceans of Earth are unique in our Solar System. No other planet in our Solar System has liquid water. The Earth's oceans are all connected to one another. Until the year 2000, there were four recognized oceans: the Pacific, Atlantic, Indian, and Arctic. In the Spring of 2000, the International Hydrographic Organization delimited a new ocean, the Southern Ocean. Oceans cover about 70% of the Earth's surface. The oceans contain roughly 97% of the Earth's water supply.