Oceans cover the majority of the Earth's surface, which is why the Earth appears blue from outer space. Oceans cover over 129 million square miles of Earth, which is about 65.7 percent of the Earth's surface. The deepest part of the oceans can reach a depth of over 6 miles, and the ocean contains 97 percent of the water available on the planet.
Although the ocean is actually one massive, interconnected body of water, scientists divide the ocean into five distinct divisions: the Atlantic Ocean, the Pacific Ocean, the Southern Ocean, the Indian Ocean and the Arctic Ocean. The Pacific Ocean is the largest of these, covering over 30 percent of the Earth's surface. The lowest point on the planet, the Mariana Trench, also lies on the floor of the Pacific Ocean at a depth of 35,840 feet below the surface.
The Atlantic Ocean covers about 15 percent of the Earth's surface and contains the shallow ocean regions of the Caribbean Sea, the Mediterranean Sea, the Baltic Sea and the Black Sea. The Southern Ocean surrounds the continent of Antarctica and covers about 4 percent of the Earth's surface.
The Arctic Ocean covers only 3 percent of the Earth's surface, making it the smallest ocean. The Indian Ocean covers 13.4 percent of the Earth's surface and has the warmest surface temperatures of any ocean.