Pacific Ocean

The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It stretches from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east.

At 165,250,000 square kilometers (63,800,000 square miles) in area, the Pacific Ocean covers approximately 46% of Earth's water surface and about 32% of the planet's total surface area. It is larger than all of the Earth's land area combined. The centers of both the water hemisphere and the Western Hemisphere, as well as the oceanic pole of inaccessibility, are located within the Pacific.

The Pacific Ocean has an average depth of 4,000 meters, with its deepest point being the Challenger Deep in the Mariana Trench, which reaches a depth of over 10,900 meters. The Pacific also contains many major marginal seas, including the Philippine Sea, South China Sea, East China Sea, Sea of Japan, and others, each playing important roles in the lives of people living nearby.

Etymology

In 1513, Spanish explorer Vasco Núñez de Balboa crossed the Isthmus of Panama and saw a vast ocean, calling it the "Southern Sea." Later, in 1520, Portuguese explorer Ferdinand Magellan named it Mar Pacífico, meaning "peaceful sea," because the waters were calm when he reached it.

History

Important human migrations took place in the Pacific Ocean in prehistoric times. Modern humans first reached the western Pacific around 60,000 to 70,000 years ago. They moved from Africa to East Asia, then to Southeast Asia, the Philippines, New Guinea, and Australia. These early people used simple sea travel methods to cross large distances.

Model of a Fijian drua, an example of an Austronesian vessel with a double-canoe (catamaran) hull and a crab claw sail

Later, a group known as the Austronesian peoples began a major expansion from Taiwan around 3000–1500 BCE. They developed advanced boat technologies and sailed across the Pacific, reaching islands such as the Philippines, Mariana Islands, Palau, and Yap. They continued to explore and settle across Remote Oceania, reaching places like Tonga, Samoa, the Cook Islands, Tahiti, Hawaiʻi, Rapa Nui, and New Zealand by around 1200 CE.

Main articles: Peopling of Southeast Asia and Austronesian peoples

The Pacific also saw European explorers. Portuguese navigators first reached its western edge in 1512, and Spanish explorer Vasco Núñez de Balboa encountered its eastern side in 1513. Ferdinand Magellan crossed the Pacific in 1519–1521 as part of the first circumnavigation of the world. Over the next centuries, many more explorers from Spain, Portugal, the Netherlands, Russia, France, and Britain sailed across the Pacific, mapping its islands and coastlines.

Geography

Sunset over the Pacific Ocean as seen from the International Space Station. Tops of thunderclouds are also visible.

The Pacific Ocean separates Asia and Australia from the Americas. It stretches from the Antarctic region in the south to the Arctic in the north. This vast ocean covers about one-third of Earth's surface, with an area of 165,200,000 km² — larger than all of Earth's land combined.

The Pacific Ocean reaches from the Bering Sea in the Arctic to the Southern Ocean near Antarctica. At its widest point, it spans about 10,700 nautical miles from Indonesia to Colombia. The deepest point on Earth, the Mariana Trench, lies in the Pacific, almost 11,000 meters below sea level.

Water characteristics

The Pacific Ocean holds about half of the world’s ocean water, with an estimated volume of 714 million cubic kilometers. Its surface water temperatures range from just below freezing near the poles to around 30°C near the equator. Salinity also changes, being lowest near the equator due to heavy rainfall and highest in the southeastern part of the ocean.

Water in the Pacific moves in large circles called gyres: clockwise in the Northern Hemisphere and counter-clockwise in the Southern Hemisphere. Important currents include the warm Kuroshio Current that flows northward near Japan, and the California Current that brings cooler water southward along North America. The South Equatorial Current moves westward along the equator before turning southward near New Guinea.

Climate

The climate of the Pacific Ocean changes with location and season. In the southern and eastern parts, winds called trade winds are steady, but in the northern part, the weather is more different. For example, Russia’s east coast has cold winters, while areas near British Columbia stay milder because of how ocean currents flow.

In the warm parts of the Pacific near the equator, a pattern called the El Niño Southern Oscillation changes the weather. Scientists watch the temperature of the ocean’s surface near Hawaii to see if it is unusually warm or cool, which helps them understand weather changes. The Pacific Ocean is also where many strong storms, called tropical cyclones, happen. These include Pacific hurricanes that can affect Mexico and sometimes the southern United States, and typhoons that move toward parts of Asia. The Pacific has the most active areas for these storms.

Geology

Main articles: Geology of the Pacific Ocean and Pacific plate

The Pacific Ocean was first named by Abraham Ortelius, based on Ferdinand Magellan's description of its calm waters during his voyage from 1519 to 1522.

A key feature of the Pacific is the andesite line, which separates the deeper rocky areas in the center from the shallower, continental edges. This line runs along the western edge of islands near California, past the Aleutian arc, the Kamchatka Peninsula, the Kuril Islands, Japan, the Mariana Islands, the Solomon Islands, and New Zealand's North Island. Inside this line lies the Pacific Ring of Fire, a zone known for its many active volcanoes.

Economy

The Pacific Ocean's deep waters make it hard to collect minerals, but in shallow areas near coasts, people find useful resources. Near Australia, New Zealand, and several other places, they collect petroleum, natural gas, and pearls.

Fish are very important for many people who live near the Pacific. In warmer, shallower waters, fish like herring, salmon, sardines, snapper, swordfish, and tuna, along with shellfish, are caught for food. However, overfishing has become a big problem in some places, meaning too many fish are caught and some fish populations are getting very small.

Environment

The Pacific Ocean faces many environmental challenges. Micro plastic pollution is especially common in the northwestern part, near countries like Japan and China. The Great Pacific Garbage Patch between California and Japan is a huge area filled with floating plastic — about three times the size of France!

Marine pollution happens when harmful chemicals and particles enter the ocean, often through rivers carrying waste and farm fertilizers. This can create areas with little oxygen, called dead zones, which harm sea life. Marine debris, or litter, also harms ocean animals and can wash up on beaches.

The Pacific Ocean is also a concern for nuclear waste and deep-sea mining. In the past, many nuclear tests were done in areas like the Marshall Islands. Today, there are worries about deep-sea mining, which could damage deep ocean ecosystems and harm sea creatures. Protecting the ocean from these threats is very important.

Etymology

History

Geography

Water characteristics

Climate

Geology

Economy

Environment

List of major ports

Images