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 to Antarctica in the south. It is bounded by the continents of Asia and Australia in the west and the Americas in the east.

The Pacific Ocean covers about 46% of Earth's water surface and 32% of the planet's total surface area. It is larger than all of the Earth's land areas put together. The centers of both the water hemisphere and the Western Hemisphere, as well as the oceanic pole of inaccessibility, are inside the Pacific.

The Pacific Ocean has an average depth of 4,000 meters. Its deepest point is the Challenger Deep in the Mariana Trench, which is over 10,900 meters deep. The Pacific also contains many major marginal seas, including the Philippine Sea, South China Sea, East China Sea, and Sea of Japan. These seas are important to the people who live near them.

Etymology

In 1513, Spanish explorer Vasco Núñez de Balboa crossed the Isthmus of Panama and saw a huge ocean. He called it the "Southern Sea." Later, in 1520, Portuguese explorer Ferdinand Magellan named it Mar Pacífico, meaning "peaceful sea." He chose this name because the water was calm when he arrived.

History

Important human migrations happened in the Pacific Ocean long ago. 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 boats to travel far 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 called the Austronesian peoples began a big journey from Taiwan around 3000–1500 BCE. They made good boats and sailed across the Pacific. They reached islands such as the Philippines, Mariana Islands, Palau, and Yap. They kept exploring and settling across Remote Oceania. They reached 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 sailors first reached its western edge in 1512. Spanish explorer Vasco Núñez de Balboa found 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. They mapped 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 cold Antarctic in the south to the icy Arctic in the north. This huge ocean covers about one-third of Earth's surface.

The Pacific Ocean reaches from the Bering Sea in the far north to the Southern Ocean near Antarctica. At its widest point, it spans about 10,700 nautical miles from Indonesia to Colombia. The deepest part of Earth, the Mariana Trench, lies in the Pacific.

Water characteristics

The Pacific Ocean holds about half of the world's ocean water. Its surface water temperatures range from very cold near the poles to warm near the equator. Salinity changes too, being lowest near the equator because of heavy rain 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 where you are and the time of year. In the south and east, steady winds called trade winds blow. In the north, the weather changes more. For example, Russia’s east coast has cold winters, while places near British Columbia stay milder because of how ocean currents flow.

Near the equator, a pattern called the El Niño Southern Oscillation changes the weather. Scientists watch the temperature of the ocean near Hawaii to learn about weather changes. The Pacific Ocean is 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 named by Abraham Ortelius. He heard about its calm waters from Ferdinand Magellan.

One special part of the Pacific is the andesite line. This line separates deeper rocky areas from shallower edges near land. It runs near California and 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 is the Pacific Ring of Fire. This area has many active volcanoes.

Economy

The Pacific Ocean's deep waters make it hard to collect minerals, but near coasts, people find useful resources. Near Australia, New Zealand, and 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 is a 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. Tiny pieces of plastic, called micro plastic pollution, are common near countries like Japan and China. The Great Pacific Garbage Patch between California and Japan is a very large area filled with floating plastic.

Marine pollution happens when harmful chemicals and particles get into the ocean, often through rivers carrying waste and farm fertilizers. This can create areas with little oxygen, called dead zones, which can 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, 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