Key Points

The Earth's surface is mostly covered by water, approximately three-fourths. The remaining one-fourth is covered by land.

Oceans are the largest bodies of water on Earth. They are vast and interconnected, appearing blue from outer space, earning Earth the name 'blue planet'.

A large body of land is called a landmass, and a large continuous expanse of land is called a continent. Land covers a little over one-fourth of the globe.

Both oceans and continents play a vital role in shaping Earth's climate. They affect all aspects of life, including plants, animals, and human societies.

There are five major oceans: the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Arctic Ocean, and the Southern (or Antarctic) Ocean. These oceans are interconnected.

The Pacific Ocean is the largest, followed by the Atlantic Ocean. The Indian Ocean is the third largest, the Southern Ocean is fourth, and the Arctic Ocean is the smallest.

Oceans hold most of the planet's water, but it is salty and unfit for consumption. Freshwater makes up a very small proportion, leading to water scarcity concerns.

Oceans are home to diverse marine life, including algae, seaweeds, fish, dolphins, and whales. They produce over half of the world's oxygen, acting as the planet's lungs.

Oceans give rise to storms like cyclones, causing damage to coastal regions. Tsunamis, huge destructive waves from underwater earthquakes or volcanic eruptions, also originate in oceans.

Tsunamis are rare but destructive. Many countries collaborate on early warning systems, such as the Indian Ocean Tsunami Warning System, to protect lives and property.

The number of continents can vary between four and seven, depending on how landmasses are grouped. The most widely adopted count is seven continents.

The seven continents are Africa, Antarctica, Asia, Australia, Europe, North America, and South America. This list is most commonly used in practice.

Oceans and continents are not distributed equally between the Northern and Southern Hemispheres. The Northern Hemisphere generally holds more land than the Southern Hemisphere.

Islands are smaller pieces of land surrounded by water on all sides. Continents are also surrounded by water but are not considered islands due to their vast size.

Greenland is the largest island in the world. India possesses over 1,300 small islands, including the Andaman and Nicobar Islands and the Lakshadweep Islands.

Since 1981, India has conducted the Indian Antarctica Programme, establishing scientific base stations like 'Dakshin Gangotri'. Indian scientists research climate and environment in this cold continent.

Oceans have historically facilitated human migration, trade, and military campaigns. They have also been a source of food and inspired rich cultural tales and legends among coastal communities.

Oceans are polluted by millions of tonnes of plastic waste and suffer from overfishing, threatening marine life. Protecting oceans is a collective responsibility for the planet's future.

June 8 is designated as World Oceans Day by the United Nations. It reminds everyone of the ocean's crucial role as the planet's lungs, a food source, and a vital part of the biosphere.