The ocean's average depth is about 3,682 meters (12,080 feet), but it varies greatly, with the deepest point being the Challenger Deep in the Mariana Trench, plunging to nearly 11,000 meters (36,000 feet) — deeper than Mount Everest is tall. Sunlight only penetrates the top 200 meters (the Sunlit Zone), leaving the vast majority of the ocean dark, cold, and under immense pressure.
What limits human exploration of deep-sea environments? The limitations of human exploration in deep-sea environments are primarily due to depth-related challenges, including increased pressure, decompression sickness risk, and orientation difficulties, which often require specialized equipment and training.
How deep is the ocean? At nearly seven miles, the deepest part is a mile longer than Mount Everest is tall.
The very deepest depth of the ocean is roughly 2,000 meters deeper than Mount Everest is tall—36,070 feet deep (10,994 m)! Each zone has a different mix of species adapted to its specific light level, pressure, temperature, and community.
The average depth of the oceans is about 4 km. More precisely the average depth is 3,688 meters (12,100 ft).
Challenger Deep, at approximately 36,070 feet (10,994 meters). How does it compare to the height of Mount Everest? Mount Everest is 29,029 feet (8,848 meters) tall. Everest would fit completely submerged in the Mariana Trench and still have over a mile (1.6 kilometers) of water above it.
Sea level will continue to rise globally well into the future as long as the planet continues warming from greenhouse gas emissions. For the United States, sea level rise will likely reach around 12 inches (1 foot) by 2050.
Summary: 2025 is a transformative year for ocean governance, marked by three landmark events: the UN BBNJ Convention entering into force, new WTO fisheries subsidies regulations taking effect, and the adoption of a historic political declaration at the 2025 UN Ocean Conference.
More than 70% of our planet is ocean – and 90% of that ocean is deep sea.
Animals of the Deep
At around 300 feet, no visible light can penetrate the water at all!
Today, over 80% of the global ocean (and 50% of the U.S. Ocean) is still unmapped, with even more unexplored. One of the biggest challenges of ocean exploration is the intense pressures in the deep ocean. In addition, zero visibility and extreme cold temperatures make it difficult to explore the vast ocean.
One-celled organisms called monothalamea have been found in the trench at a record depth of 10.6 km (35,000 ft; 6.6 mi) below the sea surface by researchers from the Scripps Institution of Oceanography. Data has also suggested that microbial life forms thrive within the trench.
We have a great deal more to learn about our ocean and what resides within it, but progress IS being made. We learn more and more each year. We continue to discover new features and creatures, clues to our past, and resources that can improve our future. But the ocean will never be fully explored.
Psalm 104:25-26 – “There is the sea, vast and spacious, teeming with creatures beyond number-living things both large and small. There the ships go to and fro, and Leviathan, which you formed to frolic there.” Psalm 95:5 – “The sea is his, for he made it, and his hands formed the dry land.”
The 7 biggest ocean mysteries scientists can't explain
Distribution of countries according to their share of the Earth's surface. The largest countries in terms of area are Russia (3.35%), Canada (1.96%) and China (1.88%). Together they occupy about 7.2% of the Earth's surface.
Scientists estimate that roughly half of the oxygen production on Earth comes from the ocean. The majority of this production is from oceanic plankton — drifting plants, algae, and some bacteria that can photosynthesize.
Size and Distance
Many stars are much larger – but the Sun is far more massive than our home planet: it would take more than 330,000 Earths to match the mass of the Sun, and it would take 1.3 million Earths to fill the Sun's volume.
Our Biggest Stories of 2025: From Climate Politics to AI and...
Climate Change. Climate change represents the fastest-growing and most intense threat facing the global ocean.
Summary: UC Santa Barbara researchers project that human impacts on oceans will double by 2050, with warming seas and fisheries collapse leading the charge. The tropics and poles face the fastest changes, and coastal regions will be hardest hit, threatening food and livelihoods worldwide.
Planet-warming greenhouse gas emissions are expected to rise to 75 billion tonnes a year by 2050 – a nearly 50 per cent jump from today. This will destabilize the climate and lead to a surge in heatwaves, which are expected to affect nearly everyone on Earth – some 9.2 billion people – by 2050.
Background. Approximately 180 million years ago, the supercontinent Pangea broke up, forming the Atlantic Ocean between continents. Since then, the Atlantic Ocean has been growing gradually — over the course of millions of years, it has expanded at a rate of about 1.5 inches per year, Insider said.
As with other climate hazards, local factors mean that cities will experience sea level rise at different paces. Cities on the east coast of the U.S., including New York City and Miami, are particularly vulnerable, along with major cities in South East Asia, such as Bangkok and Shanghai.