Planet Earth

The Earth is 4.54 billion years old. Life on Earth is thought to have begun soon after formation of the oceans (4.41 billion years ago), as early as 4.28 billion years ago.

The Earth is the third planet from the sun at a distance of 92,955,807.3 miles. The planet completes one revolution around the Sun every 365,256 days, traveling 584 million miles at an orbital speed averaging 67,000 miles per hour. Earth rotates once every 23 hours, 39 minutes and 4.1 seconds, spinning 1,040 miles per hour at the equator.

The highest point on the planet Earth is the summit of Mt. Everest in the Himalayen Mountain range at 8,848 meters (29,028 feet - 5.49 miles) above sea level. The Mariana Trench is the deepest part of the ocean. The area includes a depth of 10.9 km (6.77 miles).

Earth's Atmosphere

Troposphere 0-12 km (0-7 miles)

Stratosphere 12-50 km (7-31 miles)

Mesosphere 50-80 km (31-50 miles)

Thermosphere 80-700 km (50-440 miles)

Exosphere 700-10,000 km (440-6200 miles)

The atmosphere carries a small quantity of all Earth's oxygen, about 0.35% of the entire amount. In the atmosphere, oxygen is released by photolysis. Photolysis occurs when ultraviolet radiation from the sunlight breaks apart oxygen-containing molecules such as nitrous oxide and atmospheric water to release free oxygen. Surplus oxygen recombines with other oxygen molecules to form ozone.

The biosphere carries the smallest quantity of all earth’s oxygen, about 0.01%. In the biosphere, the major oxygen cycles are photosynthesis and respiration. In these two processes of the oxygen cycle, it is interconnected with the carbon cycle and the water cycle. During photosynthesis, plants and planktons use sunlight energy, water, and carbon dioxide to make food (carbohydrates) and release oxygen as a by-product. As such, plants and planktons are the main producers of (free) oxygen in the ecosystem. They take in carbon dioxide and give out oxygen. Plants are estimated to replace about 99% of all the oxygen used."

The lithosphere (Earth's crust) carries the largest quantity of all earth’s oxygen, about 99.5%, because it is a constituent of the earth’s lands, soils, organic matter, biomass, water, and rocks.

Oxygen constitutes 49.2% of the Earth's crust by mass as part of oxide compounds such as silicon dioxide and is the most abundant element by mass in the Earth's crust. It is also the major component of the world's oceans (88.8% by mass).

More than 97% of the earth's water is found in its oceans. The remainder is freshwater, two-thirds of which is frozen within the earth's polar regions and mountain snowpacks. It's interesting to note that even though water covers the majority of the planet's surface, water accounts for a mere 0.023% of the earth's total mass. > Black Book > Planet Earth