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Possible organic compounds found in Mars crater rocks

A study published in Science analyses multiple rocks found at the bottom of Jezero Crater on Mars, where the Perseverance rover landed in 2020, revealing significant interaction between the rocks and liquid water. Those rocks ...

Why do some dogs need high chairs, and how can genetics help?

Some dogs have to eat in a high chair—or, more specifically, a Bailey Chair. The chair keeps them in a vertical position while they eat so that gravity can do the work their bodies can't: moving food from the mouth to the ...

Refining the analysis of MRI contrast agents

You can keep your best guesses. Engineers at Rice University's George R. Brown School of Engineering are starting to understand exactly what goes on when doctors pump contrast agents into your body for an MRI scan.

Mars: Could life itself have made the planet uninhabitable?

Four billion years ago, the solar system was still young. Almost fully formed, its planets were starting to experience asteroid strikes a little less frequently. Our own planet could have become habitable as long as 3.9 billion ...

Magnesium ions slow down water dynamics on short length scales

The presence of ions affects the structure and dynamics of water on a multitude of length and time scales. New results from ultrafast spectroscopy and theoretical analyses show that the water environment of specific pairs ...

Listening to the song of melting glaciers

This is it, we have reached the bottom of the glacier. It is 327m under our feet. After drilling into the ice for six hours, our hot-water jet blasts into the sediment. The hose that connects it to the surface stops rolling ...

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Water

Water is a ubiquitous chemical substance, composed of hydrogen and oxygen, that is essential for the survival of many known forms of life. In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71% of the Earth's surface. On Earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below ground in aquifers and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation. Saltwater oceans hold 97% of surface water, glaciers and polar ice caps 2.4%, and other land surface water such as rivers, lakes and ponds 0.6%. A very small amount of the Earth's water is contained within biological bodies and manufactured products. Other water is trapped in ice caps, glaciers, aquifers, or in lakes, sometimes providing fresh water for life on land.

Water moves continually through a cycle of evaporation or transpiration (evapotranspiration), precipitation, and runoff, usually reaching the sea. Winds carry water vapor over land at the same rate as runoff into the sea. Over land, evaporation and transpiration contribute to the precipitation over land.

Clean, fresh drinking water is essential to human and other lifeforms. Access to safe drinking water has improved steadily and substantially over the last decades in almost every part of the world. There is a clear correlation between access to safe water and GDP per capita. However, some observers have estimated that by 2025 more than half of the world population will be facing water-based vulnerability. Water plays an important role in the world economy, as it functions as a solvent for a wide variety of chemical substances and facilitates industrial cooling and transportation. Approximately 70 percent of freshwater is consumed by agriculture.

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