Water: A Substance with Life-Friendly Properties

By Edwin Cartlidge | Copyright: New Scientist | Persian translation: Mahmoud Haj-Zamani | Re-typed and re-edited: Sky and Weather Network

Water is the most abundant—and arguably the most important—liquid on Earth. Its importance, however, is not limited to biological phenomena. Compared with other substances on Earth, water has remarkable physical properties, many of which can be regarded as factors that make it particularly compatible with life. [source]

X-ray image of water molecules.

Image from the original article

The universe confronts us with many difficult mysteries, from the nature of dark matter and the origin of the universe to the search for a theory of everything. Yet an equally intriguing puzzle on a much smaller scale can be investigated in an ordinary kitchen. Fill a glass with cold water and drop in an ice cube. The familiar fact that ice floats is the first unusual property. Measure the temperature at different depths and another appears: near the ice the water is close to 0°C, while near the bottom it can be about 4°C. Water reaches its maximum density at about 4°C, an unusual behaviour that distinguishes it from ordinary liquids. [source]

Results from the Analysis of Water Vapor in Comet Chury

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Deuterium-to-hydrogen ratios at different locations in the Solar System.

Researchers with the European Space Agency, examining Rosetta spacecraft measurements of water vapour associated with comet “Chury,” found that the isotopic composition of the comet's water vapour differed markedly from that observed on Earth.

In terrestrial water, the article states, there is normally about one deuterium atom for every 7,000 ordinary hydrogen atoms. Deuterium is an isotope of hydrogen whose nucleus contains a neutron in addition to its proton.

In water vapour released by the comet, the source reports that the proportion was approximately three times higher—about one deuterium atom for every 2,000 ordinary hydrogen atoms.

The finding, which the article says had previously been suspected as a possibility, left the much-debated origin of Earth's water unresolved.