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Phases of ice. hide. Log-lin pressure-temperature phase diagram of water. The Roman numerals correspond to some ice phases listed below. The phases of ice are all possible states of matter for water as a solid. Variations in pressure and temperature give rise to different phases, which have varying properties and molecular geometries.
Virtually all of the ice on Earth is of a hexagonal crystalline structure denoted as ice I h (spoken as "ice one h"). Depending on temperature and pressure, at least nineteen phases (packing geometries) can exist. The most common phase transition to ice I h occurs when liquid water is cooled below 0 °C (273.15 K, 32 °F) at standard ...
Timeline of glaciation. Appearance. Climate history over the past 500 million years, with the last three major ice ages indicated, Andean-Saharan (450 Ma), Karoo (300 Ma) and Late Cenozoic. A less severe cold period or ice age is shown during the Jurassic - Cretaceous (150 Ma). There have been five or six major ice ages in the history of Earth ...
Concerns that a new ice age was approaching was revived in the 1950s. [14] During the Cold War, there were concerns by Harry Wexler that setting off atom bombs could be hastening a new ice age from a nuclear winter scenario. [15] J. Murray Mitchell showed as early as 1963 a multidecadal cooling since about 1940. [1]
The Wegener–Bergeron–Findeisen process (after Alfred Wegener, Tor Bergeron and Walter Findeisen []), (or "cold-rain process") is a process of ice crystal growth that occurs in mixed phase clouds (containing a mixture of supercooled water and ice) in regions where the ambient vapor pressure falls between the saturation vapor pressure over water and the lower saturation vapor pressure over ice.
251.9. Permian–Triassic extinction event. 199.6. Triassic–Jurassic extinction event, causes as yet unclear. 66. Perhaps 30,000 years of volcanic activity form the Deccan Traps in India, or a large meteor impact. 66. Cretaceous–Paleogene boundary and Cretaceous–Paleogene extinction event, extinction of dinosaurs. 55.8.
Sea ice is a composite material made up of pure ice, liquid brine, air, and salt. The volumetric fractions of these components—ice, brine, and air—determine the key physical properties of sea ice, including thermal conductivity, heat capacity, latent heat, density, elastic modulus, and mechanical strength. [ 16 ]
An illustration of ice age Earth at its glacial maximum. A "greenhouse Earth" is a period during which no continental glaciers exist anywhere on the planet. [6] Additionally, the levels of carbon dioxide and other greenhouse gases (such as water vapor and methane) are high, and sea surface temperatures (SSTs) range from 28 °C (82.4 °F) in the tropics to 0 °C (32 °F) in the polar regions. [7]