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| the Lion, a zodiacal constellation between Virgo and Cancer, containing the bright star Regulus |
| a star in an intermediate stage of evolution, characterized by a large volume, low surface temperature, and reddish hue |
| Mars2 (mɑːz) | |
| —n | |
| 1. | Also called: the Red Planet the fourth planet from the sun, having a reddish-orange surface with numerous dark patches and two white polar caps. It has a thin atmosphere, mainly carbon dioxide, and low surface temperatures. Spacecraft encounters have revealed a history of volcanic activity and running surface water. The planet has two tiny satellites, Phobos and Deimos. Mean distance from sun: 228 million km; period of revolution around sun: 686.98 days; period of axial rotation: 24.6225 hours; diameter and mass: 53.2 and 10.7 per cent that of earth respectively |
| 2. | the alchemical name for iron |
| Mars (märz) Pronunciation Key
The fourth planet from the Sun and the third smallest in the solar system, with a diameter about half that of Earth. Mars is the last of the terrestrial or inner planets and has notable similarities to Earth, including polar ice caps and a tilted axis that gives it seasons. However, it is significantly less dense than Earth and has no magnetic field, suggesting that it lacks a metallic core, and its atmosphere, made up mostly of carbon dioxide, is much thinner than Earth's. Mars has no surface water apart from a layer of permanent ice that underlies the seasonally changing caps of frozen carbon dioxide at its poles; there is, however, clear evidence of earlier water flows in the form of channels, outwashes, and canyons. Other surface features include numerous craters, especially in the southern hemisphere, along with very large volcanoes and extensive windblown dunes. Mar's reddish color is due to the abundance of hematite in its surface rocks. Its two small, irregular moons, Phobos and Deimos, may be asteroids captured earlier by gravitational attraction. See Table at solar system. |
In astronomy, the fourth major planet from the sun. Mars was named after the Roman god of war because of its red color. (See solar system; See under “Mythology and Folklore.”)
Note: Smaller than the Earth, Mars has polar ice caps and a surface that includes red sands.
Note: The Viking space mission, which placed landers on the surface of Mars, did not discover any signs of life.
Note: Mars has been, and remains, the focus of space research by NASA. Voyages to Mars, including multiple landings, are scheduled through the first decade of the twenty-first century.
| MARS multicast address resolution server |