Evidence of a wet Mars.The news from Mars is dripping with interesting clues about the planet's wet history. Mars nowadays has no large pools of liquid water on its surface, but evidence gathered over 30 years suggests that the planet used to have lots of flowing water. Now, the European Space Agency's Mars Express This article or section documents a current spaceflight. Details may change as the mission progresses. orbiting spacecraft has gathered information that suggests where and how long ago Mars' water flowed. The Mars Express orbiter carries a piece of equipment called a spectrometer spectrometer Device for detecting and analyzing wavelengths of electromagnetic radiation, commonly used for molecular spectroscopy; more broadly, any of various instruments in which an emission (as of electromagnetic radiation or particles) is spread out according to some , which analyzes the planet's surface. Over the last 18 months, the spectrometer has revealed two classes of surface minerals that were formed by water. The minerals cover large areas of Mars in multiple places. One type of mineral, which forms when molten rock spends a long time in contact with water, appears only on the oldest of Mars' landscapes. These areas date back to about 3.8 billion years ago. The other class of minerals appears only on younger terrain. Called hydrated hy·drat·ed adj. Chemically combined with water, especially existing in the form of a hydrate. Adj. 1. hydrated - containing combined water (especially water of crystallization as in a hydrate) hydrous sulfates, these minerals need just a brief dousing with water to form. They also require acidic acidic /acid·ic/ (ah-sid´ik) of or pertaining to an acid; acid-forming. acidic, adj having the properties of an acid; acid-forming properties. conditions. The evidence suggests that Mars has gone through at least two major climate phases over the years, astronomers Famous astronomers and astrophysicists include: Directory: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A
Since June, Mars Express has also been collecting data with a radar sounder. This tool sends out radar waves and reads the echoes that come back. It ends up with information about what's below the planet's surface. So far, the radar sounder has revealed that 98 percent of a 3-kilometer-thick (1.9-mile-thick) ring of ice at Mars' north pole North Pole, northern end of the earth's axis, lat. 90°N. It is distinguished from the north magnetic pole. U.S. explorer Robert E. Peary is traditionally credited as being the first to reach (1909) the North Pole. In 1926, Richard E. is made of frozen water. Despite the weight of the ice, however, the layer underneath it (called the lithosphere lithosphere (lĭth`əsfēr '), brittle uppermost shell of the earth, broken into a number of tectonic plates. The lithosphere consists of the heavy oceanic and lighter continental crusts, and the uppermost portion of the mantle. ) has, surprisingly, not sunk. This might be because the lithosphere is thick enough to support the ice. In another area, the radar sounder also revealed what seems to be an ice-filled crater buried underneath the surface in Mars' northern lowlands. The crater is big--about 250 kilometers (155 miles) wide and 1.5 to 2.5 kilometers (1 to 1.5 miles) deep. Several channels meet there. Scientists have long wondered what happened to all the water on the Red Planet. Buried, ice-filled craters might be part of the answer. http://www.sciencenewsforkids.org/articles/20051214/Note2.asp |
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