Mars has a striking(llamativo) red appearance, and in
its most favorable position for viewing, when it is opposite the sun, it is
twice(dos veces, el doble) as bright as Sirius, the
brightest star. Mars has a diameter of 4,200 mi (6,800 km), just over half
the diameter of the earth, and its mass is only 11% of the earth's mass. The
planet has a very thin(delgada, fina) atmosphere
consisting mainly(principalmente) of carbon dioxide, with
some nitrogen and argon. Mars has an extreme day-to-night temperature
range(rango de temperatura día-noche), resulting from
its thin atmosphere, from about 80°F (27°C) at noon(mediodía)
to about -100°F (-73°C) at midnight; however, the high daytime temperatures
are confined(limitadas) to less than 3 ft (1 m) above the
surface.
Surface Features
A network of linelike markings(marcas que semejan líneas)
first studied in detail (1877) by G. V. Schiaparelli was referred to by him
as canali(canales), the Italian word meaning “channels” or
“grooves(ranuras, surcos).” Percival Lowell, then a
leading authority on Mars, created a long-lasting(duradera)
controversy by accepting these “canals” to be the work of intelligent
beings(seres inteligentes). Under the best viewing
conditions, however, these features are seen to be smaller, unconnected
features(rasgos, características sin conexión). The
greater part of the surface area of Mars appears to be a vast desert, dull(apagado)
red or orange in color. This color may be due to(debido a)
various oxides in the surface composition, particularly those of iron.
About one fourth(un cuarto) to one third of the
surface is composed of darker areas whose nature is still uncertain.
Shortly after(poco después de) its perihelion Mars has
planetwide dust storms(tormentas de polvo de la anchura de un
planeta) that can obscure(oscurecer) all its
surface details.
Photographs sent back by the Mariner 4 space probe show the surface of Mars
to be pitted with(estar llena de) a number of large
craters, much like(muy parecido a) the surface of our
moon. In 1971 the Mariner 9 space probe(sonda) discovered
a huge(enorme) canyon, Valles Marineris. Completely
dwarfing(empequeñeciendo) the Grand Canyon in Arizona,
this canyon stretches for 2,500 mi (4,000 km) and at some places is 125 mi
(200 km) across and 2 mi (3 km) deep. Mars also has numerous enormous
volcanoes—including Olympus Mons (c.370 mi/600 km in diameter and 16 mi/26
km tall), the largest in the solar system—and lava plains(llanuras
de lava). In 1976 the Viking spacecraft(nave espacial)
landed on Mars and studied sites(escenarios, terrenos) at
Chryse and Utopia. They recorded a desert environment(ambiente
desértico) with a reddish(rojizo) surface and a
reddish atmosphere. These experiments analyzed soil samples(muestras
del terreno) for evidence of microorganisms or other forms of
life; none was found. In 1997, Mars Pathfinder landed on Mars and sent a
small rover(robot mecánico que se mueve y recoge muestras),
Sojourner, to take soil samples and pictures. Among the data returned were
more than 16,000 images from the lander(lit. aterrizador)
and 550 images from the rover(analizador), as well as more
than 15 chemical analyses of rocks and extensive data on winds and other
weather factors. Mars Global Surveyor, which also reached Mars in 1997, has
returned images produced by its systematic mapping(mapeo,
reconocimiento) of the surface. The European Space Agency's Mars
Express space probe went into orbit around Mars in late 2003 and sent the
Beagle 2 lander to the surface, but contact was not established with the
lander. The American Spirit rover landed successfully in early 2004. |
Inglés
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Francés |
Alemán
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Italiano |
Otros
1 (A-E)
| 2 (F-L) |
3 (N-S)
| 4 (T-U)
Árabe |
Chino |
Esperanto
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Griego
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Japonés
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Portugués
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Rumano
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Ruso
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Catalán
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Euskera