Page 44 - Ultimate Visual Dictionary (DK)

THE UNIVERSE

Mars TILT AND ROTATION OF MARS
Axial tilt
Perpendicular
Axis of of 24° to orbital plane
MARS, KNOWN AS THE RED PLANET, is the fourth planet rotation
from the Sun and the outermost rocky planet. In the
North Pole
19th century, astronomers first observed what were
thought to be signs of life on Mars. These signs Orbital
plane
included apparent canal-like lines on the surface, and
dark patches that were thought to be vegetation. It is
now known that the “canals” are an optical illusion,
MARS
and the dark patches are areas where the red dust that
covers most of the planet has been blown away. The fine dust particles are
often whipped up by winds into dust storms that occasionally obscure One rotation South Pole
takes 24 hours
almost all the surface. Residual fine dust in the atmosphere gives the
and 37 minutes
Martian sky a pinkish hue. The northern hemisphere
of Mars has many large plains formed of solidified SURFACE FEATURES OF MARS
volcanic lava, whereas the southern hemisphere has
Bright
many craters and large impact basins. There are also
water-ice fog
several huge, extinct volcanoes, including
Olympus Mons, which, at 370 miles (600 km)
across and 15 miles (25 km) high, is the largest Fog in canyon 12 miles
(20 km) wide at end of
known volcano in the solar system. The surface Valles Marineris
also has many canyons and branching channels.
The canyons were formed by movements of the
surface crust, but the channels are thought to have
Syria Planum
been formed by flowing water that has now dried
up. The Martian atmosphere is much thinner than
Earth’s, with only a few clouds and morning mists.
NOCTIS LABYRINTHUS (CANYON SYSTEM)
Mars has two tiny, irregularly shaped moons called
Phobos and Deimos. Their small size indicates that
Summit caldera
they may be asteroids that have been captured by consisting of
the gravity of Mars. overlapping
collapsed
volcanic craters
THE SURFACE
OF MARS
Gentle slope
produced by
lava flow

Cloud formation
OLYMPUS MONS (EXTINCT SHIELD VOLCANO)
MOONS OF MARS

Dark area where
dust has been
blown away by
wind South Surface covered PHOBOS DEIMOS
polar ice with red-colored Average diameter: 14 miles Average diameter: 8 miles
cap iron oxide dust Average distance from Average distance from
planet: 5,800 miles planet: 14,600 miles

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