Page 38 - Ultimate Visual Dictionary (DK)

THE UNIVERSE

Venus TILT AND ROTATION OF VENUS
Axis of
rotation Perpendicular
to orbital plane
VENUS IS A ROCKY PLANET and the second planet from
Axial tilt of 2°
the Sun. Venus spins slowly backwards as it orbits the Sun, North
Pole
causing its rotational period to be the longest in the solar
system, at about 243 Earth days. It is slightly smaller Orbital
than Earth and probably has a similar internal structure, plane
consisting of a semisolid metal core, surrounded by a
rocky mantle and crust. Venus is the brightest object in
RADAR IMAGE OF
VENUS the sky after the Sun and Moon because its clouds reflect
sunlight strongly. The main component of the atmosphere is carbon
dioxide, which traps heat in a greenhouse effect far stronger than that on One rotation
takes 243 days South Pole
Earth. As a result, Venus is the hottest planet, with a maximum surface
and 14 minutes
temperature of about 900°F (480°C). The thick cloud layers contain droplets
of sulfuric acid and are driven around the planet by winds at speeds of up to
220 miles (360 km) per hour. Although the planet takes 243 Earth days to
CLOUD FEATURES
rotate once, the high-speed winds cause the clouds to circle the planet in
only four Earth days. The high temperature, acidic clouds, and enormous Polar hood Dark, mid-latitude
atmospheric pressure (about 90 times greater at the surface than that on band
Earth) make the environment extremely hostile. However, space probes
have managed to land on Venus and photograph its dry, dusty surface.
The Venusian surface has also been mapped by probes with radar
equipment that can “see” through the cloud layers. Such radar maps
reveal a terrain with craters, mountains, volcanoes, and areas where
craters have been covered by plains of solidified volcanic lava. There
are two large highland regions called Aphrodite Terra and Ishtar Terra.

VENUSIAN CRATERS
Danilova
Cloud features swept
Ejecta (ejected around planet by
material) winds of up to 220
miles (360 km/h)
Central peak
Howe Dirty yellow hue
due to sulfuric acid Bright
in atmosphere polar band
FALSE-COLOR RADAR MAP Metis Regio Maxwell Montes Bell Regio Tethus Regio
OF THE SURFACE OF VENUS
Atalanta Planitia
Sedna Planitia Leda Planitia
ISHTAR TERRA
Eisila Regio Tellus Regio

Guinevere Planitia Niobe Planitia
Phoebe Regio
Ovda Regio
Alpha Regio
Thetis Regio
APHRODITE TERRA
Themis Regio
Lavinia Planitia Aino Planitia
Helen Planitia Lada Terra

36