Overview of Venus

Venus has often been called Earth's sister planet because of its similar size and proximity to Earth in the solar system. Below are some properties in reference to Earth values:

Orbital Distance   :   0.72  Earth's orbit
Orbital Period     :   0.62  Earth years
Rotation           : 243     Earth days (retrograde)
Mean Radius        :   0.95  Earth's radius
Mass               :   0.815 Earth's mass
Surface Pressure   :  90     atmospheres
Gravity            :   0.91  Earth's gravity

Image of Venus

The surface of Venus is normally hidden, perpetually shrouded in cloud cover, but the synthetic aperture radar (SAR) imaging system of Magellan is able to penetrate the cloud cover. One hemisphere view of Venus (225 K gif) created from Magellan radar images provides a spectacular view of the planet.

The orange-brown hues of the image are false color enhancements. They are used in order to mimic the color of the planet's surface as seen by Soviet Venera cameras. The central meridian of this projection is 180 degrees east.

(This image was generated by the Solar System Visualization
Project and the Magellan Science team at the Jet Propulsion 
Laboratory, Pasadena, CA)

Description of features seen in this image

Venus, like most of the terrestrial planets, can be divided into two broad physiographic regions: highlands and lowlands.

Highlands
- Regio (regiones, pl.) are topographically high regions, often hosting large shield volcanoes, and are thought to be areas of mantle upwelling.
- Terra (terrae, pl.) cover vast areas and have variable topographic relief, as continents do on Earth.
- Planum (plana, pl.) Lakshmi Planum is the only planum recognized on Venus. It is a 3-4 km high plateau, bordered by mountainous ridges.
There are four highland areas of Venus, (1) Ishtar Terra, (2) Lada Terra, (3) Aphrodite Terra and the fourth area defined by (4) Beta, Phoebe and Themis regiones (Ford and Pettengill, 1992) .
Lowlands
- Planitia (planitiae, pl.) are topographic low-lying regions, generally the most featureless on Venus in terms of tectonic and volcanic structures.

The bright equatorial belt seen across the image, broadly defines the largest highland region of Venus, called Aphrodite Terra . The darker regions to the north and south of Aphrodite Terra are lowland plains called Atalanta Planitia and Helen Planitia repectively.

Aphrodite Terra

Aphrodite Terra can be thought of as a large continent on Venus. It is composed of several highland regions, seen from left to right on the image:

At the extreme left is a highland area, Ovda Regio , and to the immediate right of it along the equator lies another called Thetis Regio .

The central area just below the equator hosts a series of northeast-trending curvilinear ridges and troughs with about 1-1.5 km of relief called Diana and Dall Chasma that extend to the northeast (right), just above the equator, to reach a bright highland region of Aphrodite Terra called Alta Regio . The elevation of Alta Regio is typically 3 km, but large volcanic edifices in the region reach much higher elevations. Chasmate appear to radiate away from the central part of Alta Regio, where Maat Mons , a large 9-km high volcano, is located.

More information about the landscape of Venus can be found in Solomon et al. (1992).

 go back to home page       go to introduction

                                 go to crater database

                                 go to corona database