Venus is named after the Greek goddess of love and beauty, "Aphrodite", and is often referred to as earth's "sister planet"
due to various similarities including a virtually identical physical size, mass and density and a similar orbital period
around the sun. One of the most dramatic exceptions and characteric features of the second planet from the Sun is the
thick, dense and poisonous cloud composed of lethal carbon dioxide and sulphuric acid and which totally covers Venus. A
consequence of this cloud is that heat cannot escape back into space (albedo=0.65!) and, as a result, the planet has become
one huge and massive "Greenhouse" characterized with temperatures which exceed 450° C (or 890° F) and which are able to
easily melt lead. Similarly, devasting winds in the upper atmosphere approach 400 kph (250 mph).
Venus is different from most of the other planets in the solar system as it is characterized with a retrograde rotation which leads to the Sun rising in the West and setting in the East. Furthermore, its rate of rotation (243 days) is the slowest of any planet and slightly exceeds its rotation around the sun with its year being about 225 days. The surface is characterized with a crushing pressure approximately 100 times that on earth with notable land features including the 30-km wide and butterfly-shaped Aurelia Crater with minimal scattering of ejecta material due to the high surface pressure, the 6800-km long (!) Baltis Vallis which spans the lava plains of Venus and is interestingly 2.5 km wide from start to end, the 2-km high and 200-km wide Volcano Sif Mons which is active with lava flows and, finally, Aphrodite Terra which spreads about the equator and is characterized with both lava flows from the volcano Maat Mons and various distinct surface cracks.
Missions to Venus include Mariner 2 (1962), Venera 7 (1970), 8 and 9 (1975), and Magellan (1989). These probes have been instrumental in sending back surface images and a variety of atmospheric and surface measurements related to chemical composition, temperature, pressure, wind speeds and crater dimensions. For a complete and impressive list of satellite missions to Venus, click here.
2012 Transit: In contrast to the June 8th, 2004 transit opportunity of Venus against the Sun where the complete event was visible from Greece, the 2012 transit opportunity was only partially visible, for the latter two hours of the six-hr event and involving egress was possible at sunrise and immediately thereafter.
Transits by Venus against the sun are extremely rare, for no living individual on this planet has experienced such an event prior to 2004, and which occur in pairs spaced eight years apart and alternating between every 105.5 and 121.5 years. The last pair of such transits occurred in 1874 (Dec 9th) and 1882 (Dec 6th); the current pair of transits are in 2004 (June 8th) and 2012 (June 6th); and the following pair of transits will occur in 2117 (Dec 11) and 2125 (Dec 08). The transiting Venus in 2012 had an apparent diameter of 57.77 arc-seconds or approximately 1/37th that of the sun (1891.34") and lasted slightly under two hours beginning at sunrise for an observer based in Greece (see Table 1 below).
Please click on any of the thumbnails below for additional and related images in larger format.
Venus at Sunrise