Venus. Beautiful, Venus.
I never tire of looking up to the heavens and seeing her rise in the East and go across the sky into the West (the Morning Star and the Evening Star), so brilliant, so spectacular, so close.
Size comparison of terrestrial planets (left to right): Mercury, Venus, Earth, and Mars.
This diagram shows the approximate relative sizes of the terrestrial planets, from left to right: Mercury, Venus, Earth, and Mars. Distances are not to scale.
A terrestrial planet is a planet that is primarily composed of silicate rocks. The term is derived from the Latin word for Earth, “Terra”, so an alternate definition would be that these are planets which are, in some notable fashion, “Earth-like”. Terrestrial planets are substantially different from gas giants, which might not have solid surfaces and are composed mostly of some combination of hydrogen, helium, and water existing in various physical states. Terrestrial planets all have roughly the same structure: a central metallic core, mostly iron, with a surrounding silicate mantle. Terrestrial planets have canyons, craters, mountains, volcanoes and secondary atmospheres. Source: http://solarsystem.nasa.gov/multimedia/gallery/terr_sizes.jpg
Cloud structure in Venus’s atmosphere, revealed by ultraviolet observations. Ultraviolet image of Venus’ clouds as seen by the Pioneer Venus Orbiter (February 26, 1979). The immense C- or Y-shaped features which are visible only in these wavelengths are individually short lived, but reform often enough to be considered a permanent feature of Venus’ clouds. The mechanism by which Venus’ clouds absorb ultraviolet is not well understood. Source: NSSDC Photo Gallery Venus (February 26, 1979) – http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-venus.html
Now, she is in inferior conjunction to her sister, planet Earth, as Venus is as close as she will come this year to being directly between Earth and the Sun. On March 27, 2009, take out your telescope and be prepared to view Venus during mid- to late afternoon.
Careful! Do not look towards Venus, with the Sun in your vision, with unprotected eyes. To view Venus during the day, find a shaded area to place your scope to set up viewing, to protect your eyes from blindness. Aim your scope at Venus in the late afternoon when both the Sun and Venus are low on the horizon (viewing Venus above the Sun), to see this magnificent celestial phenomenon. If you do not have a telescope, you may use binoculars, but, when viewing Venus, it is best to follow the procedures indicated in the following article to protect your precious vision:
VENUS AT ITS 8-YEAR BEST
Venus hung extraordinarily high and bright in the Northern Hemisphere’s evening sky during January and February, 2009. But in mid-March, Venus started to plunge toward the sunset horizon, appearing more than 1° lower on each successive evening.
But for telescopic observers, this is the most exciting possible time to view Venus. On March 27th, our sister planet will be at inferior conjunction — as close as it will come this year to being directly between us and the Sun. As that date approaches the crescent seems too thin to be real, and it sports exotic cusp extensions as shown at right. The crescent spans nearly a full arcminute from tip to tip in late March — big enough to be seen easily in steadily supported binoculars.
Near inferior conjunction, the only way to get a clear telescopic image of Venus is to view the planet in broad daylight. When doing this, you must be extremely careful not to aim your telescope (or its finderscope!) at the Sun, or you may end up permanently blind. By far the safest procedure is to view Venus in mid- to late afternoon, when both it and the Sun below it are getting lower in the sky. Place your telescope just inside the shadow of a building, so that no part of the scope is sunlit. Use binoculars or your finderscope to scan above or upper right of where the Sun would be if you could see it, and you’ll soon locate Venus. You can use our Interactive Sky Chart or your favorite planetarium software to find the precise distance and angle between Venus and the Sun on your date.
Once every 8 years — and this is one of them — inferior conjunction also provides a special treat for naked-eye observers. Because Venus passes more than 8° north of the Sun, it should be visible at both dawn and dusk for at least three days centered on March 23rd at latitude 40° north. The farther north you live, the longer the period of dawn-and-dusk visibility will be. Find a spot with unobstructed horizons to the east and west, and scout the sky with binoculars before attempting a naked-eye sighting.
This phenomenon of inferior conjunction does not occur often, so try to partake of this wonderful treat for the naked eye observers.
So make a date with Venus this coming late March 2009.
Don’t miss this special event.
It may be a while before we see another inferior conjunction of Venus.
Enjoy!
Magellan radar topographical map of Venus (false color)
Beneath Venus’ Clouds
If the thick clouds covering Venus were removed, how would the surface appear? Using an imaging radar technique, the Magellan spacecraft was able to lift the veil from the Face of Venus and produce this spectacular high resolution image of the planet’s surface. Red, in this false-color map, represents mountains, while blue represents valleys. This 3-kilometer resolution map is a composite of Magellan images compiled between 1990 and 1994. Gaps were filled in by the Earth-based Arecibo Radio Telescope. The large yellow/red area in the north is Ishtar Terra featuring Maxwell Montes, the largest mountain on Venus. The large highland regions are analogous to continents on Earth. Scientists are particularly interested in exploring the geology of Venus because of its similarity to Earth.
- Image from NASA website, and converted to PNG format
- Credit: Magellan Team, JPL, NASA.
Ann
