If you are lucky enough to have clear skies Tuesday evening, you can witness a rare astronomical event that will not recur for more than a century. Venus, the Earth's neighboring planet, will pass in front of the sun.
The historical event during which the second planet from the sun flies by as a small black dot on the sun's surface will not happen until the year 2117.
Every 19 months Venus passes between the Earth and the sun. Since the orbit of Venus is tilted relative to that of the Earth, most of the time, Venus passes just above or below the sun. However, it is only during the transit of Venus, does the planet pass directly between the earth and the sun.
According to scientists, transits of Venus come in pairs spaced eight years apart. The time between the pairs is 122 years and then 105 years. Today's transit is the second of the 2004-2012 pair. Due to this pattern, only six Venus transits have been gazed since the invention of the telescope.
Based on the 18th-century transit, astronomers calculated the distance between the sun and the Earth to be 95 million miles (153 million kilometers) -- only slightly different from the true Earth-Sun distance of 93 million miles (150 million kilometers) according to National Geographic News.
The planet, often mistakenly referred to as the "morning star" or "evening star" due to its bright appearance, will take about six-and-a-half hours to travel across the face of the sun.
The transit begins around 3 PM Pacific Daylight Time (7 PM EST) on June 5. The timing favors observers in the mid-Pacific where the sun will be high overhead during the crossing. In the U.S., the transit will be at its best around sunset.
The event will be widely visible. In Europe, Africa, Asia and Australia, the transit can be observed in the morning of Wednesday, June 6.
As in a solar eclipse event, one needs to be careful not to stare at the sun directly during the event. Venus covers too little of the solar disk to block the blinding glare. Experts advise to use some type of projection technique or a solar filter. Many astronomy clubs have set up solar telescopes to observe the event.
Alternatively, binoculars or a telescope can be used to project the sun's image on to the ground or on a piece of cardboard to see the silhouette of Venus go across the sun.
by RTT Staff Writer
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