June 5 and 6: Transit Of Venus Across The Sun

The transit of Venus is a very rare phenomenon and will next occur on June 5 and 6, 2012. If you happen to miss this extraordinary event, you will not have another opportunity within your lifetime since the next occurrence won’t be until the year 2117.

Explaining A Transit
In astronomy, a transit occurs when a smaller body passes in front of a larger one. During a transit, the smaller body appears as a dark object against the backdrop of the larger one. A transit is also known as a special type of solar eclipse but, due to the sheer size of the sun, only a small part becomes darkened. The only planets known to produce a transit are Venus and Mercury.
For a transit to occur in Venus, two things must happen:
1. Venus must be in inferior conjunction with the sun. This means that Venus must be located directly between the earth and the sun
2. Venus must cross Earth’s path. For this to occur, Venus must be tilted at an angle of 3.39 degrees
The bad news is that a Venus transit only lasts for three to seven hours. During the transit, expect Venus to appear bigger that it’s normal size due to the backdrop effect. However, the appearance of an increase in size is actually an optical illusion. Light from the sun is really being refracted by Venus’ dense atmosphere, making the planet appear to be stretched out.
There is one word of caution concerning the viewing: it is advisable not to look at the transit directly with your naked eyes as it can cause temporary blindness. To have the best view, use cross-polarized sunglasses.

Who Can See The Transit
Whether you experience the transit on June 5 or June 6 will depend largely on your geographical location. If you are in the western hemisphere, the transit will probably occur on the afternoon of June 5. If you are in the eastern hemisphere, the transit will be seen during the sunrise on June 6.


Of the many spectacular astronomical events that are expected in 2012, this is destined to be one of the most extraordinary. Since this is the only time within the next century to experience it, it is well worth the effort to make sure that you do not miss out on this once-in-a-lifetime event.

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