Transit of Venus on June 5-6, 2012

On June 5-6, 2012, Venus will pass in front of the Sun. The 2012 transit of Venus will be the last chance to view this phenomenon for over 100 years.

During the transit, Venus passes between Sun and Earth. The planet becomes visible from Earth as a small dot against the Sun's disk. Although Venus is almost four times larger than the moon, it blocks a much smaller portion of the Sun's face than the moon does during a solar eclipse. This is because it is much further away from Earth.

Venus is the second planet from the Sun, Earth is the third. On a clear night Venus can also be seen as a bright “star” in the sky, especially shortly after sunset or before sunrise. This is why it is also referred to as “evening star” or “morning star”. It takes Venus 6 hours and 40 minutes to travel across the Sun's disk.

The alignment Earth - Venus - Sun has only occurred 7 times since the invention of the telescope: in 1631, 1639, 1761, 1769, 1874, 1882, and 2004.

The phenomenon can be experienced in recurring intervalls of 8 years, 121.5 years, 8 years, and 105.5 years. The last occurrence was 8 years ago, the next one will be in 105.5 years - on December 11, 2117.

Like observing solar eclipses, viewing the Venus pass before the Sun requires proper eye protection. The sun’s photosphere emits intense infrared and ultraviolet (UV) radiation. Just as UV radiation causes sunburn to skin, it can also damage the retinas in the eyes - but it does so at a much faster rate. The human eye can suffer permanent damage if it is exposed to direct sunlight for a few seconds.