Transit of Venus

No person alive today has seen the Transit of Venus, as it last happened in the year 1882, 122 years ago. As we live on earth, we can see only two planets transiting - Mercury & Venus. Transit of a planet is actually a very simple phenomenon to understand. When a planet is seen to move across sun (solar disk), it is called transit of the planet across solar disk. Transit are not visible without the help of telescopes, and that is the reason there are no mentions in ancient scripts, when viewed through a telescope, one sees a dense black spot on the sun, this spot appears to be moving, but very slowly. To see the transit through a telescope, solar filter lens is required, without such a filter one can become blind, so never see sun through the telescope without proper solar filters.

Another way of witnessing a transit is by projecting the sun through telescope on white paper. For this experiment no filters are required. Sun’s image is directly seen on the white board on paper, and if a transit is happening then a black spot is also seen. Along with this several other black markings will be seen, there are sunspots. So, how will one identify the planets black spot among many sun spots, as they all will be of almost some sizzle well, sunspots are dense black at the center but became blurred at the outer part, whereas planets black spot is dense black through out and is perfectly circular, sun spots may not be seen as perfect circles.

At the time of a transit, the planet while traveling in front of the sun actually blocks the light and that is why we see black spot over sun’s surface in other words it can be said absence of light. When the planet Mercury transits across the solar disk, its black spots size is very small, the reason for this is, mercury is a small planet and nearest to sun. Venus costs a bigger black spot because it is as big as Earth and is farther from sun than mercury is.

Transit of a planet happens only when sun, transits planet and earth come in one line and on the same side. We can see transits of Mercury & Venus because their orbits are inside the orbit of the Earth. But, if we go on Jupiter then we will be able to witness the transits of Mercury, Venus, Earth & Mars, and from Pluto, we will able to see all the planets transiting over the sun’s surface accept Pluto.

Transit of Mercury or Venus is a very interesting phenomenon and is also very important. It can be use to measure the distance, between Earth-Sun or Earth & the transiting planet. Johannes Kepler was the person who first calculated and predicted a transit, which was later proved to be accurate; unfortunately he was not alive to witness it.

Next transit of Venus will happen in 2012 June 6 and then the next pair of transits will take place in 2117 Dec 11 and 2125 Dec 08. Transit of Mercury happened in 2004 May 07 and next Mercury transit will take place in 2006 Nov 08.