8.6.2004

On the 8th of  June 2004, it will be 122 years since an event, that no alive person has ever had an opportunity to observe. That day, at about 05:19 ZULU, a small black circle will appear on the solar disk. This circle will slowly travel over the bright disk and after that, at about 11:23 ZULU, it will disappear again. A long-awaited Venus’s transit over the Sun will take place.

When do the transits happen?

The Earth rotates around the Sun in a plane, which is called the ecliptic. The routes of other planets are more or less declined respectively to this plane (Venus’s declination is 3.39°). The intersections of the planet’s route with the ecliptic is called ascending (or descending) nod. It depends on whether the planet descends (or ascends) below (or above) the ecliptic. The transit can be executed only if both following conditions are fulfilled: 1) Venus is in a nod of its route (i.e. in the plane of the ecliptic), 2) The Earth, the Sun, and the nod of the Venus’s route lay in one line (which always happens at the beginning of June and December). Only in that time we can observe the transit of the planet’s dark disk over the Sun. The period of transit repetitions is 243 years, but within this period, repetitions take part after 105.5 years, then after 8 years, then after 121.5 years and finally after 8 years again. From the statistical angle of view, this event happens 1.2 times per century.