Hong Kong (AsiaNews) - 12:49 today marked the last chance for the people of the territory to witness the rather rare transit of Venus across the disk of the sun. The transit occurs when the orbit of the second planet in our solar system passes between the sun and the earth. This phenomenon happens twice in a row, but at a distance of hundreds of years. The previous transit of Venus occurred in 2004 and between then and now in 2012. But next time will be in 2117 and in 2125.
The Hong Kong Observatory and the Space Museum offered the opportunity free of charge to anyone who wanted to view the passage with protective tools: looking directly at the solar disc can damage the eyes. The Observatory also released pictures on its website.
The phenomenon has a scientific and historical significance. The transits of the planets in the 17th and 18th century were used by astronomers of the time to measure the distance between the earth and the sun, now known to be 149.6 million kilometers.
The transit of Venus is helping NASA to find out more about the density of the planet, particularly looking at the so-called "halo" at the beginning of the transit. Many sites, in the U.S., Israel, in Bengal (India), Hong Kong, Shanghai, Japan streamed the transit live (webcast).
A similar phenomenon will occur in 2016, when there will be the transit of the planet Mercury.