Hans Bruntt's Blog | Mercury Transit from Sydney

Thursday, 9. November 2006

Mercury Transit from Sydney11/09/2006 01:47 AM

The planet Mercury is the smallest planet in our solar system. It is also the planet that is closest to the Sun with an orbital period of 88 Earth days. The diameter of Mercury (4880 km) is about 40% that of the Earth and it is only 40% larger than our Moon. About 10-15 times every century Mercury passes in front of the Sun and we can see a partial eclipse (a transit) of the Sun. The transit is very tiny since the Sun is so immense in comparison, and thus it requires a small telescope to see it.

Johannes Kepler thought he saw an eclipse in May 1607, but it was in fact a much more common phenomenon. Dark sunspots are often seen on the solar surface and are due to magnetic fields near the solar surface.

Mercury is transiting the Sun as I am writing this, and it should be visible from Sydney. Unfortunately it is overcast this morning. Alas, the next transit that is visible from Australia is in 26 years (2032).

Mercury transit (2003) Surface of Mercury

The image above (left) shows a zoom in on the Mercury transit from 2003. The image on the right shows the surface of Mercury. Note that it is very similar to the cratered surface of the Moon.