Next week, on Monday, May 9, skywatchers on Earth will be able to see Mercury make its way across the surface of the sun. The so-called transit of Mercury occurs only about 13 times every century, and the next one won’t take place until 2019.

The rare pass will be visible either partially or in full throughout most of the world. The event will not be visible in Japan and other parts of eastern Asia; Oceania and the nearby island nations; or Antarctica, according to a statement from the Royal Astronomical Society (RAS). However, viewers in those areas can watch the event online.

Because Mercury and Venus are the only solar system planets that lie between the Earth and the sun, they are the only planets that transit the star as seen from Earth. READ MORE