A rare event is occurring on Monday: The planet Mercury is passing directly between the Earth and the Sun. This is called a transit, and it occurs only 13 times every 100 years. The last transit of Mercury was in 2016, and the next one won’t be until 2023, so you should take the chance to view this special astronomical event while you can.
Where can it be seen?
The transit is due to start at 12:34 UTC on November 11 and end around 18:05 UTC. Depending on cloud cover, the event can be viewed – even partially – from many countries, particularly in South America, Africa, south and west Europe, south and west Asia, and much of North America.
Obviously, looking directly at the sun is a terrible idea. So, for starters, don’t do that. If you’re lucky enough to find yourself somewhere within the region where the transit should be visible from, then you’ll need to equip yourself with binoculars or a telescope (even a light one should do the trick) but make sure you’ve added an effective sun filter over the lens beforehand.
If you don’t have access to a telescope then you can still follow the event online. The Solar Dynamics Observatory will be providing data about the transit to NASA, which will show near-real-time images and short movies of the event on the transit website.
Transits are not only fun cosmic events to observe, but they were also important in the development of early astronomical knowledge. It was by studying the transits of Mercury and Venus in the early 1600s that Johannes Kepler was able to see that the orbits of the planets are elliptical, not circular as previously believed.