Space.com: The Science of the 2019 Mercury Transit: How Astronomers Will Study the
Rare Celestial Event.
On Monday (Nov.11), observers and scientists in North America will have their last opportunity to view a rare celestial event for three decades.
Mercury will cross in front of the sun, as seen from Earth, a process known as a transit. Although the last transit of Mercury occurred only three years ago, the next won’t happen until 2032 and won’t be visible from North America. These rare events provide the opportunity for scientists to gather both new scientific observations and re-creations of historical ones.