Watch The Mercury Transit Across The Sun VIDEO

For more than seven hours on Monday, Mercury will appear as a black dot on the face of the sun in an event that happens only about 13 times per century. For the first time in 10 years, Earth-dwellers can watch the planetary event, which started at about 7 a.m. ET. Astronomers caution that those watching should only view the event through protective solar filters on binoculars or telescopes; it’s also available on several live streams.