Transit of Mercury

space · planets · astronomy · solar system

Tiny wanderer crossing. During a transit of Mercury, the planet passes directly between Earth and the Sun, looking like a small black dot moving across the bright solar disk. It's like watching a cosmic game of peek-a-boo.

May or November timing. Mercury transits only happen in May or November because of how Mercury's orbit lines up with Earth's position. This happens about 13 or 14 times every 100 years, much more often than Venus transits do.

Hours-long event. A transit of Mercury takes several hours to complete as the planet slowly crawls across the Sun's face. Astronomers watch carefully with special telescopes to study Mercury and our Sun.

Speedy inner planet. Mercury orbits the Sun much faster and is much closer to it than Venus, which is why Mercury transits happen so much more frequently. Mercury races around the Sun while Venus takes its sweet time.

Rare observation moments. The last transit happened on November 11, 2019, and the next one won't occur until November 13, 2032, so astronomers and skywatchers have to wait years between these special events.