Four-thousand years ago, early Europeans’ connected with the Cosmos every Summer Solstice by watching the midsummer sunrise directly over the Heel Stone in what we now call Stonehenge. These early people recognized that where the sun rises and sets on the horizon cycles North and South with the seasons. Today, thousands of people gather four times a year for a similar event along the streets of downtown Manhattan. Coined as a portmanteau of the island name and the ancient architecture, Manhattanhenge describes the four days a year when the setting or rising Sun aligns perfectly with the gridding of North America’s largest city.
Manhattan’s avenues are rotated approximately 29 degrees from true North-South, so the streets are rotated 29 degrees clockwise from true East-West. At 40 degrees North of the equator, the Sun in NYC rises and sets farther South during the winter and rises and sets farther North during the summer. Between these two extremes, the rise and set positions slowly march their way across the horizon, slowly coming to a stop and changing direction each summer and winter. Twice a year, once while nearing the Summer Solstice, and again soon after it, the Sun reaches far enough North by sunset to peer down the Big Apple’s gridded streets. Because the sunset and sunrise locations are approximately mirrored from East to West, two similar days straddle the Winter Solstice, during which the rising sun appears between the city’s towering building.
Astrophysicist Neil deGrasse Tyson popularized Manhattanhenge as an opportunity for city dwellers to connect with space, but Manhattanhenge is not the only serendipitous alignment between the Sun and our infrastructure. Similar phenomenon such as Chicagohenge, Torontohenge, Montrealhenge, and MIThenge occur whenever an approximately East-West corridor lines up with the rising or setting Sun. So next time the Sun is in your eyes on the way to work, you can cheer yourself up with a new name, maybe follow the tradition by enjoying your newly discovered “driving-to-work-henge.”