Chicagohenge: A Modern Urban Phenomenon with Ancient Roots
Each year, the fall equinox heralds the start of shorter days and shifts in seasons, but it also brings a unique celestial dance in urban settings. As the sun rises and sets, its alignment with east-west city streets offers a spectacular view reminiscent of ancient astronomical observances. This alignment is similar to the well-known phenomenon observed at Stonehenge.
Geoff Boeing, chair of the Department of Urban Planning and Spatial Analysis at the University of Southern California, explains, “Humans still connect with how special it feels,” emphasizing the intersection of urban development and celestial events.
The Chicagohenge Effect
Chicago, with its grid-like street design, is a prime location to witness this event, aptly named “Chicagohenge.” Michelle Nichols, senior director of public programs at the Adler Planetarium, describes the scene: “In Chicago’s canyon of tall buildings, especially in the downtown area, the sun will be framed by the rising sun, and the setting sun will be framed by those tall buildings.” This effect is most visible on wide streets running east and west.
The event is not exclusive to Chicago. Cities like Washington, D.C. and Phoenix also offer opportunities to experience similar alignments.
A Glimpse into History
The fascination with celestial alignments is not new. Boeing notes, “It’s interesting because this is a very old phenomenon.” Historical cities like Tenochtitlan were designed with astronomical precision, as noted in a 2021 academic paper.
Today, the alignment of city streets with celestial events is more coincidental than intentional. Nevertheless, Boeing remarks, “Even if we didn’t do it intentionally, we’re still getting the same side effects at least once or twice a year.”
Spotting a “Henge” in Your City
Cities like Chicago and Denver, as noted in Boeing’s analysis of cities’ street grids, are particularly suited for witnessing equinox alignments due to their adherence to compass-based grids. These grids facilitated land transactions and infrastructure mapping during America’s 19th-century expansion.
However, non-compass-aligned cities like New York’s “Manhattanhenge” and San Francisco’s “California Henge” offer unique celestial views not bound to the equinox.
Capturing the Moment Safely
With the rise of social media, capturing these celestial alignments has become popular, especially during the pandemic when shared experiences were rare. Nichols advises, “Don’t walk out in the middle of the street to be able to take the perfect photo. You can do this from the sidewalks, on the side. It’s totally fine.”
Driving during these alignments requires caution due to potential sun glare, which can obscure vision and increase traffic risks. As Nichols notes, “You do see traffic buildups and backups because of the location of the sun in the sky.”
This article was originally written by www.npr.org
