America's oldest planetarium
When it first flicked on the projector lights in 1930, the Adler Planetarium in Chicago was the only one in the Western Hemisphere. At the time, planetariums themselves were only a 7-year-old invention imported from German lens grinders. But the American public's fascination with stars and distant worlds, it turned out, was skyrocketing. By 1934, the Adler had welcomed over a million visitors.
And though our love for space endures, these days in Chicagoland it's tough to catch a clear night sky past all those wonderful bright lights of the Windy City. That helps explain why the Adler still pulls half a million visitors in a typical year, with three state-of-the-art auditoriums and even a massive telescope that lets visitors view far-off galaxies.
If the first day of daylight saving time doesn't have you springing for joy, this towering timekeeper might be more your speed. The astronomical clock at Lyon Cathedral in France was built in 1660, long before daylight time became widely adopted in the 20th century. The clock's intersecting hands and dials don't just tell time, they form a flattened model of our planet that tracks the positions of the sun and moon relative to Earth. The zodiac dial, offset to account for the planet's rotational tilt, shows the star sign currently in season.
All this movement of circles and spheres might call to mind another observance of the day: March 14 is Pi Day, in celebration of the mathematical constant pi (aka π, or roughly 3.14). You remember pi from geometry class: It expresses the ratio of the distance around a circle to the distance across it. So it was essential to ancient astronomers who mapped these celestial workings, as well as to designers of intricate machines that simulate the circling heavens.
Wow, you kept reading through all the math talk? You deserve a sweet payoff. Why not slice into our Pi Day pie quiz?