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How Tall Buildings Stop Themselves Rocking
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Why Americans Vote on Tuesdays
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The Circle Hiding in Every Rainbow
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Grab your coffee and let’s dive in.

Near the top of Taipei 101, a golden steel sphere the size of a small room hangs in open air where office workers and tourists can watch it. The tower rises 508 meters over Taipei, Taiwan, and after it opened at the end of 2004 it spent several years as the tallest building on Earth. The sphere is a tuned mass damper, a 660-metric-ton pendulum suspended between about the 87th and 92nd floors. Its quiet job is to keep the tower from swaying enough in a typhoon to make the people upstairs feel seasick.

A tall building has a natural rhythm, a preferred pace at which it wants to rock, the way a child on a swing gains height if each push arrives on time. Wind and distant earthquakes can feed that rhythm until the motion grows unpleasant or dangerous. Engineers answer with a heavy mass that is not bolted rigidly into the frame. In Taipei 101 the mass is a sphere about 5.5 meters across, welded from 41 layers of thick steel plate and hung from the 92nd floor on 92 steel cables, with eight hydraulic dampers around its base. When the tower drifts one way, the ball lags and pulls the other. The dampers turn that tug-of-war into heat. The system is tuned so the ball's swing fights the building's own sway instead of adding to it. Researchers who instrumented the tower measured a fundamental sway period of roughly six to seven seconds, which is the rhythm the damper is tuned to fight. It is designed to move up to about 1.5 meters, and during Typhoon Soudelor in August 2015, with winds near 160 kilometers an hour over Taipei, it swung about a meter, the farthest on record for that damper.

The device was designed by the Canadian firm Motioneering and built by A+H Custom, with two smaller dampers tucked into the spire. Other skyscrapers hide similar weights in ceilings and mechanical floors, sliding blocks or pendulums that tenants never see. Taipei 101 put its main damper in the sightseeing path on purpose, and a machine invented to quiet a tower became one of the building's main attractions. Taiwan sits in typhoon paths and on shaking ground, and a tower that feels like a boat is hard to lease, so comfort is the everyday reason the ball is there. The golden ball does not make the building immovable, and studies of the tower find it far more helpful against wind-driven sway than against every kind of distant earthquake. It steals just enough energy from each sway that the upper floors stay usable while the storm does its worst outside.

Every even-numbered year, millions of Americans squeeze voting into a workday, lining up before dawn or racing to the polls after quitting time. In 1845 Congress fixed a single day for choosing presidential electors: the Tuesday after the first Monday in November. The first presidential election held under that rule fell on November 7, 1848. House debates at the time stressed a blunt worry: states had been free to appoint electors across a window of weeks, and as roads and newspapers improved, later-voting states could hear early results and tilt accordingly. By 1845 every state but South Carolina was already choosing electors by popular vote, so the shared calendar mattered more each cycle. One shared Tuesday was meant to cut the early-results game short.

Tuesday in early November was a farm calendar compromise. Most of the country still lived by harvest and frost. Late autumn came after the crops were in and before winter roads turned ugly, so rural voters could reach the county seat without abandoning the fields or fighting a blizzard. Travel often meant an overnight trip by horse on rough roads. Lawmakers did not want people riding on Sunday, the usual day of rest and worship, which made Monday a bad polling day because the journey would have begun the morning before. Wednesday was widely treated as market day, when farmers hauled goods into town. Tuesday sat in the gap. Choosing the Tuesday after the first Monday also kept Election Day off November 1, All Saints' Day for Catholics and the day many merchants settled the previous month's books.

In 1875 Congress put House elections on the same Tuesday, and after the Seventeenth Amendment made senators popularly elected, the 1914 Senate races followed that calendar too. Presidential, House, and Senate contests have shared the date ever since. The schedule outlived the farm world that built it. Pew Research has found that most other advanced democracies hold national elections on weekends, or turn a weekday vote into a holiday so work is not the price of a ballot; in one Pew count, 27 of 36 did so. American reformers have proposed weekend voting or a federal Election Day holiday for years, with wide public support in surveys, yet the 1845 Tuesday still stands for federal races. Thirteen states give at least some public workers the day off, and many employers now offer paid time to vote. Early voting and mail ballots have softened the Tuesday crush for millions of people, but the national Election Day on the calendar is still that midweek date chosen for wagons, harvests, and church bells. The line at the polling place follows a map drawn for an agrarian republic.