SINCE THEIR INCEPTION OF THE LEAP SECOND 50 years ago, 27 have been added to our clocks to make sure Universal Coordinated Time aligns with our solar reality-sort of like how leap days or leap years keep our calendars from becoming a complete chronological mess.
Well, no more. Last year, government representatives at the General Conference on Weights and Measures decided to scrap the leap second, beginning in 2035 and lasting until at least 2135 (or until we discover a better method for adjusting our clocks).
What Is a Leap Second? // Human time has long been calculated by how long it takes Earth to complete a full rotation on its axis. However, there's just one problemEarth doesn't rotate at a uniform rate. Earthquakes, volcanoes, tidal forces, and even wind patterns can affect how fast or how slow the world turns.
This is a problem because the world is built on the extreme timekeeping precision of atomic clocks, baked into the programming of orbiting satellites, financial markets, and everything in between. Atomic clocks calculate a second as "9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom," and cesium atoms don't know (or care) how fast Earth spins. Over time, these discrepancies can sometimes be more than a millisecond per day. When those milliseconds add up, the world needs to add another second.
This story is from the March - April 2023 edition of Popular Mechanics US.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 8,500+ magazines and newspapers.
Already a subscriber ? Sign In
This story is from the March - April 2023 edition of Popular Mechanics US.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 8,500+ magazines and newspapers.
Already a subscriber? Sign In
The Cascading Failures Behind One of the Worst Building Collapses in U.S. History
Engineers are still investigating the collapse of Champlain Towers South in Surfside Florida, but early findings shed light on a risk facing poorly constructed residential and office buildings,
Cutting the Cord
THE HANDHELD CIRCULAR SAW IS PERHAPS THE MOST VERSAtile power tool for cutting wood.
How Three Amateurs Solved the Zodiac Killer's '340' Cipher
The mysterious code stumped the FBI and NSA for 53 years. What does the key, and the resulting solution, tell us about the infamous murderer?
POPULAR MECHANICS TOP AWARDS 2024
For more than 120 years, Popular Mechanics has been a heavy-duty brand. We see no reason to change that now.
How This Particle Could Break Our Understanding of Reality
EINSTEIN'S SPECIAL THEORY OF relativity teaches us that nothing can accelerate past the speed of light. But what if, when you were born, you were already moving faster than light? What would that look like?
The Right Way to Use a Fire Extinguisher
A FIRE EXTINGUISHER IS MORE THAN A of one 5-gallon bucket becomes the size of 64 burning buckets. Just 180 seconds after it begins, a fire can be transformed from a nuisance to a room-size, life-threatening inferno.
How the World's Largest Spherical Structure Was Built
THE SHINY, NEW LAS VEGAS SPHERE IS more than just a 17,600-seat amphitheaterstyle venue hosting a U2 residency. Since its opening in September 2023, it's become the world's largest spherical structure, at 516 feet wide and 366 feet tall.
The Army's Drone-Killing Laser Weapon
THE U.S. ARMY FIELDED ITS FIRST LASERweapon-equipped unit in October. Based at Fort Sill, Oklahoma, the unit took possession of four laser-equipped Stryker infantry combat vehicles, each mounting a 50-kilowatt-class laser-weapon system. The combination of Stryker and laser can down both artillery, such as mortars and rockets, and drones in-flight.
Why It's So Hard to Mine the World's Largest Lithium Deposit
A Pass, or Peehee Mu'huh to the local Paiute people has been mined since the 1970s, so the new analysis merely confirms what locals have long known about the area.
WHAT THE WORLD'S MOST POWERFUL X-RAY LASER WILL DO FOR SCIENCE
DEEP UNDER MENLO PARK, California, there is a threemile-long machine operating in a tunnel that scientists are keeping colder than even some of the deepest reaches of space.
