⏱ Why Does One Second REALLY Matter?

One second might not seem like much. You blink and it’s gone.But in the world of science, space, GPS, and even banking — a single second can make a massive difference.

In this episode of The Curious Professors, we’re diving into the mysterious world of time: how we measure it, who decides it, and why the tiniest changes can affect the entire planet.

Welcome to the story of the leap second — and the ticking science behind our global clocks.

🧠 What Is a Leap Second?

Most of us think of time as exact — 60 seconds in a minute, 60 minutes in an hour, and so on. But here’s the thing: Earth doesn’t always follow the rules. Our planet’s rotation speeds up and slows down by tiny amounts. That means some days are a little shorter… or a little longer.

To keep our official time in sync with Earth’s time, scientists sometimes add a leap second — an extra second added to the clock. It usually happens at midnight on December 31 or June 30. Sounds simple, right? Well, it gets complicated fast.

🛰 Atomic Time vs. Earth Time

So who’s keeping track of all this?

Meet the International Earth Rotation and Reference Systems Service (IERS). Their job is to compare atomic time — the super steady time kept by vibrating cesium atoms — with Earth’s actual rotation.If Earth is running a little fast or slow, the IERS recommends a leap second to realign everything. Atomic clocks are so precise, they don’t miss a beat for millions of years.But Earth? She’s a little more unpredictable.

➕ Or… Subtract a Second?

Until now, all leap seconds have been added.But scientists now believe Earth is spinning faster. That means we might need to do something we’ve never done before — subtract a second.

It would be called a negative leap second. Instead of adding time at midnight, we’d skip a second entirely. One second would simply vanish — poof — like it was never there.

🌍 Why Does It Matter?

Think it doesn’t affect you? Think again.

Systems like GPS, air traffic control, the internet, and banking all rely on exact timing.If two systems are out of sync by even one second, it can cause big problems — from navigation errors to financial glitches.

For example: If GPS satellites are off by a single millisecond, your location could be wrong by several miles. In banking, a 1-second difference could mean a payment goes through before or after a stock price changes — which is a big deal for computers that trade billions in seconds.

🕰 A Global Decision

In 2022, world leaders and scientists voted to phase out leap seconds entirely — starting in 2035.Why? Because they cause more trouble than they solve. Instead, they’ll let atomic time and Earth time slowly drift apart — and find better ways to adjust over longer periods. It’s a big shift in how humans think about time… and it shows that even seconds are decided by cooperation.

🎧 Want More?

This blog post is based on our podcast episode:🎙 Why Does One Second REALLY Matter?, featuring Professor Punzworth, Professor Sagewell, Sunny Crisp, and Archivist Alex.

Together, they explore the science of timekeeping, the politics of leap seconds, and how our entire world runs on precision.

🕐 Leap Second Fast Facts

📏 Leap seconds help align atomic time with Earth time

⏳ Earth’s spin can change speed slightly — making days longer or shorter

🌐 Systems like GPS, banking, and the internet depend on perfect timing

➖ A negative leap second has never happened… but it might

🗓️ Leap seconds are usually added on December 31 or June 30

💬 Discussion Question

If you could change how the world keeps time, what would you do?Would you add a leap minute? Skip Mondays? Replace time zones with just one global clock?Let us know in the comments!