Most people assume that modern communication and the internet rely on satellites orbiting Earth, but the truth is, the backbone of global communication is far less flashy—and lies deep beneath the ocean’s surface. There are approximately 900,000 miles of submarine cables crisscrossing the seabed, connecting continents and carrying around 99% of international data. These cables, often no thicker than a garden hose, are responsible for transmitting our emails, phone calls, financial transactions, and even Netflix streams across the globe.

The Lifeline of Global Communication

Submarine cables are not a recent invention. In fact, the first successful undersea telegraph cable was laid across the Atlantic Ocean in 1858. Since then, technology has advanced significantly, allowing the internet to span the globe, powered by these intricate cable systems. Today, there are over 400 active submarine cables, some stretching thousands of miles, running along the ocean floor, silently transmitting data at the speed of light via fiber optics.

How Do These Cables Work?

These cables are composed of fiber optic strands that use light signals to transmit vast amounts of data quickly and efficiently. Each fiber is capable of carrying terabits of data per second. Surrounding the fibers are layers of protective materials to withstand underwater pressure, environmental conditions, and even the threat of fishing nets or anchors that could accidentally damage them.

Laying the cables is a massive engineering feat. Specialized ships, known as cable-laying vessels, deploy these cables from coastlines across deep oceans. These vessels use sophisticated equipment to ensure the cables are laid in a way that minimizes disruption to the ocean floor while avoiding underwater obstacles, such as trenches and mountain ranges.

Why Not Satellites?

While satellites are crucial for certain applications like weather monitoring and GPS, they aren’t nearly as efficient as submarine cables when it comes to transmitting large volumes of data. Undersea cables offer lower latency, meaning data travels faster between points, and they can handle the enormous data flow required by today’s interconnected world. Satellites simply can’t compete with the speed, reliability, and capacity of submarine cables.

For example, a satellite transmission might take 550 milliseconds to send a signal from New York to London, while a signal sent via an undersea cable takes around 60 milliseconds—a huge difference when it comes to tasks like high-frequency trading or video conferencing.

Challenges Facing Undersea Cables

Despite their crucial role in global communication, undersea cables are not invincible. They face several threats, both natural and man-made:

1. Damage from Anchors and Fishing Gear: Ships dragging their anchors or fishing nets across the seabed can accidentally rupture these cables, leading to temporary outages or reduced internet speeds in affected areas.

2. Sharks and Other Marine Life: There have been incidents where sharks have been seen biting undersea cables, likely attracted to the electromagnetic fields emitted by them. While this is rare, it’s a fascinating example of how nature can interact with human technology.

3. Natural Disasters: Earthquakes, underwater landslides, and tsunamis can also damage undersea cables, disrupting global communication networks.

4. Security and Sabotage: With global reliance on these cables, they have become critical infrastructure, which could make them potential targets for sabotage. Governments and private companies invest heavily in monitoring and protecting the security of undersea cables to prevent any tampering.

The Future of Submarine Cables

As the world becomes increasingly digital, the demand for high-speed internet and seamless communication continues to grow. Tech giants like Google, Facebook, and Amazon have recognized this and are investing heavily in undersea cables to ensure they have the capacity to support their global operations.

For instance, Google has funded multiple submarine cable projects, including the Equiano cable connecting Europe and Africa and the Dunant cable connecting the U.S. and France. These cables are designed to support the increasing demand for data, ensuring that the internet remains fast and reliable as more people and devices come online.

The Unsung Heroes of Connectivity

While we often take the internet and global communication for granted, it’s important to remember that these modern conveniences rely on a vast, hidden network of cables under the ocean. Spanning more than 900,000 miles, submarine cables are the unsung heroes of the digital age, allowing us to stay connected across continents.

As the world continues to rely on data for everything from banking to entertainment, these undersea cables will remain essential infrastructure, quietly powering the internet that brings us all closer together. So the next time you send an email or stream a video, remember that your data is traveling thousands of miles under the sea, thanks to a network of cables you may never see, but certainly rely on.