It’s a scene straight out of a horror movie — a submersible with five souls on board implodes, deep below the ocean’s surface, at the resting place of the infamous Titanic.

Many reporters are asking if there will be an attempt to bring up the bodies.

But what actually happens to the human body in such unfathomable depths? The answer lies in the peculiar, high-pressure, high-temperature world of deep-sea physics. Join me on a journey through time — millisecond by millisecond — to explore this dark, alien realm.

The Physics of Pressure

Before we take the plunge, let’s do a quick crash course on pressure. In everyday terms, pressure is force exerted on an area. In our normal environment, that’s air pressure. But as you descend under water, that pressure increases due to the weight of the water above. Roughly, for every 10 meters (33 feet) you descend, the pressure increases by 1 atmosphere (atm), or approximately 14.7 pounds per square inch (psi).

The Titanic wreckage lies at a depth of about 3,800 meters (12,500 feet). At that depth, the pressure is an astonishing 380 atmospheres, or about 5,600 psi. That’s equivalent to having a large elephant standing on every inch of your body.

Milliseconds of Terror

In our dreadful scenario, let’s assume the submersible wall failed suddenly and catastrophically. What would happen to the passengers within?

The First 10 Milliseconds

At the very moment the hull breaches, there’s an immediate equalization of pressure. The air inside the submersible, previously at a comfortable 1 atmosphere, must now contend with the 380 atmospheres outside.

The results are explosive. Literally.

Pascals are a unit of pressure. At this depth, the pressure on all sides of the air bubble containing these five men is 38,503,500 pascals. This is the same amount of pressure released by 292 kilograms of C4 explosive.

But this is just the start of our descent into the trauma abyss. The imploding bubble of the submersible generates intense heat due to adiabatic compression.

11–50 Milliseconds: Fiery Inferno Below the Waves

Adiabatic compression is a rapid, heat-generating compression process that occurs in gasses under extreme pressure.

As the submersible collapses, the quickly compressing pockets of gas inside it heat up rapidly, reaching temperatures that may exceed several thousand degrees Celsius for a brief moment.

The searing heat would vaporize flesh and bone, but this pales in comparison to the rapid pressure changes already wreaking havoc on the body. The passengers would already be dead due to the massive bodily trauma by the time the heat wave hits.

50 Ms to 1 Second: The Speed of Pain

A human’s reaction to pain depends on the transmission of signals from our peripheral nervous system to our brain. Once the signals reach the brain, we feel pain. This process is not instantaneous — it takes time.

Under normal conditions, a sensation of pain, such as from a stubbed toe or a pinch, reaches our brains about 0.1 seconds after the event. This is because the signals travel at a speed of about 2 meters per second along our nerves.

However, sharp, sudden pain can be perceived slightly faster, at around 0.01 seconds due to the involvement of faster-conducting nerves called A-delta fibers.

Comparing these timeframes to the catastrophic implosion event we’ve been discussing, the submersible’s complete collapse takes place in about 50 milliseconds (0.05 seconds). This means the implosion happens 2 to 10 times faster than the human body can register pain.

Given this, it’s probable that the occupants of the submersible would not have had time to even comprehend anything at all had happened, much less feel pain from the event itself.

The sequence of events — the crushing pressure, the searing heat of the compression of air, and the violent intrusion of water — would likely occur faster than the brain’s ability to process any thoughts.

That’s a cold, small comfort, perhaps, but it’s a detail that can help us cope with the death these five people experienced. Our brains, evolved to react to the world at the surface, simply don’t have the time to comprehend the immediate and extreme changes happening in those fateful 50 milliseconds beneath the waves.

From Tragedy, Knowledge

The sudden implosion of a submersible, while terrifying, provides a glimpse into the harsh realities of deep-sea exploration and the physics at play in these extreme environments.

The lessons learned from these tragic incidents are incorporated into writing regulations for manned submersibles, the design of future submersibles, making each new venture into the depths a little bit safer.

Through tragedy, we gain knowledge — knowledge that helps us better understand our world and how to navigate its dangers.

It’s a harsh lesson, a testament to the extremes the human body can — and cannot — endure. But it also shows us the immense power of nature, the fragility of life, and the courage of those who dare to push the boundaries of human exploration.

And with each dive, with each venture into the unknown, we’re reminded just how much there still is to discover.

In the end, the quest to understand our world — from the deepest oceans to the farthest stars — is a testament to human curiosity and resilience. It’s a journey filled with risks, challenges, and, sometimes, profound loss. But it’s through this journey that we learn, grow, and push the boundaries of what’s possible.