The Physics of a Stone in the Mariana Trench: Would It Sink to 11,000 Meters?

When contemplating throwing a stone from the surface of the ocean into the deepest part of the Earth's oceans, the Mariana Trench, several factors come into play. Here, we delve into the physics of such an experiment and address common misconceptions about the descent and eventual fate of the stone.

Would a Stone Sink to the Bottom of the Mariana Trench?

The simple answer is yes, a stone will sink to the bottom of the Mariana Trench. However, the process is not straightforward. Imagine dropping a rock from the surface of the ocean directly above the Challenger Deep, renowned for being the deepest known point on Earth at 10,984 meters (11,034 meters with uncertainty).

Decompression and Density

While the stone will indeed reach the bottom, its descent will slow gradually as it goes deeper. Water, though incompressible, does gain a slight density with increasing pressure. This means that the stone, which would be denser than the water at the surface, will experience less buoyant force as it descends.

Speed and Impact

Could the stone reach high speeds before hitting the ocean floor? Absolutely. Deep-sea diving vessels and submarines often experience intense pressure and damage upon impact with the abyssal depths. One estimate suggests the descent speed could be over 100 mph (160 km/h). This rapid descent and impact can cause significant deformation and even shattering of the object, similar to what happens to vessels that encounter the extreme pressure at such depths.

Current Considerations

The question does not need to involve a heavy stone. As long as the throwing point is over the deepest spot and the current is not powerful enough to push the stone away, yes, any solid object will eventually reach the bottom. Fluid dynamics play a crucial role in these situations. Oceans are not uniformly still; currents and turbulence can impact the descent of objects. However, if the conditions permit it, the stone will sink and eventually come to rest on the seafloor.

Examples and Analogies

For a real-world example, imagine dropping beer bottles or metal pie plates from a submersible like Alvin at a depth of 3,500 meters. These objects have been observed to sink rapidly until they come to rest on the seafloor. Submersibles themselves operate by adjusting their density, using weights and buoyancy to control their movement. When coming to the bottom, they jettison heavy weights to achieve neutral buoyancy and when ascending, they remove additional weights to become buoyant.

Conclusion

In conclusion, a stone, whether heavy or light, will indeed sink to the depths of the Mariana Trench. The process, marked by gradual slowing due to increased pressure and density, eventually culminates in the object impacting the seafloor. Understanding the physics behind this fascinating interaction helps us appreciate the unique conditions that exist in the world's deepest oceanic trenches.