Black holes are like the ultimate party: Once you're sucked in, you're never going to leave. Their sheer mass means nothing can escape, not even light — and blocking that out makes them very dark indeed. It turns out the block party isn't just happening in space, though. Scientists say the ocean has black holes of its own.
Let's dive into the astrophysics.
According to the laws of astrophysics, there is a point where matter ceases to spiral as it falls into a black hole and straightens up to enter an impenetrable circular orbit. Nothing can travel back out from the edge of these closed light orbits — Albert Einstein called them "photon spheres" — and re-emerge into space.
All matter, once captured by the gravitational field, is in there for good. Surely black holes don't hang out in the sea, though, right?
Well, using observations from satellites, scientists at the University of Miami and Switzerland's ETH Zurich have developed new ways of analyzing the movements of the huge swirling eddies of water — or maelstroms — that occur in the Southern Ocean. Mathematically speaking, they say, these Agulhas rings, near the tip of South Africa, actually bear close similarities to black holes.
So ... how big of an oceanic black hole are we talkin'?
The eddies are massive, churning areas of water as large as cities and containing billions of tons of water. The incredible size and strength of the maelstroms gives them their own specific and intense water flow pattern.
According to the scientists, it's a pattern very similar to that of light particles in a photon sphere. Each drop of water travels in a fierce loop, tracing back on itself to prevent any movement beyond the circle. This means the limits of the eddy are so tight, nothing can break out.
Because they seal in every drop of fluid, the maelstroms make perfect transportation devices for anything that gets trapped in them. Volumes of salt water, microorganisms and various other flotsam are pushed northwest by the migrating currents before they're eventually released as the eddy slowly loses its power in colder waters.
And the researchers say their satellite research could end up helping us with some very down-to-earth problems. The shifting patterns can help us look into the movement of manmade trash and oil spills, while gaining better insight into currents may even help slow down the melting of sea ice.