Tue December 17, 2013
Dr. Francisco Beron-Vera, University of Miami - Black Holes of the Sea
In today’s Academic Minute, Dr. Francisco Beron-Vera discusses vortices that transport bodies of water around the globe.
Francisco Beron-Vera is a research associate professor in the Rosenstiel School of Marine and Atmospheric Science at the University of Miami. He research interests include the transport and mixing processes in geophysical fluids as well as geophysical fluid dynamics and thermodynamics.
Dr. Francisco Beron-Vera - Black Holes of the Sea
The ocean is filled with eddies, swirling water bodies that travel across basins.
Some eddies can be very large, of over 150 kilometres in diameter, and play an
important role in climate. An example are eddies shed from the Agulhas Current
at the southern tip of Africa, which are believed to carry out the Indian-to-Atlantic-
Ocean transport of warm and salty water. It is speculated that this transport, which
is reportedly on the rise, can have a moderating effect on melting sea ice in a
So far, oceanographers have been unable to quantify this effect, because the
exact boundaries of the eddies have remained undetectable. In collaboration with
Professor George Haller, from ETH Z¨urich, we recently developed a mathematical
technique to find water-carrying eddies with coherent boundaries, providing
a solution to this problem. To our surprise, such coherent eddies turned out to be
mathematically equivalent to black holes.
Black holes are objects in space with a mass so large that they attract everything
that comes within a certain distance of them. Nothing that comes too close
can escape, not even light. But at a critical distance, a light beam no longer spirals
into the black hole. Rather, it bends and comes back to its original position,
forming a circular orbit or barrier, so-called photon sphere.
Our technique detects eddies with similar closed barriers around. In these
barriers, fluid particles move around in closed loops, like light in a photon sphere.
And as in a black hole, nothing can escape from the inside of these loops, not even
We discovered Agulhas Current eddies of the black-hole type transporting the
same body of water without leaking for over a year. We expect that our results
help in answering many questions relating to the role of these eddies in climate.