How much don’t we know?
Giant pairs of whirlpools travel across the ocean for months in a bizarre pair.
These large paired whirlpools, hundreds of kilometers across, travel eastward at something like 10-20cm per second. This is one pair crossing from Tasmania to NewZealand. This was there in our satellite data but “invisible” til recently. As David Evans says “I wonder what else we are observing but not seeing?”
In the mini-pool version, these rolling whirlpools are connected in a U shape under water.
Wow. PhysicsGirl shows how to make these by pushing a plate through the water, and adding food coloring. Switch on your science nerd, show the kids! (send me your photos :- ))
Twin giant ocean whirlpools travel for months winding their way across oceans
Peter Dockrill reports on an interview published in Popular Science
For the first time, scientists have recorded a bizarre phenomenon in fluid dynamics, which up until now had only ever been theoretically predicted, but never observed in the wild.
“Ocean eddies almost always head to the west, but by pairing up they can move to the east and travel ten times as fast as a normal eddy, so they carry water in unusual directions across the ocean,” explains oceanographer Chris Hughes from the University of Liverpool in the UK.
“What we found was a pair of eddies spinning in opposite directions and linked to each other so that they travel together all the way across the Tasman Sea, taking six months to do it.”
Since 1993, satellites have recorded nine of these pairs (called Modons). Eight of nine that have been found were around Australia. (Perhaps Australian-NZ oceanography is special, but I suspect other modons just haven’t been identified yet). From the paper:
h/t to David E
Watch Physics Girl do some extremely cool pool tricks.
I’ve seen 99% of the hands-on science tricks out there but this was totally new to me. Oogle away. The twin vortices leave pairs of shadows on the pool floor. They travel right across the pool, but vanish sometimes unpredictably, or are destroyed easily by any interference.
Notice the red ink whirlpool reaches over and envelops the blue one. The colors stay separate.
You can think of an ocean eddy as something like an underwater tornado with two ends. The swirling water is sped along the twisting vortex, pushing it from one spot in the ocean to another. They’re a well documented natural phenomenon, and serve to regulate temperatures and transport nutrients over large distances, but fast-moving twin eddies put a new spin on what scientists thought they already knew.
Researchers were able to observe the odd ocean behavior using satellite data to measure the depth at which the eddies took shape as well as the speed of the water within them. The flowing water acts like a two-lane highway, moving in both directions simultaneously.
For any small sea creatures not capable of escaping the vortex, the ride can be a long one.
We’re not sure how they are formed. From the paper:
Never too old to get excited. :- )