Dolphin Whistles Help Solve The Mysteries Of The Cosmos

November 21, 2011 - via Fast Company

With a lot of help from Flipper, scientists have a better shot at understanding phenomena like black holes and supernovae.

Let's back up. To understand the connection between dolphins and supernovae, you have to start in the year 2000, when German company EvoLogics was founded. EvoLogics is one of the only firms on the planet whose entire output consists of biomimetic innovation. Its products and proofs-of-concept include robotic manta rays and penguins, ultra-efficient propellers and Terminator-like human torsos.

But the company's most successful innovation has been a system for allowing electronics to communicate at a distance under water. Acoustic modems--which use sound waves to transmit information--are one of the few viable methods for "wireless" communication in a medium that blocks or absorbs the electromagnetic waves we usually use.

Water transmits sound quickly, but it's also a noisy medium, full of countless other objects transmitting vibrations over vast distances. But dolphins have found a solution. Their distinctive whistles can be heard from as far away as 25 kilometers. Being heard above the din of the ocean without generating tremendously powerful calls can only be accomplished by sending your signal over as many different "channels" as possible.

In any medium, a wave traveling to a distant source may travel along many different paths, because it's traveling through different mediums and bouncing off things along the way. This means multiple copies of the same signal can arrive at its destination at slightly different times. Signals that arrive in this way can mess with the original message, as the two versions of the signal collide. It's called multipath interference, and if you've ever seen ghosting on old-style analog televisions, you've seen its effects.

Dolphins get around this kind of interference by continuously varying the frequency of their signal--in other words, by constantly adjusting the pitch of their call. By spreading it across many different frequencies, they increase the probability that at least part of the signal will arrive intact, no matter the conditions in the ocean.
It took eight years of research to determine exactly how dolphins do this, and the results were then poured into what is arguably the most advanced acoustic modem ever created. The results are a modem that misdelivers only one in every billion bits of information (PDF).

Evologics S2C modem has been on the market for a few years, and like all new technologies its taken that long for engineers to figure out what it might uniquely enable. Currently, it's in everything from deep-sea observatories to tsunami alert systems, but one of its most unique applications is in the Baikal Deep Underwater Neutrino Telescope.

Neutrinos are elementary particles that are born in stars and black holes and the Big Bang, and understanding them is vitally important to our understanding of the galaxy (currently, they're the partical that might be moving faster than the speed of light). The problem with neutrinos, though, is that they don't interact with matter very often. So, to find and study them, you need to be looking very carefully in a very controlled space.

The Russian Lake Baikal is one of those places. It's the deepest lake in the world. It's also the oldest--30 million years in the making--and every winter it freezes over with ice a meter thick. That makes it the perfect platform for a neutrino detector, which is lowered into its depths every February. For a neutrino detector to be sufficiently sensitive to be of much use, it needs to be inside at least a cubic kilometer of water. The world's largest of these type of detectors is buried deep in the South Pole. Building a comparable detector in Lake Baikal requires knowing exactly precisely where, in that one kilometer cube each of your neutrino sensors are.

That's where the dolphin modem comes in. A revamped Baikal neutrino detector requires that scientists know where their detectors are to within 40 centimeters. The S2C system--with a lot of help from dolphins--can position them to within 5 millimeters.

And that's how millions of years of cetacean evolution yielded a system that can peer into the deepest reaches of time and space.

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Author:Christopher Mims