Superhuman Senses

Accidentally Counting Fish

Nicholas Makris didn't set out to count fish. His original goal was to locate ancient riverbeds under the ocean floor.

But the team on which this MIT professor worked soon realized that the new sonar technique they were using allowed them to see enormous schools of fish. In fact, by using low frequency sound waves - which travel great distances - this method can study fish over an area a million times larger than previous techniques allowed.

Makris is the lead author of a new article in the journal Science. The article reports that researchers can now gain an accurate picture of fish over a 4,000 square mile area. Previous methods relied on snapshots of 120 square yard areas.

"It would be like watching 'Casablanca' and you're seeing one pixel moving across the screen, and that's all you get," explained Makris. "You can't figure out what's going on, it's way too slow."

The MIT team was surprised to discover one shoal of fish that was six to nine miles long.

This new method is important because it allows researchers to better understand fish populations, so that nations can balance the need to guard fish stocks while enabling commercial fleets to operate in a sustainable manner.

"The world's fish stocks are being depleted at a horrible rate," said Makris, "One of the reasons (for the inaccurate counts) is the darkness in the ocean. You don't know what's going on."

Co-authors on the paper are Purnima Ratilal (Ph.D. 2002) of Northeastern University; Deanelle Symonds, Srinivasan Jagannathan and Sunwoong Lee of MIT's Center for Ocean Engineering; and Redwood Nero of the Naval Research Laboratory.

Living with One Trillion Sensors

Can you imagine life on an Earth populated by one trillion sensors? That's about 167 sensors for every man, woman and child.

Look out your window. You did it.

Some analysts say we already have one trillion sensors on the planet. In a December 2004 meeting hosted by IBM, Henry Tirri from Nokia Research Center said that although we have only some 300 million PCs today, we have more than 1 billion information devices (such as mobile phones and PDAs); 2 billion "smart devices" in buildings, appliances, and vehicles; 500 billion microprocessors; and more than 1 trillion sensors and radio frequency identification devices.

But in a February 2004 report, IDC predicted we would have one trillion sensors by 2012.

As reported in a 1999 BusinessWeek article, Ernst & Young predicted that by 2010 - now just four years away - there would be 10,000 telemetric devices for every human being on the planet. If my math is correct, that would be three trillion sensors just in the United States, and 60 trillion worldwide.

In truth, no one has the faintest idea how many sensors already exist, or how fast they are proliferating. That's largely because there are so many different kinds of sensors, and because they are used in nearly every industry.

Some sensors support industrial processes while others facilitate environmental research. The span of current applications is huge; the span of potential applications is mind-boggling.

For example, in 2002 author Marcia McNutt speculated that by 2025 low-cost "drifters" will have been riding the ocean currents for decades, enabling us to predict the weather of the ocean. In fact, drifters are a reality today and data from these devices is even being integrated into elementary school classrooms.

No matter what industry or use you consider, it's easy to think of potential uses for sensors. If we are not already at the one trillion sensor mark, we will be there soon - and fly past it.