The $250 million space experiment last week, meant to pave the way for anti-missile sensors that would track thousands of enemy targets, clearly showed the West's edge.

There are now only 2,000 immigration enforcement agents nationwide, and they have an array of duties that include tracking hundreds of thousands of visa violators.

This is important in some applications, but the computational resources needed to track thousands of cars, and the spatial relationships between them, quickly get expensive.

We're tracking hundreds of thousands of objects up there, anything from discarded solar panels to composite bolts.

The latest study, which appeared in the April 1 issue of The New England Journal of Medicine, tracked thousands of patients in Iceland over several decades.

An earlier study in Alameda County, Calif., that tracked thousands of people over a nine-year period showed that those with many social ties, like a spouse and friends, had significantly lower death rates.

One person using a broadband-enabled computer can track thousands of the tags, expected to cost less than $25 each.

To be clear, our mission is to protect the civilian population in Libya, not to track and target thousands of fleeing former regime leaders, mercenaries, military commanders and internally displaced people.

It requires sophisticated software capable of tracking hundreds of thousands of people.

Alex had tracked thousands of them with the big radio antenna.