Most outbreaks have occurred in Africa, far from the Siberian lab where the senior technician was experimenting on guinea pigs when the accident happened on May 5. She died two weeks later.

Set deep in Siberia, a four-hour flight from Moscow, the state-owned Vector research center at Novosibirsk does research into deadly diseases such as SARS and anthrax.

Along with the U.S. Centers for Disease Control, it is one of only two places on earth with official stockpiles of smallpox, which killed around 300 million people last century.

After the accident, the woman was hospitalized in a ward specially equipped to contain virulent diseases. Anyone who came into contact with her was put under observation for three weeks.

So when Clark found the new generation of road sensor, Arnu drove out to help investigate further. The pair found that, at close range, they could use a handheld frequency counter to pick up the wireless signals given off by the devices as a car passes. Over the following month and half, Clark and Arnu engaged in a kind of geocaching game with the Men in Black, systematically sniffing out the road sensors with the frequency counter, exhuming them, and opening them up. They discovered that each device was coded with three-digit identifier that could be read off an internal dial, allowing Arnu to make a list that correlated each unit's ID number with its GPS coordinates, creating a virtual map of a portion of the surveillance network surrounding the Groom Lake facility. Some of the sensors were miles away from the base.

"We dug up about 30 or 40 of them on various access roads leading to the base on public land," Arnu says, insisting that he and Clark always carefully reburied each unit after logging it, and even tested it with the frequency counter to make sure it was still working before moving on to the next one.

Asimov's Foundation novels - the most famous science-fiction trilogy between Lord of the Rings and Star Wars - described a new science of social behavior called psychohistory. Mixing psychology with math, psychohistory hijacked the methods of physics to precisely predict the future course of human events.

Today, Asimov's vision is no longer wholly fiction. His psychohistory exists in a loose confederation of research enterprises seeking equations that capture patterns in human behavior. These enterprises go by different names and treat different aspects of the issue. But they all share a goal of better understanding the present in order to foresee the future, and possibly help shape it.

What makes the latest discovery, dubbed 2004 GU9, of great interest to astronomers is the remarkable stability of its orbit. It has remained a quasi-satellite of Earth for at least 600 years. Before this phase, the object traveled in a horseshoe-shaped orbit that astronomers have tracked back at least 50,000 years. According to Martin Connors of Athabasca University in Alberta, Canada, 2004 GU9 is the first object in its class to maintain a long stretch of orbital stability. Connors presented his team's study of the object at the 2004 Joint Assembly of the American and Canadian Geophysical Unions, held this week in Montreal, Canada.

-- Investigators found red streaks -- transfer marks, they call them -- on various pieces of the shredded Cessna pulled from the muck. The red does not match red mail bags or other objects known to be on the plane.

-- Investigators also found a small piece of black anodized aluminum embedded in the skin of Preziose's plane. The aluminum is not from the accident airplane.

Those facts led National Transportation Safety Board accident investigator Butch Wilson to conclude the Preziose's Cessna 208B Caravan "collided in-flight with an unknown object."

"There are very definitely strong emotional ties to the rovers," said Steve Squyres of Cornell University in Ithaca, New York, and principal investigator for the science payload carried on each of the rovers.

"We poured our hearts and souls into these things for years, so how wouldn't there be? In fact, for me personally, it was actually a little hard just to say goodbye to them at launch. It's going to be very hard to say goodbye to them forever," Squyres told SPACE.com.

As to how Squyres and his colleagues will deal with the eventual loss of the Mars machinery, he responded: "I don't know... ask me that when we get to that point. The sadness from losing the vehicles will be balanced, in part, by a big plus. We'll get our lives back! Flight operations have been exhausting, involving a lot of time away from our families. So, in that regard, life will certainly get easier after they're gone."