Mobiles are barred, but passengers can lap away on their laptops to their hearts’ content. Is one really safer than the other? In the US, a Congressional subcommittee grilled airline representatives and regulators about the issue last month. But the committee heard that using cellphones in planes may indeed pose a risk albeit a slight one. This would seem to vindicate the treatment of Manchester oil worker Neil Whitehouse, who was sentenced last summer to a year in jail by a British court for refusing to turn off his mobile phone on a flight home from Madrid. Although he was only typing a message to be sent on landing not actually making a call, the court decided that hems putting the flight at risk.

A The potential for problems is certainly there. Modern airliners are packed with electronic devices that control the plane and handle navigation and communications. Each has to meet stringent safeguards to make sure it doesn’t emit radiation that would interfere with other devices in the plane-standards that passengers’ personal electronic devices don’t necessarily meet. Emissions from inside the plane could also interfere with sensitive antennae on the fixed exterior.

B But despite running a number of studies, Boeing, Airbus and various government agencies haven’t been able to find clear evidence of problems caused by personal electronic devices, including mobile phones. “We’ve done our own studies. We’ve found cellphones actually have no impact on the navigation system,” says Maryanne Greczyn, a spokeswoman for Airbus Industries of North America in Herndon, Virginia, Not do they affect other critical systems, she says The only impact Airbus found? “Sometimes when a passenger is starting or finishing a phone call, the pilot hears a wry slight beep in the headset,” she says.

C The best evidence yet of a problem comes from a report released this year by Britain’s Civil Aviation Authority. Its researchers generated simulated cellphone transmissions inside two Boeing aircraft. They concluded that the transmissions could create signals at a power and frequency that would not affect the latest equipment, but exceeded the safety threshold established in 1984 and might, therefore, affect some of the older equipment on board. This doesn’t mean “mission critical” equipment such as the navigation system and flight controls. But the devices that could be affected, such as smoke detectors and fuel level indicators, could still create serious problems for the flight crew if they malfunction.

D Many planes still use equipment certified to the older standards, says Dan Hawkes, head of avionics at the CAA’s Safely Regulation Croup. The CAA study doesn’t prove the equipment will actually fail when subjected to the signals but does show there’s a danger. “We’ve taken some of the uncertainty out of these beliefs,” he says Another study later this year will see if the cellphone signals actually cause devices to fail.

E In 1996, RTCA, a consultant hired by the Federal Aviation Administration in the US to conduct tests, determined that potential problems from personal electronic devices were “low”. Nevertheless, it recommended a ban on their use during “critical” periods of flight, such as take-off and landing. RTCA didn’t actually test cellphones, but nevertheless recommended their wholesale ban on flights, But if “better safe than sorry” is the current policy, it’s applied inconsistently, according to Marshall Cross, the chairman of Mega Wave Corporation, based in Boylston, Massachusetts. Why are cellphones outlawed when no one considers a ban on laptops? “It’s like most things in life. The reason is a little bit technical, a little bit economic and a little bit political,” says Cross.

F The company wrote a report for the FAA in 1998 saying it is possible to build an on-board system that can detect dangerous signals from electronic devices. But Cross’s personal conclusion is that mobile phones aren’t the real threat. “You’d have to stretch things pretty far to figure out how a cellphone could interfere with a plane’s systems,” he says. Cellphones transmit in ranges of around 400, 800 or 1800 megahertz. Since no important piece of aircraft equipment operates at those frequencies, the possibility of interference is very low, Cross says. The use of Computers and electronic game systems is much more worrying, lie says. They can generate very strong signals at frequencies that could interfere with plane electronics, especially if a mouse is attached {the wire operates as an antenna or if their built-in shielding is somehow damaged. Some airlines are even planning to put sockets for laptops in seatbacks.

G There’s fairly convincing anecdotal evidence that some personal electronic devices have interfered with systems. Aircrew on one flight found that the autopilot was being disconnected, and narrowed the problem down to a passenger’s portable computer. They could actually watch the autopilot disconnect when they switched the computer on. Boeing bought the computer, took it to the airline’s labs and even tested it on an empty flight. But as with every other reported instance of interference, technicians were unable to replicate the problem.

H Some engineers, however, such as Bruce Donham of Boeing, say that common sense suggests phones are more risky than laptops. “A device capable of producing a strong emission is not as safe as a device which does not have any intentional emission,” lie says. Nevertheless, many experts think it’s illogical that cellphones are prohibited when computers aren’t. Besides, the problem is more complicated than simply looking at power and frequency. In the air, the plane operates in a soup of electronic emissions, created by its own electronics and by ground-based radiation. Electronic devices in the cabin-especially those emitting a strong signal-can behave unpredictably, reinforcing other signals, for instance, or creating unforeseen harmonics that disrupt systems.

I Despite the Congressional subcommittee hearings last month, no one seems to be working seriously on a technical solution that would allow passengers to use their phones. That’s mostly because no one -besides cellphone users themselves-stands to gain a lot if the phones are allowed in the air. Even the cellphone companies don’t want it. They are concerned that airborne signals could cause problems by flooding a number of the networks’ base stations at once with the same signal This effect, called bigfooting, happens because airborne cellphone signals tend to go to many base stations at once, unlike land calls which usually go to just one or two stations. In the US, even if FAA regulations didn’t prohibit cellphones in the air, Federal Communications Commission regulations would.

J Possible solutions might be to enhance airliners’ electronic insulation or to fit detectors which warned flight staff when passenger devices were emitting dangerous signals. But Cross complains that neither the FAA, the airlines nor the manufacturers are showing much interest in developing these. So despite Congressional suspicions and the occasional irritated (or jailed) mobile user, the industry’s “better safe than sorry” policy on mobile phones seems likely to continue. In the absence of firm evidence that the international airline industry is engaged in a vast conspiracy to overcharge its customers, a delayed phone call seems a small price to pay for even the tiniest reduction in the chances of a Plane Crash. But you’ll still be allowed to use your personal computer during a flight. And while that remains the case, airlines can hardly claim that logic has prevailed.

 On October 13,2,000, a small team of paleontologists led by Paul Sereno of the University of Chicago clambered out of three battered Land Rovers, filled their water bottles, and scattered on foot across the toffee-colored sands of the Tenere desert in northern Niger. The Tenere , on the southern flank of the Sahara, easily ranks among the most desolate landscapes on Earth. The Tuareg , turbaned nomads who for centuries have ruled this barren realm, refer to it as a “desert within a desert”-a California-size ocean of sand and rock, where a single massive dune might stretch a hundred miles, and the combination of 120-degree heat and inexorable winds can wick the water from a human body in less than a day. The harsh conditions, combined with intermittent conflict between the Tuareg and the Niger government, have kept the region largely unexplored.

 Mike Hettwer, a photographer accompanying the team, headed off by himself toward a trio of small dunes. He crested the first slope and stared in amazement. The dunes were spilling over with bones. He took a few shots with his digital camera and hurried back to the Land Rovers. “I found some bones:’ Hettwer said, when the team had regrouped. “But they’re not dinosaurs. They’re human.”

 In the spring of 2005 Sereno contacted Elena Garcea, an archaeologist at the University of Cassino, in Italy, inviting her to accompany him on a return to the site. Garcea had spent three decades working digs along the Nile in Sudan and in the mountains of the Libyan Desert, and was well acquainted with the ancient peoples of the Sahara. But she had never heard of Paul Sereno. His claim to have found so many skeletons in one place seemed far fetched, given that no other Neolithic cemetery contained more than a dozen or so. Some archaeologists would later be skeptical; one sniped that he was just a “moonlighting paleontologist.” But Garcea was too intrigued to dismiss him as an interloper. She agreed to join him.

 Garcea explained that the Kiffian were a fishing-based culture and lived during the earliest wet period, between 8,000 and 10,000 years ago. She held a Kiffian sherd next to a Tenerian one. “What is so amazing is that the people who made these two pots lived more than a thousand years apart.”

 Over the next three weeks, Sereno and Garcea-along with five American excavators, five Tuareg guides, and five soldiers from Nigeria’s army, sent to protect the camp from bandits—made a detailed map of the site, which they dubbed Gobero, after the Tuareg name for the area. They exhumed eight burials and collected scores of artifacts from both cultures. In a dry lake bed adjacent to the dunes, they found dozens of fishhooks and harpoons carved from animal bone Apparently the Kiffian fishermen weren’t just going after small fry: Scattered near the dunes were the remains of Nile perch, a beast of a fish that can weigh nearly 300 pounds, as well as crocodile and hippo bones.

 Sereno flew home with the most important skeletons and artifacts and immediately began planning for the next field season. In the meantime, he carefully removed one tooth from each of four skulls and sent them to a lab for radiocarbon dating. The results pegged the age of the tightly bundled burials at roughly 9,000 years old, the heart of the Kiffian era. The smaller “sleeping” skeletons turned out to be about 6,000 years old, well within the Tenerian period. At least now the scientists knew who was who.

 In the fall of 2006 they returned to Gobero, accompanied by a larger dig crew and six additional scientists. Garcea hoped to excavate some 80 burials, and the team began digging. As the skeletons began to emerge from the dunes, each presented a fresh riddle, especially the Tenerian. A male skeleton had been buried with a finger in his mouth.

 Even at the site, Arizona State University bio archaeologist Chris Stojanowski could begin to piece together some clues. Judging by the bones, the Kiffian appeared to be a peaceful, hard working people. “The lack of head and forearm injuries suggests they weren’t doing much fighting,” he told me. “And these guys were strong.” He pointed to a long, narrow ridge running along a femur. “That’s the muscle attachment,” he said. “This individual had huge leg muscles, which means he was eating a lot of protein and had a strenuous lifestyle — both consistent with a fishing way of life.” For contrast, he showed me the femur of a Tenerian male. The ridge was barely perceptible. “This guy had a much less strenuous lifestyle,” he said, “which you might expect of a herder.”

 Stojanowski’s assessment that the Tenerian were herders fits the prevailing view among scholars of life in the Sahara 6,000 years ago, when drier conditions favored herding over hunting. But if the Tenerian were herders, Sereno pointed out, where were the herds? Among the hundreds of animal bones that had turned up at the site, none belonged to goats or sheep, and only three came from a cow species. “It’s not unusual for a herding culture not to slaughter their cattle, particularly in a cemetery, M Garcea responded, noting that even modern pastoralists, such as Niger’s Wodaabe, are loath to butcher even one animal in their herd. Perhaps, Sereno reasoned, the Tenerian at Gobero were a transitional group that had not fully adopted herding and still relied heavily on hunting and fishing.

Back in Arizona, Stojanowski continues to analyze the Gobero bones for clues to the Green Saharans’ health and diet. Other scientists are trying to derive DNA from the teeth, which could reveal the genetic origins of the Kiffian and Tenerian- and possibly link them to descendants living today. Sereno and Garcea estimate a hundred burials remain to be excavated. But as the harsh Tenere winds continue to erode the dunes, time is running out. “Every archaeological site has a life cycle,” Garcea said. “It begins when people begin to use the place, followed by disuse, then nature takes over, and finally it is gone. Gobero is at the end of its life.”