Is Mount Everest growing? A band of mountain climbers and researchers recently lugged the latest in GPS (Global Positioning System) technology to the top of the Everest summit to find out.
A climbing team led by noted American mountain climber Wally Berg and financed in part by the Boston Science Museum traversed Everest's daunting face with a newly revamped GPS device manufactured by Sunnyvale, California-based Trimble.
"The key for this expedition was that [the GPS device] was incredibly easy to operate, just a button to push, and the entire system is housed in a single enclosure," said Mike Jackson, program manager for large contracts at Trimble. "Normally, you have an external battery and an external antenna, meaning that usually the weight and size is very large, but this one we got down to the size of a large cantaloupe so it can be operated very easily."
Once at the summit, Berg and his team took two hours to drill a hole and place a steel bolt into the rock on the face of the summit. Trimble's GPS equipment was attached to that bolt, which will be used as a benchmark for future measurements.
GPS technology uses a network of satellites to provide extremely accurate readings, which are also used in automobile location machines and nautical devices. For geologists, the problem to date has been the lack of pinpoint accuracy in measuring Everest's full height. Traditional surveying technology has been unable to give an exact reading because Everest's snowcap hat rises and falls depending on the month and year. Until now, measurements for Everest's height have come from a survey conducted back in the 1950s.
While still too early for researchers to say with certainty whether Everest is growing, preliminary numbers point to a growth rate of one to two centimeters a year -- though the actual height of the mountain might stay constant due to soil erosion.
The latest expedition came at the heels of a failed attempt last year. The earlier try was thwarted by GPS equipment too heavy and bulky for the climbers to drag to the top. The older GPS system had to be hauled up the mountain in separate parts, making the trek considerably riskier and more difficult. Conditions at the top of the world require that the equipment be as compact and light as possible. Temperatures on Everest can fall as low as minus 45 degrees Fahrenheit and the thin air pressure causes computers to crash -- in addition to having the potential to kill an improperly acclimated person in a couple of hours.
This time around, Trimble capitalized on improvements in component miniaturization to provide the team with five Trimble 4800 receivers, each of them a fully contained unit combining an antenna and computer receiver in one relatively small package. From Everest, information from these devices was logged and transmitted by satellite phone to researchers at MIT for further analysis. The GPS device logged 71,000 individual observations over a two-day period before its lithium ion battery ran out. A second climbing team retrieved the GPS device five days later.
But for the mountain climbers participating in the project, scientific inquiry was only part of the appeal. "The science part is a rather neat experiment to go run, but it's a fun mountain to climb, although it's certainly nice to get oneself a footnote in terms of Everest history," says Charles Corfield, a mathematician by training, a veteran of several Silicon Valley start-ups, and the science officer in the climbing team.
Geologists previously hypothesized that Everest is growing at a rate of about an inch per year as the colliding continental plates under India and China cause it to slowly inch skyward. While cartographers and surveyors debate whether the earth is capable of producing mountains taller than Everest's currently accepted 29,028 feet (a figure the GPS equipment showed to be slightly off), people living in the earthquake-prone region of the Himalayans might be interested for other reasons. Accurate readings of Everest's growth could point to underground seismic activity, helping geologists make future earthquake predictions in the region.
Having a working GPS system spread across Everest connected with medical monitoring technology could also provide valuable medical data on the physiological changes that occur during mountain climbing, according to Matt Lau, a researcher at MIT involved with the Everest project.
The 1998 American Everest Expedition was organized by Bradford Washburn of the Boston Museum of Science and sponsored in part by the National Geographic Society. The climbing team consisted of Berg, Corfield, David Mencin, a GPS expert, Eric Simsonson, and Greg Wilson.
