Eartha is the world's largest rotating and revolving globe, located within the headquarters of the DeLorme mapping corporation in Yarmouth, Maine. The globe weighs approximately 5,600 pounds (2,500 kg), and has a diameter of over 41 feet (12.5 m).
The globe was built with a scale of 1:1,000,000, on which one inch represents sixteen miles. As with most globes, it is mounted at a 23.5 degree angle, the same axial tilt as the Earth itself; thus the equator is diagonal to the floor. It uses a cantilever mount with two motors, and simulates one day's revolution and rotation every 18 minutes, though it is possible for the motors to fully rotate the globe in as little as one minute.
The globe was completed on July 23, 1998, after two years of construction and planning, and it uses a composite database built from satellite imagery, shaded relief, colored bathymetry, and information about road networks and urban areas. The database used to generate the surface images was approximately 140 gigabytes.
While former CEO of DeLorme Maps, David DeLorme, is credited with the design of the globe, Lewiston-based surveyor and civil engineer, Vincent J.P. Leblanc, was involved in the building project. Map technician Jeff Clark was "responsible" for each of the 792 plastic sections that cover the rotating globe.
Eartha is constructed around a truss structure which is called Omni-Span, and consists of over 6000 pieces of aluminum tubing. This is covered by a skin of 792 map panels, each covering 8 degrees of latitude and 10 degrees of longitude, and attached to the trusses with a custom-designed system of hidden bolts.
The atrium containing Eartha is open to the public during business hours. There is an adjacent gift shop that carries various DeLorme and geography related products. The mounting equipment is in a large pit below floor level and is visible to visitors, but the stairway down is chained off to prevent public access. There are two balconies that allow visitors to more easily view the higher parts of the globe. Some offices within the building also have views overlooking Eartha.
Eartha was originally designed to be 42 feet (12.8 m) in diameter. In 1999, surveyors hired by the Guinness Book of World Records measured the globe at 41 feet 1.5 inches (12.53 m); while this is noted on the DeLorme web site (as of 2007-09-05), they also list the globe as 41.5 feet (12.6 m) in diameter. David DeLorme, CEO of the DeLorme mapping company, is credited with the design. The previous record holder is the Globe of Peace located in Apecchio, Pesaro, Italy.
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