A sleek new European Space Agency satellite set to launch this year, perhaps as early as February, aims to map out the planet's gravitational field in unprecedented detail. The Gravity field and steady-state Ocean Circulation Explorer, or GOCE, will gather data useful for research in oceanography, solid Earth physics and climate change.
"ESA's gravity satellite will measure Earth's gravity from place to place around the globe to provide a uniform global picture," said GOCE project scientist Mark Drinkwater in a press release. "It will do this with a level of detail and accuracy never before achieved. This fundamental reference dataset will give access to new scientific insights into ocean circulation and its impact on climate, as well as into the structure of the interior of the Earth in critical locations such as earthquake and volcanic zones."
What goes up must come down. That simple explanation of gravity serves us well in most cases, but at a certain level, it breaks down. For example, the strength of Earth's gravity actually varies by small amounts at different spots around the planet.
GOCE will use ultrasensitive instruments called accelerometers to measure tiny variations in Earth's gravitational tug due to the planet's rotation, the positions of mountains and ocean trenches, and variations in the density of Earth's interior.
Orbiting low at just 155 miles above the surface of the planet, GOCE will compile its precise 3-D map of Earth's gravitational field over a period of about 20 months.
The information it gathers will also help scientists finally gauge accurate heights for major Earth features such as Mount Everest, for which today's best estimates vary by more than 16 feet.
"Measuring our planet's peaks using a standardized reference will help us better understand the Earth," said Bente Lilja Bye, research director from the Norwegian Mapping and Cadastre Authority.
"GOCE will result in an improved accuracy of the geoid and will facilitate the establishment of a unified global height system so that heights of the highest mountains in the world can be directly compared," she said. "Another benefit will be an improvement in our capabilities to predict the behavior of the Earth, and hence provide information needed to help mitigate disasters and economically damaging events."
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