For two years in space apparatus, measuring the Earth's gravity, collected enough data to make a gravity map of unprecedented accuracy. It will help scientists reveal many interesting aspects of the "functioning" of the planet.
Interesting information has brought the scientific world European satellite GOCE (Gravity Field and Steady-State Ocean Circulation Explorer — explorer of the gravitational field and steady-state ocean currents). The results of his work GOCE team said at a conference in Munich.
Launched in 2009, the unit has six accelerometers, a hundred times more sensitive than any previously raised in orbit. "Researcher" can feel the attraction of the deviation in one desyatitrillionnuyu of normal levels. Because "Goce" is able to determine the shape of the geoid with an accuracy of 1-2 centimeters in height on a 100-km stretch.
The geoid is the surface of an ideal world ocean in the absence of winds, tides and currents, that is formed only by the force of gravity. And it has long been known, is not the same in different parts of the world, and it is not in its rotation, and the uneven distribution of mass in the depths of the earth.
Accordingly, to obtain data on the exact level of sea water in different parts of the planet (from a number of satellite-altimeter), and comparing them with a map of the geoid can get a lot of information about the circulation of water in the ocean, variations in sea level due to global climate change, to determine the dynamics Earth's ice sheets and so on.
Fragment of a new map. The strongest gravity — in the areas colored in yellow, the weakest — in the blue areas. The form of the geoid deliberately reinforced — for clarity differences in elevation multiplied 10,000 times. Knowledge of the exact shape of geoid is important for geodesy — a measure of the height of the world (Figure EPA, ESA / HPF / DLR)
What is even more interesting: GOCE sees variations in gravity with a highly detailed, which allows to notice the tectonic faults, calculate the mass distribution in the strata of the mountain ranges and other similar watch, hidden from view, the structural features of the earth.
Decrypting information from GOCE, scientists can observe the movement of magma in the depths beneath volcanoes or fixed features in the movement and interaction of the continental plates. Project participants say using GOCE has previously unknown details about the depths of the Himalayas, South-East Asia, the Andes and the Antarctic.
GOCE flies in a polar orbit. To reduce drag "investigator" made highly elongated and with smooth contours: with a length of 5.3 meters of its basal area is less than a square meter. A small tail helps stabilize the satellite in the correct position. Weak atmospheric drag is compensated continuously operating ion engine.
In the satellite has no moving parts, so they experienced any acceleration, even the smallest — is the result of the impact of the world (Figure ESA / AOES Medialab)
The European Space Agency said: "Gravimetry from GOCE helps deepen our knowledge about the processes that cause earthquakes, such as the recently devastated Japan. The earthquake was caused by the movement of tectonic plates under the ocean. It can not be observed directly from space. However, an earthquake creates a signature in gravity data, which can be used to understand the processes leading to these natural disasters and, ultimately, to predict such events. "
The period of low solar activity, GOCE helped longer planned to stay on their low orbit, and with lower consumption of the working body for the engine. This means European engineers claim that the satellite will work quietly, at least until the end of 2012 (when the funding ends the mission), and maybe to 2014 second (if the Europeans will allocate resources).
Between each turn of "gravity meter" around the world increases the accuracy of the map. Back in 2010 GOCE pleased geophysicists his draft card geoid, drawing from two months of measurements. Now she is substantially revised.
And it is not final. In the coming months and years, experts working with the satellite, expect substantial improvement of the form of our home world. This, of course, like all scientists who use it in their studies. But now they have the geoid, defined as neatly as ever.