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GOCE depicts gravity in high resolution

Some 1,200 Participants of the European Space Agency’s (ESA) Living Planet Symposium in Bergen, Norway, got a first glimpse today of a geoid map produced by GOCE, ESA’s Gravity Field and Steady-State Ocean Circulation Explorer.

GOCE.jpg

Image: ESA – Colours show the height differences – in metres – in an idealized motionless global ocean due to density anomalies in the Earth’s interior.

The Earth’s geoid, a concept first described by 19th century German mathematician Carl Friedrich Gauss, is a visualization of what the idealized planetary surface would look like if the force of gravity was everywhere perpendicular – like in a global ocean without tides and currents.

GOCE, launched in March 2009, is measuring Earth’s gravity with unprecedented accuracy and resolution. The so-produced maps and data could help scientists precisely measure changes in ocean circulation, sea-level and ice caps – all of which are affected by climate change.

“With each two-month cycle of data, the gravity model will become more detailed and accurate,” says Reiner Rummel, chairman of the GOCE mission advisory group.

As gravitational variations are stronger closer to Earth, GOCE orbits at an altitude of merely 255 kiolmetres – the lowest of any Earth observation satellite. To counter the effect of strong residual air, which would otherwise quickly decay its orbit, the satellite engine continuously fires xenon ions at high velocities.

“The gravity measuring system is functioning extremely well. The system is actively compensating for the effects of atmospheric drag and delivering a continuous set of clean gravity readings,” says GOCE mission manager Rune Floberghagen Floberghagen.

The final gravity map and geoid model is to advance research in a broad range of fields, from oceanography to geodesy and earthquake research.

Comments

  1. Report this comment

    Murali said:

    Can you please explain what the color code stands for. So that it would make some sense to lay man like me. Thanks

  2. Report this comment

    Graeme said:

    My science teachers always told me that a graph without labels and scales on the axes was useless.

    We can guess what the x-y axes are, given that it is a map, but what is the scale of these “tiny variations”?

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    mollwollfumble said:

    The results in this figure are not at all those that I would expect. Gravity charts of the world that I’ve seen before show high intensity over the Himalayas and low intensity over the deep ocean trenches. This one shows lowest intensity over Southern India, and highest over New Guinea. So I presume that terrain height effects have been pre-subtracted. If so, then it becomes a real question as to what this is showing, I would love it to be showing upwelling and downwelling in the Mantle, but can’t be sure that that is what I’m really seeing here.

  4. Report this comment

    Stanley V Byers said:

     

    The major gravity anomalies on this map show as matching pairs on opposing sides of Earth. This phenomenon is only predicted by a radiation pressure model of gravitation. An illustration of the phenomenon is provided at the URL http://home.netcom.com/~sbyers11/grav11d.htm

    The units for the color legend on the GOCE map may be meters. Minus 100m and plus 80m would then correspond to the difference in low and high points in the Earths surface if it were covered with water. This new GOCE data would then closely correspond to the 1979 Seasat satellite data.

  5. Report this comment

    Stanley V Byers said:

    The major gravity anomalies on this map show as matching pairs on opposing sides of Earth. This phenomenon is only predicted by a radiation pressure model of gravitation. An illustration of the phenomenon is provided at the URL http://home.netcom.com/~sbyers11/grav11d.htm .

    The units for the color legend on the GOCE map may be meters. Minus 100m and plus 80m would then correspond to the difference in low and high points in the Earth’s surface if it were covered with water. This new GOCE data would then closely correspond to the 1978 Seasat satellite data.

  6. Report this comment

    Stanley V Byers said:

    For readers who may still entertain the “mass attraction” and General Relativity concepts of gravity and these anomalies, the following paradox is presented.

    If the seat and cause of the “apparent” attraction force is “internal” to each of the bodies,…the attraction concept produces twice the force that is necessary to balance the centrifugal orbital forces of a planet moon system.

    The concept of “attraction” between bodies requires that the force from each separate body acts equally on each body.

    This is demonstrated by tension on a rope, each end has an equal amount of oppositely directed force.

    With the attraction concept, when one is on Earth the concept requires that Earth’s gravity of one g is attracting the Moon, and this same and equal Earth attraction force is pulling the Earth toward the Moon. Now, when one is on the Moon the Moon’s gravity of 0.166 gs is attracting the Earth and this Moon attracting force is equally pulling the Moon toward the Earth.

    Using Newton’s equation the g force for each of the “two” bodies attracting the other can be calculated, and it is found that they are equal and there is now twice the force required to balance the centrifugal forces of orbit.

    This paradox only arises within the mass “attraction” concept. In an isotropic radiation pressure system the seat of the force is not in the mass of the objects, each atom of the object shadows the radiation flow, causing an “external” unbalanced radiation pressure force pushing the objects toward each other. There is no attracting tension which requires the doubling of the calculated force involved. The gravitational pressure is an attribute of the Universe,…in the same manner that Inertial and all remote forces demonstrate.

    The attraction concept accepts Newton’s inverse square equation of gravity’s force between two bodies as:

    F = G x (M1 x M2) / r squared

    The surface gravity ( g ) for each of the bodies can be derived from the gravitational constant ( G ) and the mass and radius of the bodies.

    In summary; If the Earth is attracting the Moon and the Moon is attracting the Earth, there would exist twice the actual force required to maintain the Moon’s orbit. This doubling of force demonstrates that the seat of force does not reside in the planets. The seat and cause of the forces is external to the planets as demonstrated by a radiation pressure model of remote force.

    The exact same paradox arises with the General Relativity (GR) concept of gravity. It postulates that Mass warps their hypothetical “fabric of space” and the warped fabric of space causes attraction of other masses. Since in the GR theory the seat of the force is within the planet and moon we would again have twice the force required to balance the orbital forces of the Earth Moon system.

    This logic of this article does not imply that there is anything wrong with Newton’s gravitational equation;…the double force error only arises when it is assumed that the cause and seat of the force is attractive and therefore originates within the planets or bodies.

    This paradox does not arise within a radiation and shadowing system, since the seat and/or source of the force is external to the planets and moons,…and attraction or tension are not required and cannot exist within a radiation pressure and shielding system of remote and local forces.

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