30 September 2009
Following the launch and in-orbit testing of the most sophisticated gravity mission ever built, ESA’s GOCE satellite is now in ‘measurement mode’, mapping tiny variations in Earth’s gravity in unprecedented detail.
The ‘Gravity field and steady-state Ocean Circulation Explorer’ (GOCE) satellite was launched on 17 March from northern Russia. The data now being received will lead to a better understanding of Earth’s gravity, which is important for understanding how our planet works.
It is often assumed that gravity exerts an equal force everywhere on Earth. However, owing to factors such as the rotation of the planet, the effects of mountains and ocean trenches, and density variations in Earth’s interior, this fundamental force is not quite the same all over.
Credit:ESAOver two six-month uninterrupted periods, GOCE will map these subtle variations with extreme detail and accuracy. This will result in a unique model of the ‘geoid’ – the surface of an ideal global ocean at rest.
A precise knowledge of the geoid is crucial for accurate measurement of ocean circulation and sea-level change, both of which are influenced by climate. The data from GOCE are also much-needed to understand the processes occurring inside Earth. In addition, by providing a global reference to compare heights anywhere in the world, the GOCE-derived geoid will be used for practical applications in areas such as surveying and levelling.See More here and here
See:Plato's Nightlight Mining Company is claiming Aristarchus Crater and Surrounding Region and the rest is history:)
Should I assume that gravity map is based on the gravity that would be on the Earth's surface if it were not rotating; ie that the centripetal acceleration has been taken out? Doing that would make the map more inherently useful about the structure of the Earth per se. But the "geoid" is based on an ocean "at rest" meaning the water at "rest", not the Earth "not rotating." Hence the latter would include rotational effects. Do you know, which is shown? tx, and may I plug yet more intense quantum wrangling at name link.
ReplyDeleteHi Neil,
ReplyDeleteI have been tracking this for a while. I mentioned to Bee about "anchoring in reality" I had to move quickly to understand how gravity can be discerned on earth with the measures we have secured in terms of time clocks and sound.
Also consider this below
GOCE delivering data for best gravity map ever
Gravity is stronger closer to Earth, so GOCE was designed to orbit as low as possible while remaining stable as it flies through the fringes of our atmosphere. To help avoid drag and ensure that the gravity measurements are of true gravity, the satellite has to be kept stable in ‘free fall’. Any buffeting from residual air at this low altitude could potentially drown out the gravity data.
Bold added for emphasis
There is a correlation to the determination of blackholes by understanding Escape Energy for Photon?
Best,
Black Hole Conditions
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