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Fallacy of the GRACE Project, Gravity from Space not the same as Gravity on surface of the planet.
OR: take it to a journal
I also noted this on the Gravity on Earth (talk) page.
Looking at the GRACE project Geoid, I quickly noticed that the highest gravity is at the mountain ranges (Andes, Rockys, Himalayans, etc.). This would be the gravity as seen from space which would include the highest mountain peaks (more rock), and parts of the planet closest to the satellite.
The problem is that the gravity experienced at the surface of the earth is also dependent on the distance from the center of the Earth. So, the gravity experienced at the surface of the earth from the highest peaks is actually LOWEST. In fact, in the Gravity on Earth page, it says that the gravity at the peak of Mt. Everest decreases by 0.28%, or 9.8 m/s2 --> 9.77 m/s2.
The Grace Geoid also doesn't seem to take into account the Centrifugal effects on gravity as experienced in the equatorial regions, or the effects of the "bulge" which effectively increases the altitude in the equatorial regions.--Keelec (talk) 03:50, 13 December 2010 (UTC) — Preceding unsigned comment added by Keelec (talk • contribs)
Except that Wikipedia is not a source of original research, so unless you find secondary sources discussing the same thing, it's pretty much moot. – Kerαunoςcopia◁galaxies 18:44, 9 March 2011 (UTC)
It doesn't show gravity, it shows gravity anomaly. But, ditto above, without secondary sources - -original research. — HELLKNOWZ ▎TALK 22:38, 15 February 2012 (UTC)
GRACE doesn't measure gravity as experienced on the surface of the earth (what you're talking about, Keelec); it's measuring the variations in the earth's gravity field as sensed from orbit, which is determined by the arrangement of the mass constituting the earth. This is not a "fallacy" of GRACE, but simply a different thing being measured. The GRACE results don't mean you will experience the highest gravity when standing on top of the mountain ranges - it means that if you're a satellite orbiting above the earth, you will be pulled by more gravity when you're above the ranges, since there is more mass beneath you. Is there some clarification needed in the text on the page to make this more clear, somehow? Is this a likely misunderstanding that could arise, or is Keelec's interpretation uncommon enough that it should be ignored? 188.8.131.52 (talk) 22:11, 6 March 2012 (UTC)
GOCE has a Mission objectives section which states the expected accuracy of measurements. It would be great if this article on GRACE also had, so we can more easily compare the missions. - Rod57 (talk) 08:56, 20 November 2012 (UTC)