ESA's GOCE Satellite Provides Gravity Map of Earth 119
kaulike writes "The European Space Agency's GOCE satellite, launched in March 2009, has provided a spectacular, highly detailed map of our favorite gravity well. This map shows the normalized surface of the earth as defined by gravity, showing the relative altitude differences from the average for each surveyed point. The article provides the helpful metaphor that a ball resting on this surface would not roll anywhere, even though there would be visual slopes, as gravity is equalized across the globe. There is a fascinating deep area in the Indian ocean (-100M) and a high area near Iceland (+80M), proving conclusively that our world is not homogeneous in terms of density (or practically any other measure). Does anyone know whether these anomalies correspond to known geographic phenomena? Deposits of heavy metals perhaps, or hotspots where the mantle is thinner? I know little about geodetic stuff, but I'm curious about the reasons for wrinkles in the data set."
Where's a 1920x1200pxl Image? (Score:3, Interesting)
That's a really nice image. Where can I find a 1920x1200 pixel image file of it to use as desktop wallpaper?
cool (Score:5, Interesting)
this is quite a very informative article.
my question though from the image produced is that the metres/meters scale shows how "strong" or "weak" the gravity is from the normalized sphere? how is it in the unit of metres/meters? i would appreciate if someone could explain the map more detailed (i probably need another explanation from the article to understand it more.)
the goce satellite is cool. i mean i didn't realize that we have technology such as xenon ion thrusters. i thought they were limited to star trek. my ignorance. :((
thanks in advance. :)
Interesting Pattern Near the Ring of Fire (Score:5, Interesting)
Got KML? (Score:4, Interesting)
Re:Interesting Pattern Near the Ring of Fire (Score:3, Interesting)
Re:wonder why they duplciated US GRACE satellite? (Score:4, Interesting)
Grace and GOCE are completely different experiments, which measure different (but related) things about the Earth's gravity field. Grace tracks the motions of a pair of satellites, which GOCE uses pairs of accelerometers. Different data types, different measurement errors, different types of systematic errors. I think it is well worth running both experiments.
Re:Some background: The Satellite Itself (Score:3, Interesting)
> That's some serious engineering precision.
If that is your cup of tea, then you will be interested in the in-development https://secure.wikimedia.org/wikipedia/en/wiki/Gaia_probe [wikimedia.org] : it will measure arcs of the order of the diameter of a hair from 1000 km away !!
Re:Some background: The Satellite Itself (Score:2, Interesting)
Apparently, the accelerometers themselves (3 pairs of them) are mounted to within one picometre
No they are not. That is entirely impossible to do, as this is quite a bit smaller than atomar scale.
Even looking at them with too many photons would already change their position by more than that.
Their relative position is measured to that precision in service.