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Fraser
2011-Mar-31, 03:40 PM
Although they don’t like the comparison, scientists from the GOCE satellite had to admit that new data showing Earth’s gravity field – or geoid — makes our planet look like a rotating potato. After just two years in orbit, ESA’s sleek and sexy GOCE satellite (Gravity Field and Steady-State Ocean Circulation Explorer) has gathered sufficient [...]

More... (http://www.universetoday.com/84532/new-results-from-goce-earth-is-a-rotating-potato/)

George
2011-Apr-01, 01:41 PM
I assume that the physical representation would be about opposite of what is presented. The bulges near the poles would be low places on the planet, which would have a higher gravitational field. The greater spin we have at the equator would therefore have less of a gravitational field but would produce a slight bulge, opposite of the cool 3D presentation.

IsaacKuo
2011-Apr-01, 02:14 PM
No, it has nothing directly to do with the gravitational field at the surface of the Earth. Remember, GOCE was a satellite in a circular orbit. It wasn't following the surface of the Earth. The measurements were used to calculate the distribution of mass concentrations. The physical representation would be regions where the density was greater or lesser.

IsaacKuo
2011-Apr-01, 02:18 PM
Oh, and the GOCE satellite is truly sleek and sexy. Aerodynamic! Wings! Tail fins! Even a continuously burning main thruster in the tail!

Seriously, the sun-synchronous orbit, atmosphere skimming orbit, and 40km/s ion thruster makes the GOCE satellite very similar to a concept that's dear to my heart--an atmospheric scooping satellite. Such a satellite would be similar to GOCE, but with an air intake in the front and hardware to compress/cool LOX out of it (using waste nitrogen for ion thruster propellant to maintain orbit). Alternatively, an aeroscoop satellite could generate nitrous oxide, which could be used either as an oxidizer or a monopropellant.

George
2011-Apr-01, 02:47 PM
No, it has nothing directly to do with the gravitational field at the surface of the Earth. Remember, GOCE was a satellite in a circular orbit. It wasn't following the surface of the Earth. The measurements were used to calculate the distribution of mass concentrations. The physical representation would be regions where the density was greater or lesser.So the bulges represent higher density areas only; weaker density for the valleys. That wasn't clear in the article. Therefore, the physical shape would have little to do with what is seen in the animation.

Thanks for the clarity.

George
2011-Apr-01, 02:48 PM
Oh, and the GOCE satellite is truly sleek and sexy. Aerodynamic! Wings! Tail fins! Even a continuously burning main thruster in the tail!

Seriously, the sun-synchronous orbit, atmosphere skimming orbit, and 40km/s ion thruster makes the GOCE satellite very similar to a concept that's dear to my heart--an atmospheric scooping satellite. Such a satellite would be similar to GOCE, but with an air intake in the front and hardware to compress/cool LOX out of it (using waste nitrogen for ion thruster propellant to maintain orbit). Alternatively, an aeroscoop satellite could generate nitrous oxide, which could be used either as an oxidizer or a monopropellant. That's amazing. I would have guessed the drag would make the dip unproductive.