NASA has released a gravity-based visualization of Earth known as a geoid, depicting the planet as an irregular, lumpy shape rather than a smooth sphere. Based on over one billion satellite measurements, the model illustrates how gravity varies across the globe, though the visual distortions are exaggerated by 10,000 times to remain visible.
A viral image of a bruised, golden blob—often captioned as the real shape of the Earth
—has sparked widespread social media debate, with some users questioning if the planet is actually shaped like a potato. However, scientists clarify that the image is not a photograph of the Earth’s physical surface, but a scientific model called a geoid.
The geoid represents a theoretical surface where the ocean would settle if it were influenced only by gravity and Earth’s rotation, stripped of the effects of winds, tides, and currents. Because mass is not distributed evenly inside the planet, gravity does not pull with the same strength everywhere. Denser rock or magma creates gravitational hills
, while lower-density material forms gravitational valleys
.
The 10,000x Scale of Gravitational Anomalies
To the naked eye, Earth remains an oblate spheroid—essentially a sphere slightly flattened at the poles and bulging at the equator. The irregularities shown in the geoid model are so subtle that they would be virtually imperceptible at their true scale. To make these variations visible, NASA amplified the distortions by a factor of 10,000.
When viewed without this exaggeration, the differences in the gravitational field are minimal. According to ScienceABC, the high and low spots differ by only about 191 meters (627 feet). This leaves the actual planet smoother than a billiard ball, despite the “lumpy” appearance of the model.
| Gravitational Feature | Location | Elevation Relative to Average |
|---|---|---|
| Highest Point | Near Iceland | Approximately 279 feet above |
| Lowest Point | South of India | Approximately 348 feet below |
Satellite Data from GOCE and GRACE
Producing the geoid required 15 years of data collection and more than one billion measurements. The model, known as the GOCO06 global model, synthesized data from 19 different satellites. Central to this effort were the European Space Agency’s GOCE mission and NASA’s GRACE program, the latter of which was developed with the German Aerospace Center.
The GRACE mission utilized a unique technique involving two identical spacecraft flying 220 kilometers apart. By measuring minute fluctuations in gravity between the two craft, scientists could track the movement of mass across the planet’s surface.
This precision was further validated through international cooperation. Brazil contributed to validating the results by comparing them with ground-based measurements from the Brazilian Institute of Geography and Statistics, alongside data from Germany, Japan, and the United States.
Practical Applications of the Geoid Model
While the “potato Earth” image is a visual curiosity, the geoid is a critical tool for modern geodesy and navigation. Most traditional maps rely on a simplified ellipsoid shape for ease of calculation, but the geoid provides the irregular precision necessary for improving GPS accuracy and calculating sea levels more precisely.
Beyond navigation, the model allows researchers to monitor the planet’s dynamic systems.
- The Global Water Cycle: Assessing groundwater reserves for agriculture and tracking rainfall patterns.
- Climate Change: Measuring long-term sea level rise and monitoring the loss of polar ice.
- Geophysics: Studying the movement of tectonic plates and the distribution of mass within the Earth’s interior.
Despite these advances, some challenges remain. According to reporting from upday News, measuring deep soil water content and its annual variations remains challenging, though the gravitational field data provides a crucial tool for analyzing the hydrological cycle and understanding water availability.
Ultimately, the geoid model does not replace the “Blue Marble” images of a spherical Earth; rather, it adds a layer of nuance. It transforms an invisible force—gravity—into a visual map, revealing the complex internal structure of a planet that is far more dynamic than a classroom globe suggests.
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