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Gravity field of venus: a preliminary analysis
Science (New York, N.Y.)
|July 6, 1979
Summary
The Pioneer Venus mission mapped Venus's gravity field, revealing anomalies. The northern plateau requires compensation at shallow depths, suggesting unique planetary processes compared to Earth.
Area of Science:
- Planetary Science
- Geophysics
- Gravimetry
Background:
- The gravity field of Venus is crucial for understanding its internal structure and geological processes.
- Previous missions provided limited high-resolution gravity data, necessitating further investigation.
Purpose of the Study:
- To map the line-of-sight gravity field of Venus using Pioneer Venus spacecraft data.
- To investigate gravity anomalies, particularly in relation to topography like the northern plateau.
- To compare Venus's gravity field characteristics with Earth's to infer differences in planetary evolution.
Main Methods:
- Line-of-sight gravity field mapping through tracking the Pioneer Venus spacecraft near periapsis.
- Analysis of gravity signatures across a specific longitudinal swath (294 to 339 degrees).
- Fourier decomposition of long-wavelength anomalies and spectral comparison with Earth's gravity data.
Main Results:
- Consistent, systematic variations in gravity signatures confirm the reality of observed anomalies.
- The northern plateau exhibits no corresponding gravity signature, implying significant isostatic compensation.
- Simulation modeling indicates compensation depths for the northern plateau are 100 km or less.
- Venus and Earth show similar gross power in their mean gravity spectra, but harmonic variations suggest differing dynamic processes or lithospheric behavior.
Conclusions:
- The northern plateau on Venus is compensated at shallow depths, indicating unique geological processes.
- Comparative spectral analysis reveals fundamental differences in the dynamic processes or lithospheric behavior between Venus and Earth.
- High-resolution gravity mapping provides critical insights into Venus's internal structure and evolution.
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