Geodesy – the study of a planet’s shape, orientation, and gravity field – is one of the most powerful methods for investigating planetary objects.  At the Earth and the Moon, high-precision geodetic measurements have transformed geodesy from a purely geophysical tool into one that has unlocked new insights into climate change, geology, geochemistry, hydrology, and more.  In this short course, we will discuss the prospects for similar giant leaps that could be enabled by modern geodetic observations beyond the Earth-Moon system, including at Mars, Venus, and Ocean Worlds. 

In a series of four lectures, we will:

  1. Review fundamental scientific advances enabled by geodetic data at the Earth and the Moon;
  2. Review the history of climate and volatiles on Mars and discuss how new gravity data would address related outstanding questions;
  3. Review the current state of knowledge on possible active geological processes on Venus like volcanism, subduction, and atmospheric dynamics and discuss how new topography and gravity data would address outstanding related questions;
  4. Review how geophysical measurements have detected subsurface water oceans on icy moons of the outer Solar System, and discuss how new geodetic data would address outstanding questions as to those oceans’ characterization and habitability. 

The lectures will cumulatively describe fundamental insights into planetary science that could be gained by geodesy throughout the Solar System


Lecture 1 – Theory, Earth, and the Moon – Anton Ermakov
“What geodesy gave us in the Earth-Moon system”

  1. How we figured out the shape of the Earth and what it told us about its interior
  2. How we figured out that the Earth crust is in the state of isostasy
  3. How geodesy helped us to accept plate tectonics
  4. How we constrained the loss of the Greenland and Antarctic ice sheets from the GRACE observations
  5. How GRAIL helped us understand the mechanism of lunar mascon formation

Lecture 2 – Mars – Ali Bramson
“Geophysical observations of ice and climate on Mars”

  1. Primer on Mars climate history
  2. Gravity, topography, and radar observations of the polar deposits
  3. Radar observations and the debate on mid-latitude ice
  4. Prospects for future static gravity fields to search for ice and elucidate climate history
  5. Prospects for future time-variable gravity fields to detect active climate processes

Lecture 3 – Venus – Peter James
“Active geological activity on Venus from gravity and topography”

  1. Primer on Venus’ divergent history with the Earth
  2. Current state of knowledge on recent or active geological activity: resurfacing, volcanism, and subduction
  3. Prospects for future gravity and topography data to constrain recent or active geological activity
  4. Prospects for future gravity data to constrain present-day atmospheric processes

Lecture 4 – Ocean Worlds – Francis Nimmo
“Detection and characterization of water oceans on icy moons from geodetic measurements”

  1. Overview of where oceans worlds are in the Solar System
  2. Past detection of oceans on Europa, Enceladus, and Titan – magnetic induction and geodesy
  3. Prospects for future geodetic measurements to constrain active deformation and tidal dissipation.
  4. Prospects for future gravity and topography data to characterize Europa/Enceladus ocean properties (e.g., depth to the ocean)
  5. Prospects for future geodetic data to constrain ocean habitability – rock/water interfaces, resurfacing, plate tectonics, etc.