Comparison of Venus’ and Earth’s topography. For Venus, orange represents the topographic highs, blue the lows. For the Earth, red represents the highs and blue the lows.
Today I saw an interesting talk about Venusian geophysics by Dr. Steve Mackwell.
Dr. Mackwell talked about how mountains, volcanoes, craters, and fractures in Venus’ surface allow scientists to infer the tectonic history of Venus.
For example, unlike the Moon, there aren’t that many craters on the surface of Venus, which should have accumulated with time as more and more asteroids and comets struck the surface. This lack of craters (along with widespread, large-scale volcanic features) suggest that Venus underwent a tremendous volcanic upheaval about a half billion years ago, during which global volcanic eruptions almost completely re-surfaced the planet.
Dr. Mackwell also discussed how his lab experiments in rock mechanics (in which he squeezes and heats rocks to determine their physical properties) have contributed to our understanding of Venus’ history.
For example, the flow of heat from Venus’ interior drives its geophysical activity and plays a key role in determining the strength of the rocks underlying the surface topography. Understanding the relationship between internal heat flow and rock strength, however, requires lab experiments such as Dr. Mackwell’s.