738 What Can Venus Tell Us about Earth’s Climate: Making the Case to Study Other Planets to Solve Earth’s Mysteries

Tuesday, 9 January 2018
Exhibit Hall 3 (ACC) (Austin, Texas)
Erika Kohler, NASA, Greenbelt, MD

Venus is startlingly familiar and at the same time fundamentally alien. Despite its similarities to Earth in mass, size, distance from the sun, and geological composition, its climate has evolved to something very different from Earth’s. But its similarities and differences make it the perfect natural laboratory for studying Earth’s past, present, and future.

Starting out with similar origins to Earth, it is expected that at one time Venus had surface oceans, a more temperate climate, and may have even been capable of hosting life. But at some point, Venus’ evolutionary path diverged from Earth. The Venusian atmosphere presents an extreme case of the role of the greenhouse effect on global warming and its slow rotation reduces the Coriolis force by two orders of magnitude. Seasons are nonexistent due to the lack of axial tilt and the recent discovery of an ozone layer provides an excellent atmospheric comparison study. Studying how our neighboring planet operates under a significantly different set of environmental conditions enables a better understanding of planetary atmospheres, climate, and extreme weather.

But Venus isn’t the only planet with an atmosphere, or with analogs that can inform Earth science. Meteorological studies of planets with simpler weather patterns may help explain our own. Jupiter has a faster rotation rates, and belts that are similar to our jet stream. Mars is mountainous while Venus is flat which can be used to study the effect of topography on weather patterns. Mars has large sandstorms and dust devils. Venus has sulfuric acid clouds, which could help us understand acid rain and the role aerosols play in an atmosphere. Jupiter’s Great Red Spot shows similarities to our own hurricanes. And Saturn’s moon Titan has an atmosphere of predominantly nitrogen like Earth’s, but with rain consisting of methane. And the new field of exoplanets gives us insight into cloud formation as well as demonstrating that the diversity of atmospheres is greater than we ever expected. Earth is a complex system which makes weather difficult to predict. By utilizing other examples in our own backyard, we will be able to understand the basics of meteorology better.

Often overlooked is that the history of our own planet is an exercise in comparative climatology itself. "Snowball Earth" periods, the equable climate of the Eocene, and the very "alien" non-oxygenated but still life-supporting Archean, in effect can be thought of as different planets relative to modern Earth.

Evidence of extreme weather and changing climates exist in both our past and on other planets. Studying the atmospheres of other planets can force science to confront the fundamental understanding of some of the processes that exist on Earth, particularly those that we sometimes trick ourselves into thinking we understand more deeply than we do. This will only lead to a greater understanding of the world and worlds around us.

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