Thousands of planets have been discovered orbiting nearby stars. How many of these worlds can we expect to be Earth-like? We explore this question from the perspective of astronomers, geologists, and historians. We look back at Earth’s geologic history to periods when our planet itself would appear very alien to us today. We study the nearby planets Venus and Mars, which were once more Earth-like than today. We discuss not only the evolution of Earth, Venus, and Mars as habitable worlds but also how human understanding of these planets has evolved. Finally, we apply these perspectives to the search for alien Earths in our galaxy. This interdisciplinary treatment of Earth, its neighboring planets, and planets being discovered around nearby stars allows us to consider the potentially unique position of Earth as a habitable world not only in space but in time.
Fall 2025 Undergraduate Courses
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Alien Earths (3)
Exploring Our Solar System (3)
Our Solar System is filled with an incredible diversity of objects. These include the sun and planets, of course, but also many hundreds of moons—some with exotic oceans, erupting volcanoes, or dynamic atmospheres. Billions of asteroids and comets inhabit the space between and beyond the planets. Each body is unique, and has followed its own evolutionary history. This class will explore our current understanding of the Solar System and emphasize similarities that unite the different bodies as well as the differences between them. We will develop an understanding of physical processes that occur on these bodies, including tectonics, impact cratering, volcanism, and processes operating in their interiors, oceans, and atmospheres. We will also discuss planets around nearby stars and the potential for life beyond Earth. Throughout the class, we will highlight the leading role that the University of Arizona has played in exploring our Solar System.
Course Objectives: Students who engage with this course will develop a broad understanding of many fundamental concepts in planetary science and gain an appreciation for the discoveries and reasoning that leads to this understanding. They will learn to collect their own data as well as gather relevant supporting information from a variety of outside sources. Throughout the semester students will be demonstrating their grasp of course material by composing written assignments at a level their peers outside of the class will understand (a.k.a., Students on the Street, or SOS). During the term project students will be assisted in working with telescopes to obtain astronomical images using their own smart phone cameras. Students will learn during in-class workshops how to use their own images to then construct a time-lapse animation. Expected Learning Outcomes: Upon successful completion of this course students will be able to (1) access and use information and data from a variety of sources, including their own activities, (2) critically evaluate this information and data for reliability in supporting fundamental concepts, (3) effectively communicate an understanding of these concepts to their SOS peers by synthesizing the information and data they have gathered, (4) demonstrate practical skills with a variety of software, including Word, Excel, Keynote, PowerPoint, and image/video editing apps.
The Science and Politics of Climate Change (3)
This course explores the science of climate change and the political and commercial issues related to global warming. The first part of the course focuses on the scientific basis of climate change. Students will investigate the concepts and principles required for understanding planetary climates. They will assess the observational evidence for climate change and quantify the relative roles of natural and human drivers in causing it. They will connect and compare recent changes to historical climate trends and examine predictions for the impact of future climate change on the environment and our lives. The second part of the course focuses on the political and commercial issues related to climate change mitigation. Students will analyze policies designed to reduce greenhouse gas emissions and explore their impacts from the perspectives of policymakers, commercial interests and the public.
Chemistry of the Solar System (3)
Abundance, origin, distribution, and chemical behavior of the chemical elements in the Solar System. Emphasis on applications of chemical equilibrium, photochemistry, and mineral phase equilibrium theory. Prerequisites: CHEM 142/152/162 and MATH 129 or their equivalents. PTYS 407 is required for the PTYS Minor. PTYS 407 is equivalent to CHEM 407 (not cross-listed).