Uncovering Astronomy Students’ Understandings of the Age of the Universe: A Literature Review

Most education reform documents describing what students should understand about astronomy include concepts surrounding the immense size scale and ancient age of our Universe. If an appreciation for "deep time” is needed to develop mastery of astronomical concepts, then astronomy educators need to become aware of how students, and the general public, think about concepts of immense timescales. As a first step toward addressing this issue, we conducted a survey of the educational research literature on students’ conceptions of long timescales. Most recent research efforts have focused on two strategies. One is to show figures illustrating geologic strata to students who are asked to determine the sequence of events based on the concepts of original horizontality and superposition with younger sediments overlying older sediments. The other research design is to employ a card-sorting technique where people are asked to arrange events in order in relative sequence and sometimes asked to space them on a timeline. The key finding is that students can often place historical events in the correct relative order but are unable to place them with correct relative spacing or accurate absolute dates. Other findings are that current research does not reveal gender or racial biases in student thinking and it does not show that students always distinguish between the Big Bang and the formation of the Sun or Earth. It is clear that researchers in earth science education have not focused on cosmological time frames, only geologic time frames, thus leaving an important deficit in the literature. Prior to turning our attention to curriculum materials development focused on improving student understanding of long timescales in astronomy, we plan to expand these studies to include cosmological events.