Though we live in a 4-dimensional universe, our minds and bodies are not particularly good at perceiving and depicting 4 dimensions. This study contributes to our understanding of collaboration with abstract concepts by examining particular activities where bodily and experiential understandings may conflict with the conceptual domain. Specifically, upper secondary physics classrooms studying Einstein's general theory of relativity are taken as a setting to identify the representational practices and conceptual challenges that arise when learners attempt to make meaning with, and express conflicting notions of, space and time. To unpack these challenges, we draw on the concept of imagination and on theoretical perspectives that treat imagining as a social activity. We also present the concept of metaimagining to characterize layered processes in which learners attend to and manage shifts between their own imaginative activities. This concept is illustrated through a detailed analysis of an extended conversation between 2 upper secondary physics students working with general relativity and spacetime. The students perform a diverse set of imaginative activities that are strongly tied to communicative, cognitive, and bodily action. We also show how the unique domain of general relativity presents particular challenges to student meaning making of abstract concepts which in turn prompt metaimagining. Based on our analysis, we offer recommendations to improve instructional practices in general relativity and argue for the consideration of imagining as a transdisciplinary competency in math and science education.