Over the years, there have been various calls to increase and better represent astronomy in curricula. This is motivated by views within the astronomy and astronomy education communities that the awe, wonder, and interdisciplinary nature of astronomy has the potential to engage students in STEM across disciplines. Reviews of curricula have shown that astronomy topics are represented in most mandated curricula around the world and although there is a homogeneity of astronomy topics in most mandated curricula, this representation has its limitations. By using the Australian National Curriculum, the USA-based Next Generation Science Standards (NGSS), and the Swedish National Curriculum as examples, this study unpacks ideas around "How much astronomy is enough?", the mismatches between astronomy topics in curricula and what constitutes astronomical literacy within the context of the Big Ideas in Astronomy document. The results identify that there is a significant gap at the galactic and extragalactic scales when considering the typical progression of astronomy topics when considering the conceptual, spatial, and temporal scales of the topics. Specifically, topics in curricula jump from tangible concepts within the student's immediate and Solar System spatial scales in primary school to cosmological spatial scales in upper high school, without reference to spatial and conceptual connecting topics at galactic scales. Potential sample curriculum statements drawn from the Big Ideas are presented as a suggested curriculum inclusion. This curricula gap is identified as a potential source of a similar gap in education research in these topics at these levels, which in turn perpetuates the problem by there being a lack of research-based evidence for inclusion in the curriculum.