From the Big Bang to Your Backyard

Invited outreach talk given to the Johns Creek High School Astronomy Club (Johns Creek, GA). Non-technical introduction to early-Universe cosmology: cosmic expansion, the thermal history of the Universe, and the cosmic microwave background. Also introduces amateur astrophotography, covering stacking, lucky imaging, light pollution, asteroid motion, solar imaging during the 2023 annular eclipse, and lunar mosaics. Supplementary files (animations shown in the talk; still frames in the PDF): S17_ceres_proper_motion_2023-04-09.gif: Dwarf planet 1 Ceres moving against background stars near galaxy NGC 4152. Astro-Tech AT80EDT, ZWO ASI585MC. S17_33-polyhymnia_proper_motion_2023-04-14.gif: Main-belt asteroid 33 Polyhymnia moving against background stars. Same equipment. S19_annular_eclipse_2023-10-14_mare_orientale_limb.mp4: Zoom from the full Moon to the Mare Orientale region of the lunar edge, overlaid with the October 14, 2023 annular eclipse to show the Moon’s profile against the Sun. Meade ETX125, OIII filter, solar film. Figures: the CMB map (ESA and the Planck Collaboration / NOIRLab, CC BY 4.0) and the particle inventory figure from Rafelski et al., Universe 9, 309 (2023), CC BY 4.0. All astrophotographs © Andrew James Steinmetz. Use of AI Tools: Slide drafting and layout preparation were done with the assistance of Claude Opus 5.5 (Anthropic). The content was directed, reviewed and edited by the author, who takes full responsibility for it. All research results and astrophotographs are the author's own.