Daniel and Kelly’s Extraordinary Universe The physics of shadows
Nov 27, 2025
Explore the fascinating physics of shadows as the hosts dive into whether they can move faster than light. Discover the secrets behind overlapping penumbras and the mysterious 'shadow blister' effect. Learn about lunar shadows and Eratosthenes' ingenious method to estimate Earth's circumference. Delve into the colorful world of multi-color shadows and the unique effects of light under water. Finally, unravel the phenomenon of shadow bands during solar eclipses and their connection to diffraction. Shadows reveal a universe of wonders!
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Shadows Are Absences Shaped By Geometry
- Shadows are simply regions lacking direct light and are shaped by geometry and multiple light sources.
- Penumbras from extended or additional lights make most everyday shadows fuzzy rather than perfectly crisp.
Moon Shadows on a Clear Night
- Kelly fondly recalls seeing sharp moon shadows on clear nights in low light-pollution Virginia.
- She describes those moonlit shadows as spooky and fantastic, showing everyday wonder in nature.
Why Everyday Shadows Are Fuzzy
- Extended light sources act like many point sources and create overlapping shadows and penumbras.
- Reflections from room surfaces further soften shadows by redirecting light into darker regions.
