Discussion Overview
The discussion revolves around the phenomenon of shadows cast by clouds over the sea, specifically addressing the lack of a visible edge in these shadows. Participants explore the theoretical implications of light and shadow, considering factors such as the sun's distance and size, the height of clouds, and the nature of light emission.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant notes that based on the sun's radius and distance, a 16-meter edge should be visible around the shadow, yet it is not easily seen.
- Another participant suggests that the spherical nature of the sun reduces the expected edge size to about 8 meters.
- A question is posed regarding the brightness levels in the penumbra compared to the umbra and the surrounding bright areas.
- Participants inquire about the viewing angle and distance from which the shadow is observed, as well as the actual altitude of the clouds.
- There is a discussion about the uniformity of brightness from the sun's surface and how this affects the perceived thickness of the penumbra.
- One participant argues that the shorter vertical slices of the sun's disk at the edges contribute less to the shadow effect, potentially making the penumbra appear thinner.
- Another participant questions the assumption of a totally opaque cloud affecting the shadow's visibility.
Areas of Agreement / Disagreement
Participants express differing views on the expected characteristics of the shadow and the factors influencing its visibility. There is no consensus on the reasons behind the lack of a visible edge in the shadows of clouds over the sea.
Contextual Notes
Participants rely on assumptions regarding distances and the nature of light emission, which may not be fully resolved in the discussion.