Discussion Overview
The discussion centers around the speed at which a human-sized object would need to move to be undetectable by the human eye, particularly in the context of fictional representations like the Flash. Participants explore various factors influencing visibility, including speed, viewing angle, and environmental conditions.
Discussion Character
- Exploratory
- Debate/contested
- Conceptual clarification
Main Points Raised
- One participant questions whether Mach 2 speed (2469 km per hour) would be sufficient for a human-sized object to be completely unseen when passing nearby.
- Another participant suggests that the Flash's speed is a narrative device rather than a reflection of physical reality, indicating that fictional characters often operate outside coherent physical laws.
- Some participants mention the potential impact of a supersonic shock wave, which could draw attention regardless of the object's speed.
- Visibility is influenced by factors such as viewing angle, light conditions, and the observer's concentration, with one participant noting that they sometimes fail to notice people at normal walking speeds.
- A later reply emphasizes that the angle at which one views the object affects how long it remains in the field of view and its perceived speed, suggesting that this is more about human perception than physics alone.
- Another participant argues that the question is fundamentally about speed and not biology, expressing frustration over the lack of numerical answers.
- There are references to subliminal cuts in movies, indicating that brief visibility may not be processed by the brain, but this does not provide a specific speed requirement.
Areas of Agreement / Disagreement
Participants express differing views on the relevance of biological factors in determining visibility, with some insisting that the question is purely about speed while others argue that human perception plays a significant role. Overall, the discussion remains unresolved with multiple competing perspectives on the factors affecting visibility.
Contextual Notes
Limitations include the lack of specific numerical answers regarding the necessary speed for undetectability and the dependence on various subjective factors like concentration and environmental conditions.