How would the experience of day and night be different if the Earth did not rotate on its axis?

If the Earth did not rotate on its axis, the experience of day and night would be profoundly different from what we currently know. Here are some key changes to consider:

1. **Permanent Day and Night**: One side of the Earth would be in constant sunlight while the other side would be in perpetual darkness. This means that one hemisphere would experience continuous daylight, receiving solar energy all the time, while the opposite hemisphere would be enveloped in eternal night, receiving no direct sunlight.

2. **Temperature Extremes**: The side facing the Sun would heat up significantly, potentially leading to extremely high temperatures, while the dark side would become very cold, possibly freezing temperatures. The lack of rotation would also limit the mixing of air, leading to severe temperature gradients.

3. **Weather Patterns**: The weather would be drastically different as well. The sunlit side might experience frequent storms due to intense heating and rising air, which could cause significant atmospheric turbulence. On the dark side, the absence of sunlight could lead to stagnant air and potentially create conditions for ice formation.

4. **Ecosystems and Life**: The ecosystems would be dramatically altered. Organisms on the sunlit side would likely evolve to thrive in constant light, perhaps resembling desert flora and fauna. Meanwhile, life on the dark side would adapt to darkness, possibly evolving characteristics similar to those of creatures found in deep caves or ocean floors. Photosynthesis, as we understand it, would be limited to one side of the planet.

5. **Biorhythms and Biological Effects**: The circadian rhythms that many organisms rely on would be severely disrupted. Species that depend on day-night cycles for reproduction, feeding, and sleeping would struggle to adapt to a world with no regular day-night cycle.

6. **Geological Impact**: The lack of rotation would also affect geological processes. The redistribution of heat might lead to different tectonic activities, potential changes in volcanic activity, and the formation of different landscape features due to the persistent heating on one side.

7. **Cultural Impacts**: Human societies would also change drastically. Cultures would develop with a vastly different relationship to time and light. Activities that depend on light cycles, such as farming, would have to adapt significantly to the unique conditions of the sunlit or dark sides.

In summary, a non-rotating Earth would lead to a stark division between constant light and dark, with profound effects on climate, ecosystems, and life as we know it. The world would be a very different place, both physically and culturally.