Sure, here are a few conditional sentences based on the idea that without the sun, man would live in darkness:

1. **First Conditional (Real possibility in the future):**
- If the sun were to disappear, man would live in darkness.

2. **Second Conditional (Hypothetical situation in the present or future):**
- If there were no sun, man would live in darkness.

3. **Third Conditional (Hypothetical situation in the past):**
- If the sun had never existed, man would have lived in darkness.

4. **Mixed Conditional (Hypothetical past affecting the present):**
- If the sun had vanished millions of years ago, we would be living in darkness now.

These sentences explore different scenarios and time frames related to the absence of the sun and its impact on human life.