In the universe where 'aether-sonis' permeates the vacuum, the crew in the nearby ship would experience the explosion as follows:

### **Visual Experience**  
They would see the explosion **immediately** (limited only by the speed of light, \( c \)) as photons from the blast travel through space. The visual display would include bright flashes, expanding fireballs, debris, and any other electromagnetic radiation emitted during the explosion. This aligns with real-world physics, where light requires no medium and travels at \( c \).

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### **Auditory Experience**  
The crew would hear the explosion after a **delay**, determined by two factors:  
1. **Speed of vibrations in aether-sonis**: If aether-sonis transmits sound at a speed \( v_{\text{sound}} \) slower than \( c \), the sound would arrive later. For example, if \( v_{\text{sound}} = 343 \, \text{m/s} \) (analogous to Earth’s air), a 1 km distance would result in a ~3-second delay.  
2. **Interaction with the ship**: The aether-sonis vibrations would strike the nearby ship’s hull, transferring energy to its structure. This would create mechanical vibrations inside the pressurized cockpit, which the crew would perceive as sound waves in their breathable atmosphere.

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### **Simultaneity**  
The crew would **not** experience the visual and auditory signals simultaneously **unless \( v_{\text{sound}} = c \)**. In most realistic scenarios, \( v_{\text{sound}} \ll c \), leading to a distinct delay. For instance, if the ships are 1 light-second apart (~300,000 km), and \( v_{\text{sound}} = 10^6 \, \text{m/s} \) (much faster than Earth’s air, but still sub-light), the sound would arrive ~300 seconds (5 minutes) after the light. Only if \( v_{\text{sound}} = c \) (like light itself) would the blast be seen and heard at the same moment. However, this would conflate light and sound into a single phenomenon, which is counterintuitive to our understanding of waves.

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### **Physics of Aether-Sonis**  
- **Medium for sound**: Aether-sonis acts like a cosmic fluid, enabling longitudinal pressure waves (sound) to propagate through the vacuum. Unlike light (an electromagnetic wave), sound requires a medium, which aether-sonis provides.  
- **Speed of sound**: Determined by aether-sonis’s elasticity and density. If it behaves like a massless scalar field, \( v_{\text{sound}} \) could approach \( c \), but relativity would cap it below \( c \).  
- **Energy transfer**: The explosion’s mechanical energy generates vibrations in aether-sonis. These propagate outward, striking the nearby ship’s hull and converting into structural vibrations, which then couple to the cockpit’s atmosphere as audible sound.

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### **Conclusion**  
The crew would witness a vivid visual explosion first, followed by a delayed, thunderous sound. The delay时长 depends on the distance and \( v_{\text{sound}} \), but they would not experience both senses simultaneously unless aether-sonis allows sound to travel at light speed—a scenario that would redefine wave physics in this universe. This trope adds dramatic tension, blending the cosmic scale of space with visceral auditory feedback.