What a fascinating scenario! Let's dive into the experience of the pilots in the nearby ship.

As the enemy ship explodes, the blast releases a massive amount of energy in the form of heat, light, and kinetic energy. In the vacuum of space, without a medium to transmit sound waves, the explosion would normally be silent. However, with the introduction of aether-sonis, the situation changes dramatically.

The explosion creates a shockwave that propagates through the aether-sonis, generating a pressure wave that can be heard by the pilots in the nearby ship. Since aether-sonis is massless and invisible, it doesn't interact with light or other forms of electromagnetic radiation, so the pilots wouldn't see any visible effects of the aether-sonis itself. However, they would hear the explosion as a loud, sharp report, similar to a cracking or booming sound.

The sound of the explosion would be transmitted through the aether-sonis at a speed that is likely to be much faster than the speed of light, potentially even instantaneous. This is because aether-sonis is a fictional substance that can perfectly transmit vibrations, implying that it has a non-physical, perhaps quantum-like behavior. This would allow the sound wave to propagate across vast distances in a very short time, possibly even allowing the pilots to hear the explosion before they see the visual effects of the blast.

The visual effects of the explosion would still be delayed, as light travels at a finite speed (approximately 300,000 kilometers per second). The pilots would see a bright flash of light, followed by a rapidly expanding cloud of debris and gas. The delay between the sound and light would depend on the distance between the two ships. If the ships are relatively close, the delay would be minimal, and the pilots might experience the sound and light simultaneously. However, if the ships are farther apart, the pilots would hear the explosion before they see the visual effects, potentially by a significant margin.

To give you a better idea of the physics involved, let's consider a rough estimate of the speed of sound in aether-sonis. Assuming that aether-sonis has a similar density to air (which is a big assumption, given its massless nature), the speed of sound in aether-sonis could be on the order of 1,000-10,000 times the speed of light. This would mean that the sound wave from the explosion could travel across 1 AU (astronomical unit, approximately 150 million kilometers) in a matter of milliseconds, while the light from the explosion would take around 500 seconds (or about 8 minutes) to cover the same distance.

In conclusion, the pilots in the nearby ship would hear the explosion as a loud, sharp report, potentially before they see the visual effects of the blast. The experience would be similar to being in a terrestrial environment, where sound and light travel at different speeds, but with the added twist of the aether-sonis allowing for potentially instantaneous sound transmission across vast distances. The delay between the sound and light would depend on the distance between the ships, and the pilots would need to be aware of this effect to accurately interpret the sensory information they receive during the battle.