"We cannot hear the explosions on other planets." Why?

Explanation

To understand why we cannot hear explosions on other planets, we can break down the explanation into several key steps:

### Step-by-Step Solution:

1. **Understanding Sound Propagation**:
- Sound is a mechanical wave that requires a medium (solid, liquid, or gas) to travel. This medium must have particles that can vibrate and transmit the sound energy.

2. **Nature of Space**:
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