>Since most planets don’t have an atmosphere

I wouldn't be too sure about that, even in our own solar system that's not true.
Jupiter, Neptune, Saturn, Uranus, Venus, Earth, Mars all have atmospheres. Only Mercury really has very little

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>no sound would travel unless the sound originated on the surface or within the planet

And it does. NASA's InSight lander is specifically designed to study seismic waves on Mars for example. Also, if a planet has an atmosphere, it has winds ofc

Regardless, sound waves still exist if you can't personally hear them, I think that's the main point