Are you mixing gravity waves and gravitational waves? Gravity waves are any waves in media in which gravity acts as restoring force, like waves in ocean, or waves between layers with different densities in atmosphere, or, AFAIU, whole atmosphere (think of atmosphere as a big shallow pool, with air sloshing around in the pool instead of some liquid).<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Gravity_wave" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Gravity_wave</a>