# RE: Gravity waves (was seti@home is SORTA WORKING)

Rob Harris Cen-IT (Rob.Harris@bournemouth.gov.uk)
Thu, 15 Jul 1999 13:10:51 +0100

> On Mon, 12 Jul 1999 13:23:50 +0100 Rob Harris Cen-IT
> <Rob.Harris@bournemouth.gov.uk> writes:
>
> [Ron Kean]
> >> Gravity waves are a different phenomenon than gravitational waves.
> >> Gravity waves are waves
> >> consisting of the motion of fluid matter in a gravitational field.
> >The
> >> ripples on the surface of a pond are called gravity waves.
> >>
>
>
> > Are you certain about this? I don't remember any of this when
> >I did
> >A level Physics. I would call waves in water exactly that: water
> >waves,
> >sound = air waves, light = wave in some kind of electromagnetic ether
> >(spacetime?) - I don't know this part at all - anyone got the info?
> >
> > Rob.
> >
> >
>
>
> Certainly surface waves in water can be called water waves, and usually
> are (in a non-technical context), without any misunderstanding. But
> sound travelling through water can also be called 'waves in water', so
> the term 'water waves' is technically imprecise, or ambiguous. So the
> waves on the surface of a pond are better called 'gravity waves along a
> water-air fluid interface', or just 'gravity waves' for short, since
> their propagation depends on the interaction between the earth's gravity
> (which is perpendicular to the surface of the pond) and the density,
> viscosity, and surface tension of the water. Without gravity those waves
> won't happen. That's why they're called 'gravity waves', as a technical
> term.
>
So, the name of the wave comes from the source of it's energy - in this case gravity. Not, as I thought before, the medium in which the wave exists...... Is this correct?
BTW - cheers for the fine explanation !

Rob.

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