[ISL]

You are absolutely correct. I'd somehow parsed the Mars number as in miles, rather than meters. Some part of my brain was surprised, but didn't pull the fire alarm.

On the LIGO question: Two GPS-synchronized cows, standing near the end-masses, that mooed in the appropriate chirp (correcting amplitude for polarization) would make people nervous enough to do a few calculations and, out of an abundance of caution, put up a fence. I expect the gravitational effect from any mooing (it's a tiny quadrupolar deformation of the cow) to be extremely small.

In practice, even the end-station buildings are large enough to keep cow-moos from happening close-enough to bother the instrument gravitationally. Furthermore, there are no cows at Hanford, and I doubt that there are any near Livingston.

[gus_massa]

Just to be 100% sure, I don't expect LIGO to detect the sound waves of the moowing cow, or the deformation of the cows while moowing. But can it detect the movement of a cow nearby?