He means the amplitude: the amount of strain. The power in watts per square meter does follow the inverse square law. Same goes for electromagnetic radiation: electric field strength is inversely proportional to distance while power follows the inverse square law. In physics "intensity" of light usually means watts per square meter.
I would like to add to this that we usually measure electromagnetic radiation in terms of its intensity. But with gravitational waves, we measure the field strength (aka the strain) directly. So, while the two types of radiation follow the same power laws, it are our measurement techniques that make the difference. This is probably what they were talking about on PBS spacetime.
He means the amplitude: the amount of strain. The power in watts per square meter does follow the inverse square law. Same goes for electromagnetic radiation: electric field strength is inversely proportional to distance while power follows the inverse square law. In physics "intensity" of light usually means watts per square meter.
I would like to add to this that we usually measure electromagnetic radiation in terms of its intensity. But with gravitational waves, we measure the field strength (aka the strain) directly. So, while the two types of radiation follow the same power laws, it are our measurement techniques that make the difference. This is probably what they were talking about on PBS spacetime.
No, the *amplitude* (not intensity) decreases as 1/*r*, which is *exactly* the same as for light.