# What difference does the wavelength and/or frequency of a gravitational wave make? On the detector, for instance?

When they talk about the arms of LIGO or Virgo stretching by a thousandth of the width of a proton, they always emphasize that this is the wave's amplitude, not wavelength...

The wavelengths are apparently quite long, with correspondingly low frequencies... Articles usually explain what this means in terms of what is going on out there in space, with the actual black holes and such, but...

What difference does the wavelength and frequency make for us here on Earth? For the detectors?

The detectors are said to only be capable of detecting gravitational waves within a certain range of wavelengths.... Why?

• This question received very little answers, here's why I think why that is. You ask several questions. The first ones (about frequency/wavelength) are very searcheable; I recommend the wikipedia article for that. Asking questions that are very searcheable discourages answers. However, your last question is interesting. With the current detectors, why is there an optimum frequency range? I didn't find information about that. My best guess is that in noise suppression there is a trade-off. Interestingly, the future GW-detector-in-space is described as having a very wide frequency sentitivity – Cleonis Aug 14 '20 at 4:46

As the observed frequencies are small enough, we observe, at best, a "coherent" states of gravitons, i.e. when their number is huge. No way to observe a single graviton with the energy $$\hbar \omega$$.