: Georgia Mansell/LIGO Hanford Observatory)

In the quest to detect gravitational waves, there are a number of obstacles that — no matter how hard we try — continue to stand in our way. Since 2015, with the advent of first the advanced LIGO detectors and then later, the Virgo detector, humanity has from a particular set of sources: merging stellar-mass black holes, merging neutron stars, and (perhaps) merging black hole-neutron star pairs. More recently, a different technique, leveraging pulsar timing, has or the sum of all background gravitational wave signals with a much longer timing period.

Nevertheless, there are still limits to what we can do with current technology.

• We’re frequency-limited, meaning that we can only detect sources from systems that strongly emit gravitational waves with a specific, narrow range of orbital periods. (This is why LIGO is only sensitive to relatively low-mass sources.)
• We’re limited by the seismic noise floor of Earth, as subterranean vibrations, even due to the…