Thus, Belczynski's team concludes that if Cygnus X-1 is representative of future
black hole - neutron star binaries, observers seeking to detect gravitational waves should not expect to see them from
mergers of such systems.
More - stringent tests will be possible if and when LIGO detects
black -
hole mergers that are larger than this one, or that occur closer to Earth than the Event's estimated distance of 1.3 billion light years, and
thus give «louder» waves that stay above the noise for longer.