Analysis of information sources in references of the Wikipedia article "First observation of gravitational waves" in English language version.
With gravitational waves, we do expect eventually to see the Big Bang itself.
We will be able to measure the rate the universe is expanding, or how much dark energy there is in the universe to extraordinary precision
... Now assume that we are 2 m (~6.5 ft) tall and floating outside the black holes at a distance equal to the Earth's distance to the Sun. I estimate that you would feel alternately squished and stretched by about 165 nm (your height changes by more than this through the course of the day due to your vertebrae compressing while you are upright) ...
We will be able to measure the rate the universe is expanding, or how much dark energy there is in the universe to extraordinary precision