[Bloody Sam Roberts]

This was all predicted by Gene Roddenberry (and Harlan Ellison) years ago in the Emmy nominated Star Trek episode, "The City on the Edge of Forever".

The Enterprise discovered the existence of The Guardian time portal device mainly because of extremely intense gravity waves emmanating from a distant planet.

Another case of life imitating art.

[GOPJ]

"The Hunt for Zero Point" (inside the classified world of antigravity technology) by Nick Cook, former aviation editor at Jane's Defence Weekly. Worth the time...

[Caesar Soze]

Uh, no. Gravity waves were predicted in 1915. COTEOF was written in the late 60s. And some might question whether the "time waves" encountered by Enterprise are the same as the "gravity waves" we know today -- especially since there were no obvious changes in the planet's gravitational field once the landing party beamed down.

[RightWhale]

we may well not know what it is we're going to observe

This might be hard to believe, especially in the case of Harlan Ellison, but gravity scientists might see something entirely unsuspected. It could happen, and seems to happen often when new instruments of new design are used for the first time to examine things never seen before. Scientists live for this.