What Exactly Is Spacetime?




If we compare the definition of spacetime to the definition space, we see a stark contrast.  Wiki defines space as, “the boundless three-dimensional extent in which objects and events have relative position and direction.” There is no mention of “abstract” or “model” in that definition of space.








Reified model of spacetime






Given that wiki defines spacetime as a pure mathematical abstraction, the bending of a mathematical abstraction cannot impart real force on a real object.  It is instructive to note that the search for gravitational waves turned up nothing for decades.

The LIGO gravitational wave observatory never detected a gravitational wave up to 2016. LIGO’s fourth science run [S4] and GEO600, which were in operation together, did not detect any gravitational waves. LIGO’s fifth science run [S5], which had all three interferometers running continuously in triple-coincidence for an entire year, did not yield any gravitational wave candidates.

Now suddenly, the LIGO team claims to have discovered gravitational waves.  As the NYT article points out, different scientists made the same claim back in 1969, and again in 1974, and again in 2014.  Each time the claims were later overturned.  Supposedly the event they detected this time was “50 times greater than the output of all the stars in the universe combined.”  – Does that sound plausible to you?  Recently scientists concluded that there are over a trillion galaxies in the observable universe, each containing an average of 100 billion stars.

All that power condensed into a tiny point in space, but we couldn’t see it because “black holes.”  Yeah, and I have a bridge in Alaska I’d like to sell you.  While I have no doubt that the LIGO team detected some signal in their interferometers, just what exactly caused that signal is entirely up for debate. Dr. Hilton Ratcliffe provides an excellent skeptical overview of the results here.   Thornhill also provides some excellent skepticism here:


Defining gravity as bending spacetime creates other intractable problems. For example, quantum mechanics, which deals with objects on the atomic scale, has absolutely no working theory of gravity. In other words, scientists have no idea what actually causes gravity.



