Gravity gets you down…hah, hah. It's an old joke. Sorry. But, what is gravity? It's not the mysterious, invisible force you thought it was. It is, at least according to a rather well-known, but nevertheless, hundred-year-old theory, the distortion of the spacetime continuum by objects with mass.

You've probably all seen the black rubber sheet with the grid drawn on it and the big ball plonked in the middle curving the polyterpene fabric and a marble, say, "orbiting" the big mass because of that curvature. But, that doesn't explain anything. I always thought Michelson and Morley had shown that space was not a luminiferous ethereal substance so how can spacetime be a fabric, and how can it curve in anything but a theoretical, mathematical framework.

Moreover, given this week's big announcement on the discovery of gravitational waves generated by the collision of two black holes 1.3 billion lightyears from Earth, how can this mathematical construct of which Professor Einstein wrote a century ago have ripples in it as if the fabric were disturbed like a pond on which two ducks chasing breadcrumbs collide?

Now, as you will more than likely have gathered, I am not a physicist. I did a bit of physics at university, taking great inspiration from the fact that Paul Davies was one of my profs, and indeed, it was he that explained to my lowly chemist's brain the ins and outs of relativity, both general and special, and I did, for a short time almost understand it, vaguely. Einstein, after all, was very much standing on the shoulder of giants just as Newton had so there was a proverbial breadcrumb trail to follow and oh so many collusions. Without those earlier ethereal experiments and Maxwell's demonic equations there would have been no foundations on which old Bert could build his theories and E would never have been revealed to equal "em-see-squared."

Nevertheless, no matter how hard I think about this stuff, I fundamentally lack the mathematical prowess to truly understand it, especially when they throw in expansion and contraction, dark energy and dark matter and the fact that the universe is probably 90 billion lightyears across because of Hubble and mostly way beyond even the theoretical limits of observation.

The diagrams and wonderful graphics of undulating waves and rippling tubes and merging black holes that have been scattered across the media universe since 11th February are just so much spume on those waves, they are the frothy spindrift that might catch your eye as the sunlight glints from it and the tide turns. They do not tell me, or anyone else I know, as far as I can tell, what spacetime actually is and without understanding that it feels impossible to grasp gravity. Those diagrams and the supposed dummies guides to gravitational waves don't get to the crux of the matter. That rubber sheet with its white lined grid is just a model and not a very good one at that. It relies on an "external" gravity to explain why the big ball make an indentation in the fabric at all as it would not do so if it were in freefall or far from the Newtonian world of apple trees.

As a chemist, it's stuff I'm interested in. Something of substance, a material reality. If it's all just ephemeral equations, then how can I know it's real? It's important, despite this week's funding declarations about "national interest" in the US, we should seek the universal truths regardless of whether they will have any impact whatsoever on the everyday lives of citizens. We must be as curious as the proverbial cat in a box. Cosmology is unlikely to kill us. There is a certain gravity to this situation, but I am still none the wiser as to what that actually is…

David Bradley blogs at Sciencebase Science Blog and tweets @sciencebase, he has recorded a Gravity Suite to celebrate the discovery of gravitational waves, which you can listen to via his blog.