A very well ballanced introduction to a fringe, but interesting approach to explaining the origin of gravity. While the discussed paper has not yet passed the peer review, it should be mentioned that the papers introducing the underlying theory were published in respected journals. Commendably, the article quotes not only one of the authors of the idea, but also some of its defenders and opponents. The problem being solved is reviewed a bit too briefly. However, the core ideas behind the proposed resolution are explained quite well, even if some details are, to borrow the article's term, “wobbly”.

A rather nice short summary of loop quantum gravity and superstring theory, nontechnical and yet giving the right overall idea. I especially appreciate the carefully written validation section, although it does not stress how technically challenging the testing of either theory is. To be more ballanced, the article should at least in passing mention that other approaches to quantum gravity/cosmology exist (even if loops and superstrings are arguably the most popular ones).

The article reports on a Nature paper, it is easy to follow and fairly accurate. All in all, a very nice work.

Unfortunately, the intro seems a little unclear. It haphazardly throws together all the famous quantum paradoxes. The mention of Schrödinger's cat is especially out of place, as a thought experiment (never performed) that deals with quantum behaviour of macroscopic objects. I find it misleading to just name-check it and then proceed to discuss a real experiment with macroscopic quantum behaviour.