Gregory Benford is a professor of physics at the University of California at Irvine, and is also a science fiction author who has written more than a dozen books. We can therefore take the authenticity of the science in his book for granted, and the large number of novels to his credit ought to mean that he is able to embed the science in a convincing fictional setting. Unfortunately I didn't really feel that he entirely succeeded in this.
The story concerns a physicist who is conducting an experiment involving uranium atoms in the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, in which something goes wrong. There is an explosion, which results in the formation of a sphere (the Cosm of the title) that is a window on another universe, produced in the moment of the explosion. So much for the science. The physicist, who is a junior professor at Benford's own university, is a black woman, a fact which allows Benford to bring in a good deal of political commentary about colour and feminism. There is also a love interest: the physicist, Alicia, falls in love with the theoretician who helps her to understand the outcome of her experiment. And there is a counterplot, concerned with Brookhaven's attempts to get back the Cosm, which Alicia has removed from the wreckage of the explosion. None of this was particularly interesting for me and I found myself skipping a lot of it.
The physics and astrophysics of the Cosm itself are the most interesting part of the book but we don't really get enough of them; no doubt they were difficult to fictionalize, but the danger in a book of this kind is that the "human interest" material will look like padding. I don't think Benford has entirely avoided the danger. I was left with the feeling that he had tried to squeeze too much into the book--more, perhaps, than it could be comfortably hold. In a postscript he says that he wanted to show how scientists really are when they are at work, but for me this wasn't wholly successful. The Cosm itself is a fascinating idea but I'm not convinced that it lends itself easily to fictional treatment. I think that the book, judged as fiction rather than as highly speculative science, must be counted an interesting failure.