PubMed accesses primarily the MEDLINE database of articles written about the life sciences but other sciences are represented too, even astrophysics. The first article turned up by searching black hole was “A possible macronova in the late afterglow of the long-short burst GRB 060614,” which is quite a long way from any biomedical phenomenon with which I am familiar. Scanning down the list of retrieved articles, there were the European Physical Journal, Physical Review Letters and lots more that medical doctors won’t see very often. An article in Physical Review Letters titled, “Search for gravitational waves associated with γ-ray bursts detected by the interplanetary network” had 898 authors, but that turned out to be a small team: “Search for quantum black hole production in high-invariant-mass lepton+jet final states using pp collisions at √s=8  TeV and the ATLAS detector” had 2908.

But there were medical articles in the list, so the metaphor black hole has crossed from astrophysics to medicine. In doing so, it has lost its real significance. An astrophysical black hole has a gravitational field so strong that even light cannot escape: surrounding space is sucked into it and exists no longer. Medical black holes are just empty. Neuroradiologists use the term for a particular lesion in multiple sclerosis, but there is no suggestion that the neighbouring neural tissue is pouring into it. A number of authors use it as a metaphor for lack of knowledge, or for something that is being ignored. It’s also used for something unpleasant looming, such as the coming staffing crisis in the NHS (an article written in 1988). Sometimes it is unclear what the metaphor means: why is incontinence caused by obstetric practice a “black hole of preventable morbidity?”

There is an inherent contradiction in the borrowing of another astrophysical term: big bang. Without the Big Bang—in capitals to differentiate it from metaphorical big bangs, and always supposing the theory is correct—nothing would exist at all. So it is exaggerating and unhelpful to apply it to events in immunology, how cancer metastasizes, the evolutionary development of the folding of proteins, catastrophic events involving large numbers of injured, or the reorganisations of the UK’s health service with changes of government.

Organisms have two basic reproductive strategies: semelparity, which means reproducing once in a lifetime; and iteroparity, reproducing more than once. Semelparity is known as “big bang,” because it is once in a lifetime and usually fatal, but the only thing that died at the Big Bang was the singularity. There is an article titled, “Towards a unifying theory of clinical research. Where is our big bang?” The full text is behind a pay wall, but I struggle to see how reference to the grand unifying theory in physics can help understand medicine, nor how medicine can have an analogous big bang.

All these singular, sudden, or extensive events have little in common with the Big Bang. But I got a special satisfaction from an article that described a development in haemofiltration (the publication of a trial supporting its advantage in intensive care) as a big bang. The authors could equally well have called it a quantum leap. Thus the much abused big bang—the largest event ever to have happened—is nothing more than the even more abused quantum leap—a quantum being the smallest measurable discrete change in a system.

Competing interests: I have read and understood BMJ policy on declaration of interests and declare that my only competing interest is my co-authorship of a book about medical English.

Neville Goodman is a retired consultant anaesthetist and a writer, and co-author of a book on medical English.