In case you don't remember this post, here is my rule of thumb to decide the maximum number of authors of an academic paper: "The list of authors should not be longer than the abstract."
A physics paper with 5,154 authors has — as far as anyone knows — broken the record for the largest number of contributors to a single research article. Only the first nine pages in the 33-page article, published on 14 May in Physical Review Letters, describe the research itself — including references. The other 24 pages list the authors and their institutions.
Clearly, I don't have much influence in the academic world. I hope at least they have included the authors' names in the correct order.
Credit: Jorge Cham/PhD Comics