But, they are looking! If they do find too many more structures or even ones younger, they say that we may have to do some re-thinking of our existence and how we came about.
I never heard about this problem before and found it fascinating. Even I can understand it! To me this kind of research /exploration is very cool. I am just astonished, that something like this can be found and verified to exist.
Galaxy clusters are the universe's largest collections of items held together by gravity, and scientists hope the discovery of one at such an early stage will help them discover more about how the universe evolved.
The discovery is on the cusp of when scientists think galaxy clusters can exist based on how long it would take them to assemble, said Dr Ben Maughan, lecturer in astrophysics at the University of Bristol.
"It is certainly the earliest example by a long way and it is pushing the limit of when we expect to see them. We do not expect to find many older than this, but you can never say never.
"Our models tell us that in the period of the universe we are looking at, the number of galaxy clusters we should be able to find is about one. ( me )
"If we were to find several tens of galaxy clusters at that distance that would be a matter of concern because in our current models the universe can not produce masses of galaxy clusters at such an early point."
Stefano Andreon, of the National Institute for Astrophysics in Milan, added: "This object is close to the distance limit expected for a galaxy cluster. We don't think gravity can work fast enough to make galaxy clusters much earlier."
I wonder if the models are correct or if there will one day be cause for "concern"?