What are the implications of the study of the supernovas that show the universe is increasing its rate of expansion? Why do scientists oppose the idea of an open universe?
Current knowledge indicates an expanding universe. NO references were found that indicate any scientists oppose the idea.
"an expanding or contracting universe is inevitable given general relativity"
Implications may be a more rapid approach to the "heat death" of the universe. Certainly, distances between galaxies will increase, but until we really are capable of inter-stellar travel in reasonable times, that may not be much of a practical concern.
It is true that some scientists continue to explore other options. I do not take that as a specific opposition to an open universe theory, but a parallel course of investigation. The major obstacle to a closed universe theory is the absence (so far) of the necessary mass or energy needed to fulfill mathematics of contraction.
Good background material: