Vera Rubin and Fritz Zwicky both discovered dark matter using 2 different approaches. There are dozens of theories for dark energy each with subsets and corollaries. So far everyone is still in the running for a major discovery. What is sought is an eloquent and simple explanation but I think several 'special circumstances' will confound the process for decades more. All cosmologists, mathematical physicists and astrophysicists are openly hoping they will be the 'one'.