Thomas Kuhn in the Structure of Scientific Revolutions writes (p. 89, Second Edition): "crisis simultaneously loosens the stereotypes and provides the incremental data necessary for a fundamental paradigm shift." So far, it seems dark energy does not fit into any of the existing paradigms (or any of several proposed ones). GR does not explain it. MOND has not explained it. QM has not explained it. Is the 1998 discovery of "dark energy" such a crisis?