The past ten years have seen a tremendous increase in the number of Type Ia
supernovae discovered and in the quality of the basic data presented. The
cosmological results based on distances to Type Ia events have been
spectacular, leading to statistically accurate values of the Hubble constant,
Omega_M, and Omega_Lambda. However, in spite of the recent advances, a number
of mysteries continue to remain in our understanding of these events. In this
short review, I will concentrate on unresolved problems and curious
correlations in the data on Type Ia SNe, whose resolution may lead to a deeper
understanding of the physical mechanism of the Type Ia supernova explosions.Comment: 10 pages, aipproc LaTeX, two eps figures, to be published in "Cosmic
Explosions! The Proceedings of the Tenth Maryland Conference on
Astrophysics," eds, Steven S. Holt and William W. Zhang, AI
