Subspace morphology is a division of science that relates to the altering of subspace to form a metaphasic shield.
During the late 24th century, Dr. T'Pan was considered the leader in the field of subspace morphology.
Until 2369, it was believed impossible to alter subspace in a way which would protect a ship from the heat and radiation of entering a star. However, Ferengi Doctor Reyga was able to develop such a device, which unfortunately lead to his death. (TNG: "Suspicions")