many great physicists studied the mechanical properties of the luminiferous ether

An example of a historical scientific idea that today would be considered an alternative conception,

"There are also many phantom problems which are indubitably doomed to remain such forever. One of these, for instance, is the problem which used to keep many a great physicist busy for many years: The study of the mechanical properties of the luminiferous ether. The meaninglessness of this problem follows from its basic premise, which postulates that light vibrations are of a mechanical nature. This premise is erroneous, and must remain so forever."

Plank, M. (1947/1949). Phantom problems in science (F. Gaynor, Trans.). In Scientific Autobiography and other papers (pp. 52-79). Philosophical Library.

Read about ideas of the ether

Author: Keith

Former school and college science teacher, teacher educator, research supervisor, and research methods lecturer. Emeritus Professor of Science Education at the University of Cambridge.