From 1899 to 1903 De Pretto began to study the emerging field of
nuclear physics and its relationship to
astronomy. He focused on the theory of
aether, a hypothetical substance that at that time was believed to fill all space. As a result of his research on November 29, 1903, De Pretto published a 62-page paper in the
Atti del Reale Istituto Veneto di Scienze, Lettere ed Arti, vol LXIII (
Proceedings of the Royal Veneto Institute of Science, Letters and Arts) entitled "''Ipotesi dell'Etere nella Vita dell'Universo
" ("Hypothesis of
Aether in the Life of the Universe''"). The paper was endorsed by the famous astronomer
Giovanni Schiaparelli. De Pretto's paper was later included in the proceedings of an Italian scientific institute The Royal Veneto Institute of Science. This theory was similar to
Samuel Tolver Preston's 1875 hypothesis that matter and energy might be interchangeable. De Pretto's theory was based on his
hypothesis that a mass traveling at velocity
v has the
potential energy By theorizing the "vibration of the ether", De Pretto asserted that mass is vibrating energy and that mass and energy are therefore interchangeable. He then speculated that ordinary matter may be considered to be vibrating at the
speed of light c. According to De Pretto, :
The matter of any body contains within it a sum of energy represented by the entire mass of the body[... ] Nobody will easily admit that, stored in a latent state, in any kilogram of matter, completely hidden to all our investigations, hides such a sum of energy, equivalent to the amount that can be extracted from [burning] millions and millions of kilograms of coal." ½mv² versus mc² De Pretto used the expression mv^2 for the "
vis viva" and the energy stored within matter, where he identified
v with the
speed of light. According to Italian mathematician
Umberto Bartocci, his formula precedes by two years, and is in agreement with
Albert Einstein's later formula E=mc^2 for
mass–energy equivalence, which was derived by Einstein as a consequence of
special relativity. According to Bartocci, Einstein may have learned of de Pretto's work through his Swiss-Italian friend
Michele Besso.
Radioactive decay De Pretto's paper discussed the
radioactive decay of
uranium and
thorium and was the first to conclude that this decay was energy transformation from mass into energy. He also presented a hypothesis that the intense heat assumed to be in the centre of the
Earth (theory of central fire) was caused by the tremendous mass of the earth creating a massive radioactive core giving off heat and energy. ==Honours==