Robert Boyle Robert Boyle Robert Boyle (; 25 January 1627 – 31 December 1691) was an Anglo-Irish natural philosopher, chemist, physicist, and inventor. Boyle is largely regarded today as the first modern chemist, and therefore one of the founders of modern chemistry, and one of the pioneers of modern experimental scientific method. He is best known for Boyle's law, which describes the inversely proportional relationship between the absolute pressure and volume of a gas, if the temperature is kept constant within a closed system. Among his works, "The Sceptical Chymist" is seen as a cornerstone book in the field of chemistry. He
Thermodynamics of the universe the temperature formula_22 as well, and is therefore proportional to formula_23. As the universe expands it cools down, so formula_22 depends on formula_9 as well. In fact, since the energy of a relativistic particle is inversely proportional to its wavelength, which is proportional to formula_9, the energy density of the radiation must be proportional to formula_17. From this discussion it is also obvious that the temperature of radiation is inversely proportional to the scale factor formula_9. Plugging this information to the Friedmann-Lemaître-Robertson-Walker equations of motion and neglecting both the cosmological constant formula_29 and the curvature parameter formula_30, which is justified