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 Friedmann-Lemaître-Robertson-Walker metric: by dividing the equation above with formula_10 and identifying formula_11 (the energy density), we get one of the FLRW equations of motions. In the comoving coordinates, formula_12 is equal to the mass density formula_13. For radiation, formula_14 whereas for matter formula_15 thus formula_12 is proportional to formula_17 For matter formula_18 thus formula_12 is proportional to formula_20 This can be understood as follows: For matter, the energy density is equal (in our approximation) to the rest mass density. This is inversely proportional to the volume, and is therefore proportional to formula_20. For radiation, the energy density depends on