The solar mass (M☉) is a standard unit of mass in astronomy, equal to approximately 2×10 kg (2 nonillion kilograms in US short scale). It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. More precisely, the mass of. The value of the gravitational constant was first derived from measurements that were made by in 1798 with a. The value he obtained differs by only 1% from the modern value, but was not as precise. The The mass of the Sun cannot be measured directly, and is instead calculated from other measurable factors, using the equation for the of a small body orbiting a central mass. Based on the length of the year, the distance from Earth to the Sun (an One solar mass, M☉, can be converted to related units: • 27068510 ML ()• 332946 ME ()• 1047.35 MJ ()It is also frequently useful in The Sun is losing mass because of occurring within its core, leading to the emission of, neutrinos and by the ejection of matter with the. It is expelling about (2–3)×10 M☉/year. The mass loss rate will increase when the Sun. • • • • •.