Fill in the Blanks Nature of StarsOnline version Some basic information about stars. by Rolf Hanimann 1 fusion helium positrons helium mass mass nuclear neutrinos defect emitting Joules less protons mc2 tons hydrogen Stars are a lot of energy . The source for most of this energy is the of into . In an extremely simplified manner we can state that in a reaction 4 fuse into a nuclei releasing 2 and 2 . The mass of the products is than the mass of the 4 protons . This is called and is converted into energy , using Einstein ? s famous formula E = . Therefore , our Sun is losing every second about 40'000 of radiating about 10 at the 26 of energy every second .