Our sun is gradually shrinking at a steady rate. It is occurring fast enough that, as little as 50,000 years ago, the sun would have been so large that our oceans would boil. 2 - Solar neutrinos. The sun is emitting hardly any neutrinos. 3 - Comets.
Comets circle the sun and are assumed to be as old as our solar system.
Since they are continually disintegrating, and a number are known to have broken up, evidently all of them self-destruct within a relatively short time period. 4 - Comet water. Comets are primarily composed of water. 5 - Solar wind. The sun's radiation blows very small particles in space outward.