The Sun loses mass at a rate of about 5.5 million tons per second which is about 174 trillion tons per year!  This loss of mass occurs for two reasons: (1) protons and electrons that boil off the surface of the Sun in what is referred to as the “solar wind” and (2) due to the nuclear fusion that produces the heat and light we see and feel.

While 174 trillion tons is a lot of mass, the Sun’s total mass is 4.385 nonillion pounds (a nonillion is a one with 30 zeros behind it). The Sun is so massive that it comprises 99.86% of all the mass in our solar system.

Over the next 5 billion years (the Sun’s approximate life expectancy) the Sun will only lose 0.034% of its mass as the 174 trillion tons, while a large number, is still a very small number as compared to 4.385 nonillion pounds.

The Sun’s loss of mass reduces its gravitational pull and results in the Earth’s average orbit increasing by 1.6 centimeters per year.