The solar wind carries away about 1.6 million tonnes of mass every second, or 1.6 × 109 kg/s. That's a lot of material, for sure, and it adds up over long periods of time. Every 150 million years, the Sun loses roughly the mass of Earth due to the solar wind, or about 30 Earth masses over the entire lifetime of the Sun so far.
From fusion, however, the Sun loses even more mass than that. The Sun's power output is a relatively consistent 4 × 10-26 W, which means it converts approximately 4 million tonnes of mass into energy each second. From fusion, then, the Sun loses about 250% as much mass, each second, as gets carried away from the solar wind. Over the course of its 4.5 billion year lifetime, the Sun has lost about 95 Earth masses due to fusion: approximately the mass of Saturn.
The Sun, shown here, generates its energy by fusing hydrogen into helium in its core, losing small... [+] NASA / SOLAR DYNAMICS OBSERVATORY (SDO)
The evolution of the Sun's luminosity (red line) over time. The big increase is due to the core... [+] WIKIMEDIA COMMONS USER RJHALL, BASED ON RIBAS, IGNASI (FEBRUARY 2010) SOLAR AND STELLAR VARIABILITY: IMPACT ON EARTH AND PLANETS, PROCEEDINGS OF THE INTERNATIONAL ASTRONOMICAL UNION, IAU SYMPOSIUM, VOLUME 264, PP. 3-18
This Hertzsprung-Russell Diagram follows stars and our Sun as they move through their life's phases. Our Sun was born in a giant molecular cloud like the Pillars of Creation (A), moves through adolescence and middle age (B) on the main sequence, and it finally moves into Red giant phase (C,D, E,) as it swallows the Earth in its extended shell, then slowly drifts apart as a beautiful planetary nebula (F), leaving just a White dwarf in the center of the now slowly dissipating nebula (G). Hartmann352
As time goes on, the amount of mass lost by the Sun will increase, particularly as it enters the red giant phase of its life. But even at this relatively steady rate, the growth of helium in the Sun's core means that we will heat up here on planet Earth. After about 1-to-2 billion years, the Sun will be burning hot enough that Earth's oceans will boil away entirely, making liquid water impossible on the surface of our planet. As the Sun gets lighter and lighter, it will counterintuitively get hotter and hotter. Our planet has already used up approximately three-quarters of the time we have where Earth is habitable. As the Sun continues to lose mass, humanity and all life on Earth approaches its inevitable fate. Let's make these last billion-or-so years count.
A 10% increase in the sun's brightness will trigger the evaporation of our oceans and as the oceans evaporate, more and more water will saturate the atmosphere. This water vapor will act as a greenhouse gas, trapping even more heat and causing more and more of the oceans to evaporate, until the ground is mostly dry and the atmosphere holds the water, but at an extremely high temperature.
As the atmosphere is saturated with water, the water held in the highest parts of our atmosphere will be bombarded by high energy light from our sun, which will split apart the molecules and allow the water to escape as hydrogen and oxygen, eventually drying the Earth of water.
Stars don't stay the same throughout their life, and the Sun is no exception. Here's what's going on.
Our sun, jolly old Mr. Sun, Sol, will never go nova or supernova, it doesn't have the mass for those kinds of explosions. But, as the sun leaves the main sequence as its mass decreases and its volume and heat increase, it will, after sufficient time, eventually make life on Earth and Mars untenable. Man, in order to survive, must have reached the stars and have become interstellar voyagers and traders. If we fail to move beyond our solar system into the stellar stream of the Carina-Sagittarius Arm, mankind will be just another failed civilization in the Milky Way Galaxy, where the grave of our solar system will be marked by a beautiful planetary nebula.