The sun is losing millions of tonnes a second
Sunlight is mass. Fusion converts about four million tonnes of the sun into energy every second, and a solar wind carries still more away.
Established2 min read
The solar luminosity is about 3.8 × 10²⁶ watts. Divide by c² and the mass equivalent is roughly 4.3 million tonnes each second. That is the hydrogen fused into helium, with the difference leaving as photons and neutrinos.
The solar wind removes on the order of another million tonnes a second of actual particles. Neither loss will shut the sun off soon. Over a ten-billion-year main sequence the fraction burned is a few percent of the mass. The rate is the shocking part, not the prognosis.
Caveats
- The fusion figure is the mass-energy of the radiation, not a stream of rocks leaving the surface.
- Solar-wind estimates vary with the cycle of activity.
Sources
- 1Bahcall J. N.. Neutrino Astrophysics. Cambridge University Press, 1989.