Jan. 8, 2013:
In the galactic scheme of things, the Sun is a remarkably constant star. While some stars exhibit dramatic pulsations, wildly yo-yoing in size and brightness, and sometimes even exploding, the luminosity of our own sun varies a measly 0.1% over the course of the 11-year solar cycle.
There is, however,,
Source: Solar Variability and Terrestrial Climate - NASA Science