This class will focus on the more practical aspects of why we study the Sun, namely its impact on the Earth. Topics to be covered at a rudimentary level will include solar variability and the physics behind it (solar dynamo, solar cycles for long-term variability, sunspots, solar flares and coronal mass ejections for short-term variability), observational aspects of detecting this variability (total solar irradiance measurements, multi-wavelength space and ground based observations), the Earth’s response to this variability (“mini ice-ages”, magnetospheric storms, atmospheric ablation, etc.) and finally the broader context (manned exploration of the moon and Mars, our understanding of other stars, search for life on extra-solar planets).