Obviously some things about the Sun's relationship to Earth are known - if we get too close or too far away all life disappears. But other aspects, like the activity of the Sun related to heating and cooling, are less clear.
It has long been known that the Sun's activity waxes and wanes over an 11-year cycle and that as its activity wanes, the overall amount of radiation reaching the Earth decreases. A new study looked at the Sun's activity over the years 2004-2007, when it was in a declining part of its 11-year activity cycle.