Earth is heating up lately, but so are Mars, Pluto and other worlds in our solar system, leading some scientists to speculate that a change in the sun's activity is the common thread linking all these baking events. Others argue that such claims are misleading and create the false impression that rapid global warming, such as Earth is experiencing, is a natural phenomenon. While evidence suggests fluctuations in solar activity can affect climate on Earth, and that it has done so in the past, the majority of climate scientists and astrophysicists agree that the sun is not to blame for...