Fans of HBO's hit show Game of Thrones will quickly tell you that "Winter is coming." It's a mantra used on the show to predict extremely long, Ice Age-style winter seasons, sometimes lasting over 20 years. Could we ever see these kinds of extreme, extended winters in real life? Veronica visited the Exploratorium in San Francisco and chatted with planetary physicist Paul Doherty to figure out if our own planet could endure such bitter seasons. Is winter coming for us? You may be surprised.