We're so used to seeing the sun as a life-giving force that we often forget that it's also downright terrifying. This 1997 photograph taken by the space-based Solar & Heliospheric Observatory shows a vast "solar prominence" (lower left) erupting from the sun's surface. These cataclysmic events, with tongues and loops of superheated gas lifting off to heights of hundreds of thousands of miles, sometimes remaining suspended there for months at a time, are eerily gorgeous reminders that, while the sun is a source of a nice tan, it's also an unfathomably large and volatile nuclear fusion reactor, releasing each second more energy than human beings have used in the last 10,000 years.