Now that we’ve flipped the calendar page to January, it’s a chance to celebrate that 2015 has been declared the International Year of Light and Light-based Technologies (IYL 2015) by the United Nations. We don’t take this opportunity – pardon the pun – lightly.  This is for several reasons. First, our jobs revolve around light.  We work for NASA’s Chandra X-ray Observatory, which is a telescope in space that observes X-rays from the Universe. X-rays are a kind of light. In fact, there are many different kinds of light, but only one that the human eye can detect naturally (called optical, or “visible,” light).