In many stories, light plays the role of messenger. The star of Bethlehem acted both as a beacon and a promise. A flashing light on the shore was a signal for smugglers to slip into the cove with their contraband. The red light on the control panel warned the aircraft pilot of mechanical failure.

 

Astronomers gather light in their giant telescopes to sift out the information it contains. Stars imprint their spectral fingerprints on the light they emit. Nebulae leave their stamp on starlight as it passes through the wispy gas and dust clouds. Even gravity exerts its influence on light, bending it along with space and time itself.

 

Since everything in the Universe is so spread out, distances so large, and objects so far from Earth, astronomers rely on electromagnetic radiation in its various forms (light being just a small subset) to carry messages from afar. Decoding those messages requires intimate knowledge of both matter and energy and how they interact. Experiments in laboratories uncover the laws that govern those interactions, and provide the keys to unlock the secrets hidden in a beam of starlight.

 

This week, open the magic book that only the initiates can read. Learn how to trace the spiderwebs of spectral lines revealed by the crystal prism as it stretches the gleam of Vega or Aldebaran. Let the vision of the hot, blue star in black space or the bloated red giant engulfing its planets form in your mind. Don your pointed cap with stars and crescent moons: it is time to witness the power of science.