Nothing lasts forever, even atoms. Heavier elements decay into lighter elements, releasing energy as radiation. But thanks to this radiation, astronomers can get a glimpse into what’s going on inside distant start. Let’s take a look at the whole process of radioactive decay, the different events that happen, and how humans use this fundamental force of nature for our own needs.

Just when you think you understand it, light will do some amazing things. Just look at the discovery of lasers, and their use in almost every technology you can think of: from cutting, to transmitting information to, yes, astronomy. And nature has figured out its own version of laser technology, called the maser, which has kept astronomers puzzled and excited for years.