A distant planet has caught ancient radio signals from earth. They are visual images and audio of the chronicles of a exploratory ship and it's crew.
Over 200 years before humans figured out long-term space travel...
Everyone is confused. -- AmberFox
Filtering things out of the Hydrogen Line is an interesting task. Though it is a band relatively free of interference, there is still signal fade as it disperses through deeper space. Those listening for the echoes of the big bang regularly have to filter out the newer signals using the Hydrogen Line in order to do their research. The Archivaas, ever hungry for the lost information of Pre-Shattering Earth, always want to know what this signal is, and whether or not it is within their interests.
The process behind that is far more complicated. Removing noise from a faded signal is just as complicated as extracting the signal from the noise in the first place. Once one removes the relative noises of the stars, ancient or young, whatever remains must be the signal... most of the time. Some signals interfere with others, and filtering those from each other is an interesting exercise, starting with matching one or more of those with known signal patterns.
After all of that complication, the end result is similar to that of a decayed artwork, where every sound or frame is almost unrecognisable from the original. It takes an immense amount of interpretive untangling to restore a lost transmission from that faded work. Thusly, the results are contested by many other experts who have had many other ideas. Artificial intelligences are used to make certain the result an Archivaas may have obtained to what the signal is most likely to be. On this one, they agreed.