Are rings not only important to this episode but a call back to the previous one - The Bells of Saint John? After all, bells ring. A true ring has no discernible beginning, middle or end. It is not linear; everything within it simply exists everywhere all the time. The Akhaten system is a series of rings inhabited by many different races. There are seven planets, which is fitting since there are seven musical notes and the Akhaten culture centers on perpetuating a song that lulls their god to sleep. Voices ring out in song. Rings often appear in works of mythology and fairy tales. There is of course, The Lord of the Rings and Wagners Ring Cycle both of which feature magic rings that grant dominion over the world. Clara uses a ring that was given to her by her mother to pay for the use of what is basically a space jet ski when she and the Doctor need to rescue Merry. That was definitely one of the more unfortunate choices either the author and/or the production team made. Is Claras ring significant? The Doctor, with a rather feeble explanation, returned it to her at the end of the episode.