Just wondering about it. I had never thought about it before, but it sounds very plausible. This word was first used in astrological terms to refer to an unfavorable aspect of a star. At one time, all events in human existence were attributed to the motions of the planets. Today, of course, we don't think of the stars at all when we use the word, but, as you suggest, Stephanie, the aster portion of the word reminds us of its roots.
Standard scholarship holds that English took goblin from the French gobelin .
The problem with this is that, while Middle English had the word goblin as early as 1320, there is no record of the French word gobelin until the 16th century. Interestingly, a 12th century cleric called Ordericus Vitalis mentions Gobelinus as the name of a spirit which haunted the neighbourhood of vreux. If so, it is related to the German kobold , and hence to the name of the metal cobalt . My several etymology books were no help in finding the origin of the word. Blah as an actual word originated in the U.S. as an imitation of the sound of meaningless talk.