I know I've had a fair few of these questions recently, but I just can't remember their titles!
So, this one kind of reminded me of 2001: A Space Odyssey. It has aliens that left a special artifact on the moon which broadcasts signals into space. Then, something happens that causes those signals to stop and people go to investigate, I think. It was also once mentioned that the aliens used special human technology to put the artifact there. Final detail: I'm pretty sure the object was in the shape of a pyramid or a triangular prism. 60% sure that this is Asimov, Bradbury, or one of the other Sci-Fi giants.