I love David Arnolds score here - he just layers and layers up the instruments and sounds and there are so many vignettes which come out of nowhere but seem just right. For instance a little violin solo at 0:55 is a real nice touch - he didn't need to compose it in but did and it just adds to the wonderful texture of this score.
The awe and the majestic of the discovery, the excitement and wonder, follow by those sad and weary notes at the end, perfectly foreshadowing the hardships to come.
That medalion has so much meaning to it, I wonder how the hell did primitive humans did away with Ra; there must be reason he never again attempted to connect to gate...