Aurelion Sol is massive but not as massive as you think.
Many people seem to think he is galaxy sized, but he isn't. If you want a sense of scale, watch his teaser again. You get to see his star whiz past a spear. A targonian spear, which Pantheon wields. Pantheon's own spear is roughly 1.5 times his own height.
And the baby star is roughly double that.
When it reaches Asol's hand it is roughly one third it's size, something his ingame models support.
His hands are, by his model, 1/10 as long as his body from belly to head top when he floats showing his chest.
This means that Asol when sitting idle, is roughly 90 times(thats 1.5 for the spear, times 2 for the star, times 3 for the hand, times 10 for the body) Pantheon's own height. Let's say Pantheon is roughly... six feet. That put's Aurelion Sol at about 540 feet tall in am idle position.
EDIT sorry thanks to HTC VIVE i realized i missed that it expands at the end. It increases in diameter by about about 9-11 times.
So he's actually like 5400 Feet from lower belly to tip of head. Over a full mile.
Is that massive? Fuck yeah. Is it as big as people seem to think? Fuck no.
And if you want his full length, from the same point he folds in half his tail adds like .3-.4 so like 2.4 times that.
12960 feet or 2.45 miles.