This is Urania. Despite her young looks and small body, she is already 25 years old.
Because of her appearance, a lot of ponies see her as a child and usually treat her that way, which is one of the few things that can make her angry.
Urania has an asymmetric cutie-mark. On the right side of her flank is the Lyra constellation which contains the star Vega, while the left side has the constellation of Aquila with the star Altair.
She got her cutie-mark at quite a young age after discover