I had to look long and hard for this.
Statement from Reki Kawahara (author of SAO) from his official twitter saying the stars and galaxy that Kirito saw is just the sky you see in open world games not actual stars and galaxies.
Link
Statement:
1.私たちがオープンワールドゲームで見る星空と基本的には同じものです。
2.具体的な距離はSAO26巻で明らかになるはずですが、地球と火星よりずっとずっとずっと近いです。
Translation:
1. It's basically
the same as the starry sky we see in open world games.
2.
The specific distance should be revealed in SAO Vol. 26, but
it is much closer than Earth and Mars.