The signal goes through the ionosphere to the satellite than to another satellite which has a link to the Earth. Starlink uses LEO, so there is 2400 km link(1200 km from/to the ground). 1 ms is time for the signal to travel for 300 km in a vacuum. So theoretically the lowest RTT could be about 8 ms. Right now RTT to my ISP is 2 ms.

I think your altitude figure is off by ~2x. "The satellites successfully reached their operational altitude of 340 miles (550 kilometers)" according to this: https://www.space.com/spacex-starlink-satellites.html

I found this https://www.reddit.com/r/Starlink/comments/i9w09n/list_of_co... It's pretty good for far remote regions like Alaska. Fibre channel will be much more costly with comparable RTT.

Neat, thanks!