Started reading this book years ago, and never finished. Want to go back to it but cannot remember the title. The very beginning starts off with a conventional mission to Mars. Upon arrival of the astronauts a couple college kids open a worm hole to the ship and step through. Book than jumps forward to man having used this tech to colonize star systems. Later.on in book a star system far away is found to have a sphere completely encasing it, and a ship is built to travel to it l, basically skipping. That's most of what I can remember.