"Gravity" is the fourth book in the SODIUM series. As Earth scrambles to build its defenses a massive fleet approaches from Epsilon Eridani. We must fight and we must win to survive. The SODIUM series hits high gear as the massive battle for Earth gets underway. Do we have what it takes or will Man's short history come to an abrupt end? Find out as the thrilling SODIUM series continues!Also available from this author:"SODIUM:1 Harbinger" - a sci-fi action adventure of a first alien encounter in the 1950s"SODIUM:2 Apocalypse" - the aliens return in modern day and attack"SODIUM:3 Fusion" - the aliens return with an even larger force"SODIUM:4 Gravity" - a new world explored and the battle for Earth moves into high gear!"SODIUM:5 Assault" - it's time to take the fight to their world!"SODIUM:6 Defiance" - the final fight for Earth's survival. Winner rules the galaxy!