Death Wave

"In Ben Bova's previous novel New Earth, Jordan Kell led the first human mission beyond the solar system. They discovered the ruins of an ancient alien civilization. But one alien AI survived, and it revealed to Jordan Kell that an explosion in the black hole at the heart of the Milky Way galaxy has created a wave of deadly radiation, expanding out from the core toward Earth. Unless the human race acts to save itself, all life on Earth will be wiped out. When Kell and his team return to Earth, many years after their departure, they find that their world has changed almost beyond recognition.…