Age of the earth only 8000 Years?

The Bible says no such thing! Certain fundamentalists have worked out figures like that by the scientific expedient of adding together the perceived ages of the Old Testament prophets! Not the most sensible way, I contend. It may help to look at the teachings today of the oldest and by far the largest Christian denomination, the Roman Catholic Church. It has no problem with the Big Bang, a 13.7 billion year Universe, or, indeed, evolution of life on Earth (or anywhere else, possibly) including the human race. In fact, one of the early proponents of the Big Bang theory was a Catholic priest!