The presupposition of long ages is an icon and foundational to the evolutionary model. Nearly every textbook and media journal teaches that the earth is billions of years old.
Using radioactive dating, scientists have determined that the Earth is about 4.5 billion years old, ancient enough for all species to have been formed through evolution.
The earth is now regarded as between 4.5 and 4.6 billion years old.
The primary dating method scientists use for determining the age of the earth is radioisotope dating. Proponents of evolution publicize radioisotope dating as a reliable and consistent method for obtaining absolute ages of rocks and the age of the earth. This apparent consistency in textbooks and the media has convinced many Christians to accept an old earth (4.6 billion years old).