Oil formed before that (from bacteria and plankton), but few … Evolutionary scientists say they have confirmed that 4.4 billion years is the age of the earth’s earliest rocks. Almost all the Earth’s known petroleum was formed less than 160 million years ago. Though there is some disagreement among biblical scholars about its exact age, the Earth is generally believed to be no more than a few thousand years old. In-Depth Article “Fossil Galaxy” Said to Show Conditions Soon After the Big Bang