One of the primary evidences used to justify the belief in a five-billion-year-old earth is the fact that long-age radioactive isotopes have decayed into daughter elements which we find today within the crystals of rocks (like granite). During the decay of many radioactive isotopes, helium nuclei are given off (which almost instantaneously change to extremely stable helium atoms). At current decay rates, this process should have taken billions of years to reach the current level. This dating technique is presented as the premier proof that the earth is biliions of years old. What follows is the rest of the story.
As radioactive elements decay, helium atoms are deposited into rock crystals. Helium atoms are so small that they easily leak through the rock structure and escape into the atmosphere. The rate at which helium leaks out of the rocks has recently been measured, and all of the helium produced by radioactive decay should have left the rocks if these formations were millions of years old. Yet the rock still contains much of the helium produced by this decay process. This helium is still locked into the rocks because there hasn't been enough time for it to escape from the rocks. This means that the radioactive decay could not have happened billions of year ago. Apparently there was a burst of radioactive decay within the last 10,000 years, possibly corresponding to when the earth was created, during the worldwide flood, or both. These are the types of scientific observations which make creation science so exciting.
From A Closer Look at the Evidence by Kleiss, April 3.
