Narrator: This is Science Today. Researchers at the University of California, Berkeley have proved a thirty year old way test to date geological times is very reliable. Geologist Paul Renne says the argon-argon dating method was used to date the eruption of Mt. Vesuvius which destroyed the ancient Roman cities of Pompeii and Herculeaneum over one thousand years ago. Renne says history books have recorded this event right down to the hour.
Renne: It occurred between 12 and one o'clock in the afternoon of August 24th 79 A.D.
Narrator: With this knowledge, Renne decided to test the argon-argon technique's accuracy. That test was off by just seven years. Renne says he hopes this kind of validation, will quiet down skeptics who don't believe the Earth is very old.
Renne: That really, I think, should enhance people's appreciation of the fact that we can date human evolution going back 5 million years. The validity of the basic principles is just not open to question.
Narrator: Renne's next step is to use the technique to accurately date events which have no recorded timeline. For Science Today, I'm Larissa Branin.