Drill Site (IMAGE) Princeton University Caption Princeton University-led researchers have extracted 2 million-year-old ice cores from Antarctica -- the oldest yet recovered -- that provide the first direct observations of prehistoric atmospheric conditions and temperatures. They used data from the ice cores to answer long-held questions about how our current colder, longer glacial cycle emerged. Credit (Photos by Sean Mackay, Boston University) Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.