Ice cores give us an extremely useful timeline of the earth. Scientists drill down through a thick layer of ice and pull up a column that may contain plants, animals, pollen, ash, and other markers that tell us about the earth thousands or even millions of years ago. Air bubbles in their ancient pristine state can be studied, and chemicals like carbon dioxide reveal the earth's conditions from their time.
A 31-foot ice core was retrieved from the ice covering Antarctica's Ong Valley in 2017 and '18. Scientists have determined that the ice core is made up of two glaciation events (because glaciers drift), one from three million years ago, and the one underneath is between 4.3 and 5.1 million years! The oldest ice core dated before that was a mere 2.7 million years old. There will be years of analysis of this ancient ice that will tell us more than we ever knew about what happened on earth five million years ago. Read more about this record-breaking ice core at New Atlas. -via Damn Interesting
(Image credit: Jaakko Putkonen)