Scientists are looking for the world's oldest ice in Antarctica

Scientists are working in Antarctica and believe that the continent holds the world's oldest ice. They believe ice on the continent is hundreds of thousands or even millions of years old. Exactly how old the ancient ice could be, scientists don't know. They aren't sure how long ice could survive.Princeton University geochemist John Higgins says that he might be surprised to find ice that's 5 million years old, but that's not unfathomable. Previously, a group of researchers discovered what they said was an eight million-year-old ice sample in a buried glacier. The age of this sample was established by carbon dating volcanic ash found on the ice.

However, that date is a subject of debate. Scientists are searching for ancient ice samples because inside those ice samples will be pockets of ancient air from when the ice was formed. Those ancient air bubbles found in the ice samples allow scientists to directly capture air from the distant past. Researchers say that it's sort of like having a time machine.

Higgins and colleagues on his team have obtained an ice sample from Antarctica in the Allan Hills region dated at 2.6 million years old. He says it's the oldest ice sample that they have high confidence in the age of and has air inside. The sample was dated by analyzing trace amounts of argon gas trapped inside the ice.

Another sample discovered was 2 million years old and was in good enough condition that the bubbles trapped inside were used to measure greenhouse gases like carbon dioxide and methane. The samples were quality enough to give a snapshot of what the atmosphere at the time looked like. Doctor Higgins recently tweeted a video showing ancient ice melting and the gases trapped inside bubbling up through the ancient water.