Permafrost polygons (IMAGE) University of Texas at Austin Caption An aerial image of ice wedge polygons next to Kaktovik Lagoon. The polygons are signs of ice in the frozen ground below, a solidified earth known as permafrost. Credit Nathan Sonderman Usage Restrictions Include photo credit 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.