NASA Earth on Instagram: "Arctic sea ice this year tied for the 10th lowest on record, @nasa and @nsidcnews report. Sea ice—or frozen seawater—forms and melts directly in the ocean and is different from icebergs or glaciers, which come from land-based ice. Every year around September, Arctic sea ice reaches its minimum extent. This year, sea ice reached its yearly minimum extent of 1.78 million square miles on Sept. 10, tying with 2008 as the 10th-lowest on record. #earth #NASA #ice #seaice #sci