Readers were curious about green icebergs, aliens and more

Your letters and comments on the March 30, 2019 issue of Science News

Going green

Researchers found iron oxides trapped in a sample of green Antarctic ice. The compounds may explain why typically blue-hued icebergs can sometimes appear green, Jeremy Rehm reported in “Tiny bits of iron may explain why some icebergs are green” (SN: 3/30/19, p.