Trail from Ship Exhaust Leaves 'A' in the Sky

You may not have seen it, but in July there was a large "A" written in the sky over the ocean near the Kamchatka Peninsula, in far-eastern Russia. The image of the A, published on Sunday (Dec. 27) on NASA's Earth Observatory website, shows how ocean-going ships produce a stream of exhaust gases that leaves tracks across the sky behind them, called ship tracks. A camera aboard NASA's Aqua satellite took the image on July 27.