Scientists are seen shoveling snow into the sack of the snowmelt. (Photo: Martin Leonhardt, Alfred-Wegener-Institut) At a Glance Researchers melted and strained a half-ton of frozen snow shipped from the South Pole.The same substance had already been found deep under the Pacific Ocean.The recent finding was in snow that's only about 20 years old. Some 20 years ago, researchers discovered ancient stardust buried deep in the floor of the Pacific Ocean. They deduced that the stardust – actually a substance...