A new crack has been discovered in the Petermann Glacier in Northwest Greenland by Stef Lhermitte, an assistant professor at Delft University of Technology in the Netherlands. The crack was found by accident as Lhermitte was testing a methodology to detect melt using satellite images. The crack was determined to have appeared in July 2016 and had not been noticed by anyone else. Greenland is responsible for about one-third of the Earth's sea-level rise, so the potential breaking off of one of its largest glaciers is concerning.