Petty Officer 2nd Class John Thompson, a boatswain's mate aboard the Coast Guard Cutter Sequoia, and Dr. Joe Haxel, a research assistant with the National Oceanic and Atmospheric Administration, prepare special floats used to deploy a hydrophone in Challenger Deep near the Federated States of Micronesia, Jan. 11, 2015. The crew of the Sequoia and NOAA scientists deployed the hydrophone in an attempt to listen to ambient sound in the deepest part of the Challenger Deep. (U.S. Coast Guard photo by Petty Officer 2nd Class Tara Molle)