An astronaut onboard the International Space Station (ISS) took this photograph of sunglint, which is characterized by specular or mirror-like reflections of the Sun on relatively smooth water surfaces as observed by an astronaut or satellite. This photo features sunglint on the Aegean Sea around the Greek volcanic islands of Milos and Antimilos, about 150 kilometers (100 miles) south of Athens.
Within an area of sunglint, the brightest silver patches are sunlight reflected directly back to the camera, while less bright areas represent some diffusion of the sunlight in other directions. These patterns can be generated by surfactant oils—either human-made or natural—floating on the water surface; wind and water currents; or both acting together. These factors influence the surface roughness of the water and the degree of light reflectance. Sunglint highlights other surface and sub-surface features that are not typically visible, such as internal waves and the swirls of gyres. It can also accentuate ship wakes.
At approximately 150 square kilometers (60 square miles), Milos is the largest island of the South Aegean Volcanic Arc. Islands in this archipelago are known for their rich deposits of sulfur, bentonite, quartz, and other volcanic minerals, which are mined and exported for their commercial and industrial applications. The Aggeria bentonite mine is visible on the northern part of the island.
Astronaut photograph ISS067-E-153817 was acquired on June 25, 2022, with a Nikon D5 digital camera using a focal length of 400 millimeters. It is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by a member of the Expedition 67 crew. The image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by Amber Turner, Jacobs, JETS Contract at NASA-JSC, Justin Wilkinson, Texas State University, (JETS Contract), and Susan Runco, NASA-JSC (retired).