Silhouette of a Solomon Island

Silhouette of a Solomon Island

Rennell Island is part of the Solomon Islands, a nation in the western Pacific Ocean located northeast of Australia and east of Papua New Guinea. Rennell, also known as Mu Nggava Island, lies 210 kilometers (130 miles) south of Guadalcanal—the nation’s main island.

This photograph, taken by an astronaut aboard the International Space Station, shows Rennell Island silhouetted against an ocean surface that is gleaming with sunglint. A line of small cumulus clouds casts shadows on the sea surface north of the island.

The lake at the east end of the island—also highlighted by sunglint—is Lake Te Nggano (also referred to as Tengano and Tegano). The lake is enclosed by a coral reef that rises above the sea surface and is densely forested, thus appearing as dark as the rest of the island. Te Nggano is the largest lake in the western Pacific Ocean.

Sunglint in images can reveal subtle features on the surface of water bodies (including the signature of internal waves). The brightest areas of sunglint in this image are along the east-facing coastlines. This is where comparatively smooth water surfaces reflected more sunlight back to the astronaut’s camera on the space station. On this day, the water was likely smooth in these areas because it was being sheltered from a west wind (indicated by faint wind streaks on the water surface). Films of oil have also been known to help smooth water surfaces and affect sunglint.

The eastern third of Rennell Island has been designated a World Heritage Site by UNESCO because of its many endemic species. Of the 50 bird species known on Rennell, 21 are endemic, and the island is also designated as an Important Bird Area (IBA). Crocker’s sea snake, now considered vulnerable, is a species that lives only in Lake Te Nggano. In 2013, the site was added to a list of World Heritage sites in danger due in part to the effects of logging in the area.

Astronaut photograph ISS068-E-39300 was acquired on January 8, 2023, with a Nikon D5 digital camera using a focal length of 380 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 68 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 Justin Wilkinson, Texas State University, JETS Contract at NASA-JSC, and Susan Runco (NASA retired).