An astronaut aboard the International Space Station photographed a sunset that looks like a vast sheet of flame. With Earth’s surface already in darkness, the setting sun, the cloud masses, and the sideways viewing angle make a powerful image of the kind that astronauts use to commemorate their flights.
Thin layers of lighter and darker blues reveal the many layers of the atmosphere. The lowest layer—the orange-brown line with clouds and dust and smoke—is known to scientists as the troposphere, the layer of weather as we experience it. Astronauts see the atmosphere like this roughly every 90 minutes, as they view sixteen sunrises and sixteen sunsets every day. Astronauts often comment on how thin and fragile Earth’s atmosphere seems.
It is the smoke and particles of dust in the atmosphere that give the strong red color to sunsets. In fact, the astronaut was looking directly toward one of the dustiest parts of the southern hemisphere, where consistently strong winds blow dust from the arid Patagonian deserts of South America out into the ocean. From their altitude of 400 kilometers (250 miles), astronauts can see more than 2000 kilometers to the horizon, taking this view most of the way to the dust source even though they were half way between South America and South Africa.
Astronaut photograph ISS049-E-49442 was acquired on October 27, 2016, with a Nikon D4 digital camera using a 240 millimeter lens, and 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 49 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 M. Justin Wilkinson, Texas State University, Jacobs Contract at NASA-JSC.