NASAさんのインスタグラム写真 - (NASAInstagram)「We first saw Earth in far ultraviolet light in 1972, in a photo taken by Apollo 16 astronauts. Today, the GOLD mission has a constant view of Earth in this kind of light. 👉 Swipe to compare! These images highlight Earth’s ionosphere, a region of the upper atmosphere that is mostly invisible to our eyes — aside from aurora or airglow, if you’re in the right place at the right time. Named for the electrically charged ions that move about freely in this region, the ionosphere absorbs UV light from the Sun and re-emits it to space, making it shine in these wavelengths. In 1972, Apollo 16 astronauts John Young and Charles Duke photographed Earth in far ultraviolet light from the lunar surface. This was the first photo of our planet in far ultraviolet. Today, from its vantage point in geostationary orbit, the GOLD mission tracks changes in the ionosphere’s ever-changing temperature, density and composition by measuring far UV light. This lets scientists piece together the forces that shape conditions in this part of the atmosphere, which is critical to many Earth-orbiting satellites and everyday technology, including successful transmission of radio signals and GPS. Read more: https://go.nasa.gov/2JO1rOO #nasa #space #science #moon #apollo #apollo50th」7月19日 0時57分