Undoubtedly, the crew aboard the International Space Station (ISS) has spectacular views. The ISS and its Cupola observatory module is an awesome vantage for viewing cities at night and even witnessing potentially tragic natural events such as major storms.
The crew also gets to see some of nature's most beautiful displays, auroras.
The International Space Station has an official Twitter account which is a great follow, and the account posted some photos of a recent aurora display. At the time, the ISS's orbit was as high as 51. 6° above the equator. The team also added the new images to ist ever-growing Flickr album of auroras.
'The International Space Station was orbiting 264 miles above the North Atlantic when this photograph was taken of an aurora streaming above the Earth's horizon. The Earth's airglow, an optical phenomenon caused by cosmic rays striking the upper atmosphere, blankets the horizon. Credit: Roscosmos'
You don't need to be in outer space to view beautiful aurora displays. Auror, often referred to as 'northern lights' in the northern hemisphere where they are famously observed in the northern reaches of North America and Europe, results from electrons from space interacting with oxygen and nitrogen gases in Earth's atmosphere. The electrons transfer energy to molecules in the atmosphere, exciting the molecules. When molecules return to their respective normal states, light energy (photons) is released. If this event occurs in great enough frequency and intensity, you can see the light energy from Earth's surface with the naked eye. This can occur at any time, but the energy is low enough that it is only visible in a dark sky.
Image credit: NASA
What produces these electrons? Magnetic storms on the sun. The sun has a natural cycle during which its magnetic field completely changes and the sun's north and south poles flip. This occurs every 11 years or so and is called the solar cycle. The solar cycle impacts more than the magnetic poles of the sun. It also affects activity on the surface of the sun. As the magnetic field changes, more sunspots occur on the sun's surface.
Auroras can appear as different colors, depending upon which gas electrons are interacting with and at what intensity. Excited oxygen is responsible for the familiar yellow-green aurora display, although it can also produce a red light. Nitrogen gives bluer light. Ultraviolet light is also emitted, which requires special cameras to detect.
During this aurora display, as seen in Maine, United States, I saw green, pink, purple and blue auroras. This means that the electrons were exciting both oxygen and nitrogen particles in the atmosphere. You don't need to live incredibly far north (or south) if the geomagnetic activity is strong enough.
There are also different shapes to aurora displays. You can see auroras that look like moving curtains in the sky, but they can also appear as arcs and spirals. Even in a single night, the shape of the display can change dramatically. Scientists believe this is due to where the electrons enter the magnetosphere and what caused them initially.
'The International Space Station was orbiting 263 miles above Romania when this photograph was taken of the city lights of Sweden and Finland with an aurora above the Earth's horizon. The dark area in between the two Scandinavian nations is the Baltic Sea. Credit: Roscosmos'
Back to viewing auroras from space, in its coverage, Digital Trends highlighted a cool NASA documentary from earlier this month. You can check out 'Down to Earth: The Astronaut's Perspective' below. It features incredible footage from the ISS and numerous interviews with astronauts, asking them about their experiences. You can see auroras from space about halfway into the video.
If you'd like to capture photos of the auroras for yourself, there are tons of great resources available. As an aurora hunter myself, spaceweather. com is my go-to website to keep tracking of current solar wind conditions, sunspots and to read about the odds of viewing auroras. There's luck involved, but the first step is having a good source of information. For photography tips, Dave Morrow has written an excellent guide. His guide contains everything you need to know.
(Via Digital Trends)
. dpreview.com2021-1-28 01:00