Astronaut Scott Kelly was on NASA's International Space Staion, when he was amazed about was he saw. Monday afternoon, while floating somewhere over Russia, Kelly tweeted a picture of a breathtaking red aurora borealis, exclaiming, "I've never seen this before- red #aurora. Spectacular!"
The Aurora Borealis, or the Northern Lights, occurs around the north magnetic pole (at the south magnetic pole it's called an aurora australis) when highly charged electrons from solar winds interact with elements in the earth's atmosphere, such as oxygen and nitrogen. The color of the aurora depends on which atom is struck, and the altitude of the meeting. The most common color, yellow-green, typically comes from a reaction with oxygen at altitudes around 60 miles above the earth.
Red auroras are more rare and are produced by high-altitude oxygen, at heights of up to 200 miles. When this photo was taken, ISS was hovering about 251 miles above the ground.
An aurora is a natural light display in the sky (from the Latin word aurora, "sunrise" or the Roman Goddess of dawn) predominantly seen in the high latitude (Arctic, Antarctic) regions. Aurorae are caused by cosmic rays, solar winds, and magnetospheric plasma interacting with the upper atmosphere (thermosphere/exosphere). Their charged particles, mainly electrons and protons, enter the atmosphere from above causing ionization and excitation of atmospheric constituents, and consequent light emissions. Incident protons can also produce emissions as hydrogen atoms after gaining an electron from the atmosphere.
Most auroras occur in a band known as the auroral zone, which is typically 3° to 6° wide in latitude and between 10° and 20° from the geomagnetic poles at all local times (or longtitudes), most clearly seen at night against a dark sky. A region that currently displays an aurora is called the auroral oval, a band displaced towards the nightside of the Earth. Day-to-day positions of the auroral ovals are posted on the internet.
