Astronauts witnessed a truly stunning natural phenomenon aboard the International Space Station Saturday and Sunday, one that few Earthlings get to appreciate up close. Luckily, they shared the experience with the rest of the planet via social media.NASA astronauts Scott Kelly and Kjell Lindgren and Japanese astronaut Kimiya Yui have been sharing amazing photos of red and green auroras flickering above Earth since Saturday. Kelly has diligently documented the lights on his Twitter feed.The incredible lights are likely the aftermath of a solar storm that made it to Earth on Aug. 12. Not only can the northern and southern lights be seen from the Earth, but astronauts get a unique view as they gaze down at the display.