Astronauts living and working aboard the International Space Station have been posting some dazzling images of our planet's auroral displays. Auroras typically appear as ribbons of green and red light in the sky, and are caused by energetic particles from the sun interacting with atoms in the Earth's atmosphere. European Space Station astronaut Thomas Pesquet has posted several stunning shots to social media. Check them out. "These last few days have been auroraspectacular!," Pesquet tweeted this week.