• German scientists spotted the 2km (1.24mile) ring on a routine survey flight
  • The scar of broken ice was found in Antarctica's King Baudoin Ice Shelf
  • Scientists believe it was made by a 7-10 m wide meteorite that hit in 2004
  • Researchers in Antarctica at the time reported seeing dust left in the sky
  • They estimated it had exploded with the force of 12,000 tonnes of TNT
  • Infrasound stations also picked up the explosion and matched the location