In the real world, the Tunguska Event, or Tunguska explosion, was a powerful explosion that occurred near the Podkamennaya (Lower Stony) Tunguska River in what is now Krasnoyarsk Krai of Russia, at around 7:14 a.m. (0:14 UT, 7:02 a.m. local solar time) on June 30, 1908 (June 17 in the Julian calendar, in use locally at the time). Although the cause is the subject of some debate, the explosion was most likely to have been caused by the air burst of a large meteoroid or comet fragment at an altitude of 5–10 km above Earth's surface.