2 Fast-Moving Fireball
On October 13, 1990, two astronomical stations detected the passage of an Earth-grazer meteor over Czechoslovakia and Poland. Three other independent observers in Czechoslovakia and a fourth person in Denmark also confirmed the sighting. The fireball was caused by a 44-kilogram (97 lb) meteoroid, which descended into the Earth’s atmosphere to a minimum height of 98 kilometers (61 mi). It was moving at a speed of around 42 kilometers per second (26 miles per second), about 20 times faster than the fastest manned aircraft in the world.
For the nearly ten seconds it was visible in the night sky, the Earth-grazer traveled a distance of 409 kilometers (254 mi). After that, the meteor left the atmosphere and returned to space, now with a reduced speed. Its mass was also reduced; after burning a little in the atmosphere, it lost 350 grams (0.77 lb) of material. To verify the object’s trajectory, NASA ran computer simulations, whose results were similar to direct observations and confirmed that the meteor left the Earth. A Czech camera station that is part of the “European Fireball Network” program photographed the Earth-grazer in mid-flight. The image shows the bright object moving across the visible sky near its highest point.