Death Star
The Death Star is a type of fictional mobile space station and galactic superweapon featured in the "Star Wars" space opera franchise. The first Death Star is stated to be more than 100 km to 160 km in diameter, depending on source. It is crewed by an estimated 1.7 million military personnel and 400,000 droids. The second Death Star is significantly larger, between 160 km to 900 km in diameter depending on source, and technologically more powerful than its predecessor. Both versions of these moon-sized fortresses are designed for massive power-projection capabilities, capable of destroying multiple naval fleets or entire planets with one blast from their superlasers.
1972 Great Daylight Fireball
Analysis of its appearance and trajectory showed the object was about 3–14 m (10–45 ft) in diameter, depending on whether it was a comet made of ices, or a stony and therefore denser asteroid. Other sources identified it as an Apollo asteroid in an Earth-crossing orbit that would make a subsequent close approach to Earth in August 1997. In 1994, Czech astronomer Zdeněk Ceplecha reanalysed the data and suggested the passage would have reduced the asteroid's mass to about a third or half of its original mass (reducing its diameter to .)