The term 'FIREBALL IN THE SKY' can be solved by the crossword clue 'SUN' with a 3 letter answer. This phrase is often used to describe a meteor, which is a small piece of rock or dust that enters Earth's atmosphere and burns up due to friction. Fireballs are usually brighter than the planet Venus and can be seen in the night sky. They are often associated with shooting stars, which are streaks of light that appear in the sky when a meteoroid enters the atmosphere.