Exploding stars, also known as supernovae (10 letters), novae (5 letters) and novas (5 letters), are stellar explosions that occur when a star reaches the end of its life cycle. Supernovae are the most powerful type of explosion, releasing more energy than the sun will in its entire lifetime. Novae are less powerful explosions, while novas are even weaker. All three types of exploding stars can be seen in the night sky, and they are often used to measure distances in space.