What is a star?
Stars are big balls of hot gas or plasma. They are formed when clouds of dust and gas in the universe collect in one area and are clumped together by gravity (a force which tries to pull two objects towards each other). The more gas and dust that gathers, the bigger the star becomes.
Not all the bright lights we see in the sky are stars. Some are satellites, some are aircraft and some are planets. Stars come in different colours depending on how hot they are. The coolest stars are red, then orange, then yellow. White stars are even hotter and blue stars are the hottest.
Constellations are groups of stars. Sometimes they look like animals and sometimes they look like people. Throughout history, people have told very fun and interesting stories about the different constellations.
Facts about stars
- The closest star to Earth is the Sun. It’s a yellow dwarf star.
- Some stars move in the sky but some are fixed like the North Star. This is why for centuries people have used the North Star to guide them.
- Most stars are between 1 and 10 billion years old.
- Most stars in the universe are red dwarfs, they are the smallest and most common. They are not as hot as other stars and do not explode.
- The smaller a star is the longer it lives. Big stars are very bright but they burn out faster.
