Across
- 3. The average length of a star's main sequence stage in billions of years
- 5. A unit of number used to measure the extreme ages and temperatures of stars
- 6. The longest and most stable adult stage of a star's life cycle
- 11. The estimated temperature in millions of degrees needed to fuse heavier elements
- 12. A star that swells up and turns red as its core runs out of hydrogen
- 15. The process inside a star's core that smashes atoms together to release energy
- 16. An enormous star that expands and cools after using up its main hydrogen fuel
- 18. A gigantic, powerful explosion caused by a dying massive star
- 19. Stars that burn through fuel very quickly and end in giant explosions
Down
- 1. An object with gravity so strong that not even light can escape it
- 2. The super-dense remains of a massive star created after a supernova
- 4. A glowing shell of gas blown off by a dying medium-sized star
- 6. The amount of matter in a star, which controls how long it lives and how it dies
- 7. The hot, dense core left behind after a medium star dies
- 8. A measure of how bright a star looks from Earth
- 9. A early "baby" star made of contracting gas and dust before fusion begins
- 10. A huge cloud of dust and gas in space where new stars are born
- 13. The metal element created at the core of a massive star right before it explodes
- 14. A cooled-down white dwarf that no longer shines or gives off light
- 17. Newly formed stars that have recently started shining on the main sequence