The Life of Stars

4. the element which constitutes mostly on the outer parts of the star
5. estimated number of stars in the universe
7. type and _____ influenced how each star is formed
10. occurs in the center of the cloud and begins to glow brightly once temperature reaches 15,000,000°C
12. a huge explosion which contains tremendous amount of energy and can have a temperature up to 1,000,000°C
14. as stars glow during nuclear fusion, hydrogen changes to ____
15. when such star collapse, planetary nebula is created and can be used as building material for planets in developing solar systems
17. it drags the gas in nebula together
19. the color which glow when stars' outer parts expand and cool
20. elements oxygen, nitrogen, and _____ are formed in massive stars when carbon atoms get pulled due to temperature increase
21. coined the word 'black hole'
23. it is where a star is born
24. black holes were known before ad ______
25. it is formed when helium fuse upon reaching 200,000°C
26. this make a nebula have a stronger gravitational pull

1. the result when star more massive than the sun remains massive after supernova and has no nuclear fusion supporting the core and collapse by its own gravity
2. the first black hole discovered
3. the kind of star produced from dead medium-sized stars wherein gravitational pull leads to the loss of the star's matter collapsing inwards and compacting to become extremely dense
6. it is what becomes when massive star's core, which is 1.5 to 4 times massive as the sun, remains after becoming a supernova
8. a cold, dark star produced when white dwarf has been exhausted after it will no longer emit light
9. a ring around the core of the star formed from the remains of exploded hydrogen
11. what is called when neutron star starts to spin often emits radio waver and occur in pulses
13. the kind of star which dies once final helium atoms fused into carbon atoms
16. a kind of star which rises from nuclear fusion once it stabilizes at 15,000,000°C and contracts slightly
18. throughout this phase, hydrogen in outer parts carries on burning and center gets hotter and hotter
22. how a star will react in the red giant phases should depend on ____