Universe

3. A small, extremely dense remnant of a star with such high gravity that not even light can escape its pull
5. the hot, condensed object at the center of a nebula that will become a new star when fusion reactions begin
9. A star that has burned through all the hydrogen in its core, causing it to expand and cool down
10. a massive explosion that occurs when the outer layers of a dying star rebound off its inner core

1. The process of small atoms combining to form larger atoms
2. A change in the wavelength of sound or light waves caused by the source of the waves moving toward or away from the observer
4. a system of millions or billions of stars, together with gas and dust, held together by gravity
6. The diagonal stripe of stars though the middle of an H-R diagram that contains 90% of all stars. Hot, bright stars are on the top left, while cool and dim stars are on the bottom right.
7. A unit for measuring distance, equal to the distance a beam of light travels in one year
8. A large cloud of gas and dust that collapses in on itself from its own gravity, creating heat and forming a star