Universe

3. is the hot, dense core of matter that remains from the collapse of a low-mass star
7. the actual brightness of a star
8. a small, incredibly dense ball of closely packed neutrons
9. a large collection of stars, gas, and dust that is held together by gravity
10. the region of the diagram where stars spend most of their lives
12. a gigantic explosion in which a high-mass star throws its outer layers into space
14. magnitude that is the measure of the brightness of a star whose distance is known from Earth
15. magnitude that is the measure of a star’s brightness as seen from Earth
17. a large cloud of gas and dust in space

1. a collection of large and small bodies that orbit our central star
2. an invisible object with gravity so great that nothing can escape it
4. when surface temperature of stars are plotted against their luminosity
5. the distance that light travels through space in one year
6. a large celestial body that is composed of gas and emits light
11. emit a beam of electromagnetic radiation that can be seen from Earth
13. is the word that scientists use to describe space and all of the energy and matter in it.
16. a spherical body of either rock or gas that orbits the sun