Universe

2. an invisible object with gravity so great that nothing can escape it
4. the distance that light travels through space in one year
5. a large cloud of gas and dust in space
7. a large celestial body that is composed of gas and emits light
8. the region of the diagram where stars spend most of their lives
10. is the hot, dense core of matter that remains from the collapse of a low-mass star
14. a gigantic explosion in which a high-mass star throws its outer layers into space
16. a large collection of stars, gas, and dust that is held together by gravity
17. magnitude that is the measure of the brightness of a star whose distance is known from Earth

1. a collection of large and small bodies that orbit our central star
3. is the word that scientists use to describe space and all of the energy and matter in it.
6. the actual brightness of a star
9. a small, incredibly dense ball of closely packed neutrons
11. when surface temperature of stars are plotted against their luminosity
12. magnitude that is the measure of a star’s brightness as seen from Earth
13. a spherical body of either rock or gas that orbits the sun
15. emit a beam of electromagnetic radiation that can be seen from Earth