Space crossword

3. A gigantic explosion in which a massive star collapses and throws it's outer layers into space.
4. A star that has collapsed under gravity to the point that the electrons and protons have smashed together to form neutrons.
7. The actual brightness of an object such as a star.
11. All of the frequencies or wavelengths of electromagnetic radiation.
12. Space and all the matter and energy in it.

1. Hertzsprung-Russell diagram a graph that shows the relationship a star's surface temperature and absolute magnitude.
2. The brightness of a star as seen from earth.
5. A large cloud of gas and dust in interstellar space; a region where stars are born.
6. A measure of how bright a star would be if it were seen form standard distance.
8. The distance that light travels in a year; about 9.46 trillions kilometers.
9. A small hot dim star that is the left over center of an old sun like star.
10. A collection of stars,dust,and gas bound together by gravity.