Science Vocabulary

1. the repetitive variation, typically in time, of some measure about a central value
3. an apparatus for producing and recording spectra for examination
4. the total amount of energy emitted per unit of time by a star, galaxy, or other astronomical object
9. the magnitude of a celestial object as it is actually measured from the earth
13. a type of galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless image
16. how cold or hot something is
17. the galaxy we are living in right now
18. a fixed luminous point in the night sky that is a large, remote incandescent body like the sun
19. The theory of the explosion that started the expansion of the universe
20. a group of huge single stars, star systems, etc. held together by gravity

2. A galaxy that does not have a regular shape
5. the distance between the two corresponding parts of a wave
6. A galaxy with a bulge in the middle and arms that spiral outward in a pinwheel shape
7. a change in the identity or characteristics of an atomic nucleus that results when it is bombarded with an energetic particle, as in fission, fusion, or radioactive decay.
8. the SI base unit of thermodynamic temperature, equal in magnitude to the degree Celsius.
10. the magnitude of a celestial object as it would be seen at a standard distance of 10 parsecs
11. diagram A graph relating the surface temperatures and absolute brightness
12. A large cloud of gas and dust in space
14. all of space and everything in it
15. An astronomical object or celestial object is a naturally occurring physical entity, association, or structure that exists in the observable universe