1. Unit 7 Vocabulary

2. Universe
Space and everything that exists within it including all matter and energy

3. Galaxy
A collection of stars, gas, dust and other objects bound together by gravity

4. Star
A large body of gas which is held together by gravity and emits light and energy through nuclear fusion

5. Nebulae
clouds of dust and gas; site of star formation; remains of dead or dying stars

6. Main Sequence Star
A stable star which is actively fusing hydrogen and is shown in a diagonal pattern within a H-R diagram

7. Absolute Magnitude
a measure of how bright a star really is, if all stars were the same distance from Earth

8. Apparent Magnitude
a measure of how bright a star appears as seen from Earth

9. Hertzsprung-Russell Diagram
a graph that shows the relationship between the brightness, surface temperature, and color of stars

10. Luminosity
total amount of light (energy) emitted by a star or other celestial body

11. Spectroscope
A tool for analyzing light; used to determine the elements present in the light source

12. Spectra
different colors of light emitted based on the chemical composition of the light source

13. Electromagnetic Spectrum
a classification of all forms of radiation by wavelength and frequency; used to study components of the universe

14. Electromagnetic Wave
A wave of electricity and magnetism that travels at the speed of light

15. Wavelength
The distance between any point on a wave to the same point on the next cycle of the wave

16. Frequency
the number of times a wave passes a certain point in a given amount of time

17. Big Bang Theory
a current scientific theory concerning the early development of the universe from a dense state
which began
and is still
expanding