1. Electromagnetic energy has properties of both _____________________ and __________________________. 2. The ___________________________ of a wave is the distance from one wave crest to the next,

1. Electromagnetic energy has properties of both _____________________ and __________________________. 

2. The ___________________________ of a wave is the distance from one wave crest to the next, while its __________________________ is the number of waves that passes a point in one second.

 3. The longer the wavelength of an electromagnetic wave, the more __________ that it contains. 

4. The speed of all electromagnetic waves in space is ____________________ kilometers per second. 

5. The seven different parts of the electromagnetic spectrum, stated from the shortest wavelength to the longest, are (1) ___________________________ ______________; (2) __________________; (3) _______________________ ______________; (4) ___________________ __________________; (5) __________________ __________________; (6) ___________________; and (7) _____________ ___________________.

 6. Scientists use ________________________________ to measure the color of light. 

7. The _____________________________ of the surface of a star can be determined from a star’s color. 

8. Bands of light in a star’s spectrum allow scientists to determine what _____________________ are in the star. 

9. The brightness of a star as seen from Earth is its ________________________ __________________________. The actual brightness of a star, calculated by knowing its distance from Earth and apparent brightness, is its _____________________ ____________________ or ___________________. 

10. The distance to stars that are close to Earth can be measured by ___________________. 

11. The _____________________ ___________________ allows scientists to determine whether a star is moving towards or away from Earth. If the light from the star is _____________-shifted, it is moving away from Earth. If the light is __________________-shifted, it is moving towards Earth. 

12. One of the main pieces of evidence supporting the Big Bang Theory is the fact that all distant galaxies are __________________-shifted, meaning that they are moving __________________ from Earth. 

13. Another piece of evidence supporting the Big Bang Theory is the ___________________________ background of space, which was measured with radio telescopes.