1. THE SUN-EARTH-MOON SYSTEM Chapter 28

2. The best tool to study the universe is the light emitted from it – Radiation We study Electromagnetic Radiation Electric and magnetic disturbances traveling through space as waves We can only see the visible light part of the spectrum

3. Electromagnetic Spectrum Arranged according to wavelength and frequency Type of radiation is classified by its wavelength

4. Wavelength & Frequency Wavelength – the distance from one wave to another Frequency – the number of waves that pass a given point in a certain amount of time

5. c = λ f c = speed of light (3 x 10 8 m/s or 300,000,000 m/s) λ = wavelength f = frequency *Remember ALL electromagnetic waves travel at the speed of light With this equation, if you know one, you can find easily find the other.

6. Telescopes GOAL : To bring as much radiation as possible to a focus Benefits 1. Modify them to observe all wavelengths 2. Collects from distant objects and focuses it to a point where it can be studied 3. Allows use of other special equipment 4. Used to make time exposures the human eye may miss

7. Visual Telescopes Visual telescopes are used to focus visible light (also work for infrared and UV) Refracting Reflecting

8. Refracting Telescopes 1 st used, made around 1600 Uses Lenses Objective Lens – Largest Eye Piece Lens Second When light passes through objective lens, it focuses the light away from the lens. The larger the objective, the more light it can collect

9. Refracting Telescope

10. Reflecting telescopes Uses mirrors The larger the mirror, the more light collected A flat mirror reflects the light to the eyepiece lens Most telescopes used today

11. Reflecting Telescopes

12. X-Ray Telescopes Can’t be focused by normal mirrors because x-rays aren’t easily reflected Arrangement of cylindrical mirrors allows x-rays to be guided to a precise focus to form an image

13. Radio Telescopes Large dish that reflects the waves to focus above the dish