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Ch. 27 Sec. 1

Ch. 27 Sec. 1. Tools of Astronomy. Radiation emitted or reflected by distant objects allows scientists to study the universe. Review Vocabulary. refraction: occurs when a light ray changes direction as it passes from one material into another. I. Radiation. Electromagnetic radiation

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Ch. 27 Sec. 1

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  1. Ch. 27 Sec. 1 Tools of Astronomy

  2. Radiation emitted or reflected by distant objects allows scientists to study the universe. Review Vocabulary refraction: occurs when a light ray changes direction as it passes from one material into another

  3. I. Radiation • Electromagnetic radiation • 1. Electric & Magnetic disturbances • 2. Travel as waves through space • 3. Electromagnetic Spectrum – includes visible light, infrared and ultraviolet radiation, radio waves, microwaves, X rays, and gamma rays.

  4. B. Wavelength and frequency • Wavelength - the distance between corresponding points on adjacent waves • Frequency - the number of waves or oscillations that pass a given point per second • a. Red light = 4.3 x 1014 Hz • b. Violet light = 7.5 x 1014 Hz

  5. Frequency is related to wavelength by the mathematical relationship c = λf, where c is the speed of light (3.0 × 108 m/s), λ is the wavelength, and f is the frequency.

  6. II. Telescopes • Collect electromagnetic radiation • 1. Focus image for recording • 2. Increase brightness (large aperture) • 3. Increases magnitude (size) • 4. Increases resolution (clearness)

  7. B. Imaging Devices Telescopes can also collect light over periods of minutes or hours. Other specialized equipment can be added to enhance images.

  8. C. Refracting telescopes Refracting telescopes use lenses to focus visible light.

  9. D. Reflecting telescopes Reflecting telescopes use mirrors to focus visible light. Can collect more light than reflecting telescopes

  10. E. Placement Away from city lights High elevations a. less atmosphere b. less pollution

  11. F. Non-optical Telescopes For all telescopes, the goal is to bring as much electromagnetic radiation as possible into focus. Infrared and ultraviolet radiation can be focused by mirrors in a way similar to that used for visible light.

  12. X rays cannot be focused by normal mirrors, and thus special designs must be used. Gamma rays cannot be focused, so telescopes designed to detect this type of radiation can determine only the direction from which the rays come.

  13. A radio telescope collects the longer wavelengths of radio waves with a large dish antenna and reflects them to a point above the dish. There, a receiver converts the radio waves into electric signals that can be stored in a computer for analysis.

  14. 2. Linked radio telescopes • Clearer image • More distant objects

  15. Electromagnetic Spectrum 1. Gamma rays 2. X-rays 3. Ultraviolet radiation 4. Visible light 5. Infrared radiation 6. Microwaves 7. Radio waves

  16. G. Interferometry 1. Images from several sources 2. Enhances detail

  17. III. Space-Based Astronomy A. Hubble Space Telescope (HST) • Launched 1990 • Orbits Earth every 97 minutes • Visible-light, infrared and ultraviolet imagery • James Webb Telescope (2014)

  18. B. Spacecraft • Robotic probes • a. Cassini (Saturn 2005) • b. Mars Reconnaissance Orbiter (2006) • c. New Horizons (going to Pluto : ETA July 2015)

  19. C. Human spaceflight The space shuttle provides an environment for scientists to study the effects of weightlessness on humans, plants, the growth of crystals, and other phenomena. Because shuttle missions last a maximum of just 17 days, long-term effects must be studied in space stations.

  20. C. Spinoff technology Many technologies that were originally developed for use in space programs are now used by people around the world. More than 1400 different NASA technologies, such as cordless tools, have been passed on to commercial industries for common use; these are called spinoffs.

  21. Personal Computers Colorization of black and white movies "Sound Guard" record cleaner Solar powered calculators Aluminized bags for snack food Weather satellites Halogen lights for cars Sports domes Microwave Ovens Pocket calculators Phone calls by satellite Laser guided missiles "Mylar" balloons "Blue Blocker" sunglasses

  22. Digital watches and thermometers"DirecTV", "Dish Network", etc "Kevlar" for bullet proof vests "Mini Mag" flashlights and fishing line Fiber optics for phone calls "Vortec" engines in GM cars "Ovation" guitars and helicopter blades Pacemaker batteries that last 20 years Compact Disks M R I medical scanners Electronic ignition in automobiles Laser scanners in stores "Bulb Miser" devices for long life light bulbs

  23. Weather Maps on television Juice boxes for "Hawaiian Punch", etc "The Patch" medical device Breathing systems for Mt. Everest climbers, "Flexon" eyeglasses and dental braces Cellular phones and beepers Cable Television, H B O, Showtime, etc Sunglasses that block 99% of U. V. light Pens that write upside down and under water Anti corrosive paint for bridges, boats, Scratch resistant coatings on sunglasses & the Statue of Liberty Football helmets for the NFL GPS Navigation Systems

  24. Radiation emitted or reflected by distant objects allows scientists to study the universe. • Telescopes collect and focus electromagnetic radiation emitted or reflected from distant objects. • Electromagnetic radiation is classified by wavelength and frequency.

  25. The two main types of optical telescopes are refractors and reflectors. • Space-based astronomy includes the study of orbiting telescopes, satellites, and probes. • Technology originally developed to explore space is now used by people on Earth.

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