1. Tools of Astronomy

3. Study of Light Newton (1666): studied light traveling through a prism & saw a spectrum of colors: ROYGBIV Huygens (1670s): determined light travels in waves; shorter wavelengths are refracted (bent) more than longer wavelengths – Led to the creation of spectroscopy—the science of the properties of light

4. Sun’s Light Spectroscopes  break Sun’s light into the various colors, each with its own wavelength ROYGBIV=visible spectrum Visible spectrum is only a small part of the entire spectrum of electromagnetic radiation given off by stars/galaxies

5. EM radiation Electromagnetic waves --> range of electric and magnetic waves that travel through space – transfer energy – travel through space – travel at the speed of light—300,000 km/s Include: – UV light=sunburns – Infrared=heat – X-rays, microwaves, gamma rays (CT scans)

6. Electromagnetic Spectrum: the continuum of radiation released by star --classified by wavelength (red longer, blue shorter) --wavelength=distance between the peaks on a wave --frequency=the # of waves that pass a point per second As wavelength decreases, freq. increases  they are inversely proportional

7. How is this info. used by astronomers? Visible light= temp of stars spectrums of common elements in stars Radio telescopes=pick up radio emissions to create images of the object Refracting tele: lenses bring light into focus Reflecting tele: mirrors bring light into focus Interferometry: combines several telescope images to make a very detailed image X-ray telescopes=picks up energy (radiation) from supernova explosions, galaxies & black holes Hubble telescope=infrared instruments pick up nebulas & cool stars

9. Gamma rays viewed when observing the moon X rays shot at a heavy metal (beneath the hand) that can be processed to show density Hubble-low Earth orbit; 1990 (in)- 2013/2021(out); 347 mi above Earth (reflecting telescope) – Why send a telescope into outerspace? 1) The earth's atmosphere distorts and blurs images, so the Hubble produces images much clearer than those that can be produced on earth (although there have also been improvements in technology for earth-based telescopes). 2) Some frequencies are absorbed by the atmosphere, and can only be observed from space. This is why we have launched telescopes to view the universe in a variety of frequencies (gamma ray, X-ray, infrared, etc.)

10. Sun (l) and Galaxy collisions (r) X-ray telescope images

11. Early Space Missions (t) Rockets- engines that have everything they need for the burning of fuel (doesn’t even require oxygen [air]) – Use both liquid and solid fuels Satellite- object that revolves around another object orbit=curved path followed by a satellite as it revolves around an object

12. Space shuttles transport astronauts, satellites, and other materials to and from space. – Space shuttles are reusable which is less expensive and less wasteful – International Space Station= laboratory in space for long term research Completed in 2010 (page 645) (t)