1. How do colors in a spectrum help us understand stars? Image from http://upload.wikimedia.org/wikipedia/commons/c/cd/Embryonic_Stars_in_the_Rosette_Nebul a.jpg Spectra and Stars (C) Copyright 2014 - all rights reserved www.cpalms.org

2. We can’t go to stars and planets to see what they are like. So we learn about them by studying the light that they emit or reflect. Deep space image from http://upload.wikimedia.org/wikipedia/commons/2/21/Hubble_Ultra_Deep_Field_NICMOS.jpg (C) Copyright 2014 - all rights reserved www.cpalms.org

3. Thinking about the spectra activity, what evidence do you have that we can learn something about stars from their light? 1. From Activity 1 about adding light……. 2. From Activity 2 about using c-spectra and colored. filters……. 3. From Activity 3 about light from a hot gas……… (C) Copyright 2014 - all rights reserved www.cpalms.org

4. NASA: Spectroscopy in Action PLAY VIDEO https://www.youtube.com/watch?v=oRm0z8ggJSk

5. Visible light ranges in wavelength from ~400 to ~700 nanometers. The color of light is the wavelength. Image from http://science.hq.nasa.gov/kids/imagers/ems/visible.html But visible light is only a small part of the electromagnetic spectrum. (C) Copyright 2014 - all rights reserved www.cpalms.org

6. Light is energy …….. energy travels in waves........ waves have properties! Waves only transfer energy without the physical movement of material from one location to another. Light travels through space at 300,000,000 m/s. One property of a wave is the wavelength – the distance between successive wave peaks. Electromagnetic waves are transverse waves. Image from http://upload.wikimedia.org/wikipedia/commons/5/5a/Crest_trough_wavelength_amplitude.png (C) Copyright 2014 - all rights reserved www.cpalms.org

7. Light travels as a wave in an infinite spectrum of electromagnetic radiation. (C) Copyright 2014 - all rights reserved www.cpalms.org Image from http://en.wikipedia.org/wiki/Microwave#mediaviewer/File:EM_spectrum.svghttp://en.wikipedia.org/wiki/Microwave#mediaviewer/File:EM_spectrum.svg The wavelength of an EM wave is inversely proportional to its frequency and also to it’s energy. The shorter the wavelength, the higher the frequency and the more energy the wave has. The range of all possible frequencies of electromagnetic radiation is called the electromagnetic spectrum.

8. Light is separated into its various wavelengths using a piece of glass called a prism. A rainbow is an example of continuous spectrum. Another Image that shows the experiment can be viewed at http://astronomy.nju.edu.cn/~lixd/GA/AT4/AT404/HTML/AT40401.htm (C) Copyright 2014 - all rights reserved www.cpalms.org CONTINUOUS SPECTRUM Image from http://commons.wikimedia.org/wiki/File:Spectral_lines_continous.png

9. Occur when the light coming from a gas is passed through the surfaces of a prism or c-spectra. Depending on whether or not the gas cloud is in front of a blackbody object, the spectrum will either be an emission line spectrum or an absorption line spectrum. Another Image that shows the experiment can be viewed at Image from http://astronomy.nju.edu.cn/~lixd/GA/AT4/AT404/HTML/AT40401.htm (C) Copyright 2014 - all rights reserved www.cpalms.org EMISSION & ABSORPTION SPECTRUM Image from http://commons.wikimedia.org/wiki/File:Visible_spectrum_of_hydrogen.j pg http://commons.wikimedia.org/wiki/File:Visible_spectrum_of_hydrogen.j pg

10. Different Types of Spectra Each element has different emission lines which show the same colors that are missing in the absorption line. (C) Copyright 2014 - all rights reserved www.cpalms.org Another Image that shows a comparison can be viewed at http://www.extremetech.com/extreme/167878-every-color-of-the-suns-rainbow-why-are- there-so-many-missing Image from http://commons.wikimedia.org/wiki/File:Visible_spectrum_of_hydrogen.jpg and Image from http://commons.wikimedia.org/wiki/File:Spectral_lines_continous.pnghttp://commons.wikimedia.org/wiki/File:Visible_spectrum_of_hydrogen.jpg

11. Each atom of a given element is unique and has unique properties, including what kind of color is emitted when it’s heated. (C) Copyright 2014 - all rights reserved www.cpalms.org Images from http://commons.wikimedia.org/wiki/File:Periodic_table_large.png

12. Hydrogen What is the difference between Emission and Absorption Spectra? The emission lines emit the color / wavelength. Absorption lines absorb the same color / wavelength. (C) Copyright 2014 - all rights reserved www.cpalms.org Emission Spectrum Absorption Spectrum Image from http://commons.wikimedia.org/wiki/File:Visible_spectrum_of_hydrogen.jpg

13. (C) Copyright 2014 - all rights reserved www.cpalms.org http://science.hq.nasa.gov/kids/imagers/ems/visi ble.html Identifying Absorption Lines of a Star (C) Copyright 2014 - all rights reserved www.cpalms.org Image from http://upload.wikimedia.org/wikipedia/commons/d/d7/Cumulative-absorption- spectrum-hubble-telescope.jpg

14. Black lines are caused by gases on, or above, the Sun’s surface that absorb some of the emitted light. The Mystery???? Some lines are not identified. Are they produced by elements that don’t exist on Earth? (C) Copyright 2014 - all rights reserved www.cpalms.org Image from http://www.extremetech.com/extreme/167878-every-color-of-the-suns-rainbow-why-are-there-so-many-missing Sun’s Absorption Spectrum

15. Ultraviolet (UV) light waves are invisible to the human eye. If we change the detector, we can ‘see’ these shorter wavelengths. (C) Copyright 2014 - all rights reserved www.cpalms.org Image from http://missionscience.nasa.gov/ems/10_ultravioletwaves.html Ultraviolet Image of the Sun

16. X-ray detectors are used by scientists to see and record the energy within the corona. Data was collected by x-ray detectors on satellites in orbit around the Earth by the Japan's Hinode spacecraft. (C) Copyright 2014 - all rights reserved www.cpalms.org Image from http://missionscience.nasa.gov/images/ems/emsXRays_mainContent_xray- sun.png X-ray Image of the Sun

17. Used to study the light from planetary images and satellite imagery. First telescope - Galileo in 1609. The eye detects visible light only. Radio telescopes - detects the very longest wavelength of light. Space Telescopes - detects different wavelengths, like X-ray, ultraviolet and infrared. Space Telescopes - operate in space to avoid the obscuring effects of our atmosphere. Chandra X-ray Observatory Spitzer Infrared Observatory Hubble Space Telescope - Optical (C) Copyright 2014 - all rights reserved www.cpalms.org Different Types of Telescopes and Detectors Images from http://www.nasa.gov/mission_pages/