1. Prologue Designer: Eric Kimsey The following powerpoint presentation was designed to fulfill the requirements of the TAPS program at Jefferson Labs in Newport News, VA summer 2006. This presentation was also designed to accompany and expound upon the topic of Light and the Electromagnetic Spectrum as required by the state of Virginia Physical Science SOL’s (PS.9c).

2. Spectroscopy A Tool of Astronomers

3. Definitions Spectroscopy- the study of the light from an object. Spectrometer- an instrument which spreads out light making a spectra. Spectra- range of electromagnetic energy separated by wavelength.

4. Astronomers use spectroscopy because it allows them to determine the makeup of stars… without having to be present to take samples.

5. Studying an objects spectra can tell scientists the composition of an object, its temperature, its density and its motion.

6. Two modern applications of spectroscopy in space…

7. Mars Exploration Mission The Mars Exploration Rovers were launched with the goal of searching for and analyzing rock and soils on Mars. They utilized several spectrometers to analyze samples. Mini-TES: miniature thermal emission spectrometer (examine rock, soil & atmosphere) MB: Mossbauer Spectrometer (examine mineralogy of rocks & soils) APXS: Alpha Particle X-ray Spectrometer (analyze elements in rocks & soils)

8. Cassini-Hyugen’s Mission Mission: to gather information on Titan (Saturn’s moon). VIMS: Visual and Infrared Mapping Spectrometer (gather data about surface, rings & atmosphere of Titan and Saturn). CIRS: Composite Infrared Spectrometer (searches for heat and by that gather information on the object’s composition.

9. 2 Basic Types of Spectra Continuous- energy of all wavelengths Discrete- energy at a particular wavelength –Emission or bright lines –Absorption or dark lines

10. Continuous Spectrum Also called thermal or blackbody spectra Spectra of stars, planets, moons Depends on temperature Ex: sunlight passing through a prism

11. Hotter objects Shift toward this end Cooler objects Shift toward this end Shorter wavelength Longer wavelength Continuous Spectrum continued

12. Discrete Spectrum Absorption Hot object Cool, thin gas Spectra Absorption spectrum Ex: stars, planets w/ atmospheres, & galaxies Each element has a unique signature of absorption lines. That pattern helps scientists identify the element(s).

13. Discreet spectrum- Emission Cold, empty space Spectra Emission spectrum Thin,hot gas Again, the pattern of the lines determines the identity of the element. Ex: comets, nebula & certain stars

14. Motion of Objects in Space Blue shift shows object is moving toward the observer. This shows the normal position or no motion. This shows a red shift meaning that the object is moving away from the observer. Compare the dark lines in the middle spectra to the dark lines in the other two spectra.

15. Spectroscopy Lab Determining the Spectra of Certain Elements

17. What type of spectra is shown here? Continuous Absorption Emission

18. What type of spectra is shown here? Continuous Absorption Emission

19. Why does this picture represent just the continuous spectrum of light?

20. Light is just one portion of the electromagnetic spectrum. Name 5 other parts of the EM spectrum.

21. Acknowledgements www.ipac.caltech.edu/Outreach/Edu/Spectra/spec.html www.astronomynotes.com/lights4.htm http://saturn.jpl.nasa.gov/spacecraft/instruments-cassini-cirs.cfm http://pmo-sun.uoregon.edu/~astrosites.html http://marsrovers.nasa.gov/overview

22. No way! Were you sleeping? Back to question #1

23. YES, we have a winner! To next question….

24. Pat yourself on the back! Next question

25. That is a definite NO! Back to 2 nd question