Spectroscopy
description
Transcript of Spectroscopy
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).
SpectroscopyA Tool of Astronomers
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.
Astronomers use spectroscopy because it allows them to determine the makeup of stars… without having to be present to take samples.
Studying an objects spectra can tell scientists the composition of an object, its temperature, its density and its motion.
Two modern applications of spectroscopy in space…
Mars Exploration MissionThe 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)
Cassini-Hyugen’s MissionMission: 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.
2 Basic Types of Spectra• Continuous- energy of all
wavelengths• Discrete- energy at a particular
wavelength– Emission or bright lines– Absorption or dark lines
Continuous Spectrum• Also called thermal
or blackbody spectra
• Spectra of stars, planets, moons
• Depends on temperature
Ex: sunlight passing through a prism
Hotter objectsShift toward this end
Cooler objectsShift toward this end
Shorter wavelength
Longer wavelength
Continuous Spectrum continued
Discrete Spectrum Absorption
Hot object
Cool, thin gas
SpectraAbsorptionspectrum
Ex: stars, planets w/ atmospheres, & galaxies
Each element has a unique signature of absorption lines. That pattern helps scientists identify the element(s).
Discreet spectrum-
Emission
Cold, empty space
Spectra
Emissionspectrum
Thin,hotgas
Again, the pattern of the lines determines the identity of the element.
Ex: comets, nebula & certain stars
Motion of Objects in SpaceBlue shift shows object ismoving 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.
Spectroscopy Lab
Determining the Spectraof Certain Elements
What type of spectrais shown here?
•Continuous•Absorption•Emission
What type of spectrais shown here?
•Continuous•Absorption•Emission
Why does this picture represent just the continuous spectrum of light?
Light is just one portion of the electromagnetic spectrum.
Name 5 other parts of the EM spectrum.
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
No way! Were you sleeping?
Back to question #1
YES, we have a winner!
To next question….
Pat yourself on the back!
Next question
That is a definite NO!
Back to 2nd question