The Doppler Shift of Galaxies Lab

Name: __________________________________________ Date: _____________ Block: ______ THE DOPPLER SHIFT OF GALAXIES LAB VIOLET RED Standard Hydrogen Spectrum VIOLET RED Virgo A VIOLET RED M65 Spiral Galaxy in Leo VIOLET RED The Coma Pinwheel Galaxy VIOLET RED Cetus A VIOLET RED M58 Spiral Galaxy in Virgo VIOLET RED M109 Spiral Galaxy in Ursa Major VIOLET RED Andromeda The Doppler shift allows us to study the light emitted by an object to determine whether that object is sitting still ( stationary ), coming towards us ( approaching ) or moving away from us ( receding ). When the visible spectra of an object’s light is shifted towards the red end of the visible spectrum, we know that object is moving away from us. Conversely, when the spectra is shifted towards the blue end of the visible spectrum, we know that object is moving towards us. If the spectrum is the same as the standard spectrum, the object is not moving. Stationary Moving away from observer Moving towards observer On the right, you will find the standard spectrum for the element Hydrogen, which is the material that makes up the vast majority of galaxies in the Universe. Below that, you will find the spectra from a variety of galaxies. Use these diagrams to fill out the table on the next page. When you are down with the table, answer all questions in complete sentences.

GALAXY NAME SPECTRUM IS _____-SHIFTED (circle one) THIS GALAXY IS... (circle one) Virgo A RED or BLUE RECEDING or APPROACHING M65 Spiral Galaxy in Leo RED or BLUE RECEDING or APPROACHING The Coma Pinwheel Galaxy RED or BLUE RECEDING or APPROACHING Cetus A RED or BLUE RECEDING or APPROACHING M58 Spiral Galaxy in Virgo RED or BLUE RECEDING or APPROACHING M109 Spiral Galaxy in Ursa Major RED or BLUE RECEDING or APPROACHING Andromeda RED or BLUE RECEDING or APPROACHING 1. Describe the motion of the majority of these galaxies. Are most receding or approaching? _____________________________________________________________________________________ _____________________________________________________________________________________ 2. If this is the same motion of virtually all galaxies in the Universe, what can you say about the general movement and size of the Universe? _____________________________________________________________________________________ _____________________________________________________________________________________ 3. Assuming your answer from question two is correct, what can you say about the size of the Universe as you go further and further back into the past? _____________________________________________________________________________________ _____________________________________________________________________________________ 4. How is the movement of the Andromeda galaxy different from the movement of the other galaxies? _____________________________________________________________________________________ _____________________________________________________________________________________ 5. What problem may this pose for our galaxy in the future? _____________________________________________________________________________________ _____________________________________________________________________________________

A) red end of the spectrum, indicating the star's movement toward Earth B) red end of the spectrum, indicating the star's movement away from Earth C) blue end of the spectrum, indicating the star's movement toward Earth D) blue end of the spectrum, indicating the star's movement away from Earth 1. The diagrams below represent spectral lines of hydrogen gas observed in a laboratory and the spectral lines of hydrogen gas observed in the light from a distant star. Compared to the spectral lines observed in the laboratory, the spectral lines observed in the light from the distant star have shifted toward the A) red shift, which indicates that the star is moving away from Earth B) red shift, which indicates that the star is moving toward Earth C) blue shift, which indicates that the star is moving away from Earth D) blue shift, which indicates that the star is moving toward Earth 2. The diagram below represents the light spectra given off by the same element as observed under two different conditions. Spectrum A was observed when that element was heated in a laboratory. Spectrum B shows the same element as seen in the light from a distant star. The light spectrum observed from this distant star shows a

A) decreasing in size B) increasing in size C) decreasing in distance from Earth D) increasing in distance from Earth 3. The red shift of light from distant galaxies provides evidence that these galaxies A) toward Earth B) away from Earth C) in an elliptical orbit around the Sun D) in a circular orbit around the Sun 4. The diagram below represents the bright-line spectrum for an element. The spectrum of the same element observed in the light from a distant star is shown below. The shift in the spectral lines indicates that the star is moving A) contracting B) expanding C) staying the same size D) expanding and contracting regularly 5. Most astronomers agree that at the present time universe is A) observations of supernova explosions. B) the discovery of black holes. C) observations that the Doppler red shift becomes greater as we look at more distant galaxies. D) observations that most galaxies are rotating 6. The major evidence supporting the "Big Bang" theory is A) The star's spectral lines have shifted toward the ultraviolet end of the spectrum and the star is moving toward Earth. B) The star's spectral lines have shifted toward the ultraviolet end of the spectrum and the star is moving away from Earth. C) The star's spectral lines have shifted toward the infrared end of the spectrum and the star is moving toward Earth. D) The star's spectral lines have shifted toward the infrared end of the spectrum and the star is moving away from Earth. 7. The diagram below shows a standard spectrum compared to a spectrum produced from a distant star. Which conclusion can be made by comparing the standard spectrum to the spectrum produced from this distant star? A) revolving around the Sun B) revolving around the Milky Way C) moving away from Earth D) moving toward Earth 8. When viewed from Earth, the light from very distant galaxies shows a red shift. This is evidence that these distant galaxies are