Doppler shift question (galaxy movement)

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SUMMARY

The discussion centers on calculating the velocity of a distant galaxy based on the Doppler shift of an emission line of hydrogen. The rest wavelength of hydrogen is 656 nm, while the observed wavelength is 662.6 nm. Using the formula for velocity, the calculated speed of the galaxy is 3018 km/sec, indicating that the galaxy is moving away from Earth. The answer has been confirmed as correct by participants in the forum.

PREREQUISITES
  • Understanding of the Doppler effect in astronomy
  • Familiarity with the concept of wavelength and its measurement
  • Knowledge of basic physics equations related to velocity
  • Ability to perform calculations involving scientific notation
NEXT STEPS
  • Study the principles of the Doppler effect in light and sound
  • Learn about redshift and blueshift in astronomical observations
  • Explore the implications of galaxy movement on cosmology
  • Investigate the use of spectroscopy in measuring celestial velocities
USEFUL FOR

Astronomy students, astrophysics enthusiasts, educators preparing quiz materials, and anyone interested in understanding galaxy movement and the Doppler effect.

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Homework Statement



In a distant galaxy, an emission line of hydrogen that has a rest wavelength of 656 nm has an observed wavelength of 662.6 nm. Is the galaxy moving away from us or toward us? How fast is it moving in (km/sec)?


Homework Equations



velocity = ((shifted wavelength - rest wavelength)(c)) / rest wavelength

The Attempt at a Solution



velocity = ((6.626 x 10^-10 km - 6.56 x 10^-10 km)(3 x 10^5 km)) / 6.56 x 10^-10 km = 3018 km/sec

My answer is: the galaxy is moving away from us at 3018 km/sec. I'm hoping someone can tell me if this answer is correct. My instructor assigned this as a homework question and will be using it as a quiz question as well, so it's a double whammy if I don't have the right answer.
 
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