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918. Problem 56.25 (RHK) We have to find the observed wavelength of the
656.3-nm
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line
of hydrogen emitted by a galaxy at a distance of
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Solution: Click For PDF Version We assume that the Hubble’s law is applicable in calculating the receding
speed of the galaxy, which is at a distance of
Hubble’s law is
Therefore, the recessional speed of the galaxy at a distance of
For relativistic speeds the Doppler shift can be obtained from the formula
The wavelength of the
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,
emitted by a galaxy at a distance of
