The Spectrum of a Galaxy Is Observed to Have a Hydrogen

question 27

Essay

The spectrum of a galaxy is observed to have a hydrogen emission line,normally found at 656.3 nm,with a measured wavelength of 856.3 nm.What is its distance if the Hubble constant is 72 km/s/Mpc?

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Definitions:

Adenine

One of the four nucleobase molecules used in forming nucleotides of the nucleic acids DNA and RNA; it pairs with thymine in DNA and with uracil in RNA.

Thymine

A nitrogenous base found in DNA, paired with adenine, and is one of the four nucleotide bases in DNA.

Nucleosomes

Fundamental subunits of chromatin, composed of a segment of DNA wound around a core of histone proteins, facilitating DNA packing in the cell nucleus.

Histones

Proteins that package and order DNA into structural units called nucleosomes, playing key roles in gene regulation.