A spectral line of hydrogen has an absorption laboratory...

A spectral line of hydrogen has an absorption laboratory wavelength of $122 \mathrm{nm}$. It is observed in the spectrum of a quasar at $130 \mathrm{nm}, 180 \mathrm{nm},$ and $330 \mathrm{nm} .$ What are the redshifts $(z)$ of these clouds? What would be their distances, assuming Hubble's law (and using $V=c \times z$ )?

Key Concepts

Doppler Effect

The Doppler effect refers to the change in frequency or wavelength of a wave as the source and the observer move relative to one another. In astronomy, it explains how the motion of celestial objects – typically their recessional or approach velocities – results in a shift of spectral lines, providing essential information about their kinematics.

Redshift

Redshift is the phenomenon where light or other electromagnetic radiation from an object is increased in wavelength, or shifted to the red end of the spectrum. This shift is quantified by the parameter z, defined as the fractional increase in wavelength from the laboratory (or rest) value to the observed value. It is a key observable in astrophysics for measuring the relative motion and velocity of distant objects.

Spectroscopy

Spectroscopy involves analyzing the electromagnetic spectrum of objects to identify characteristic lines corresponding to specific atomic transitions. By comparing the observed positions of absorption or emission lines with their known laboratory wavelengths, astronomers can deduce information about the physical conditions and motions of celestial objects.

Hubble's Law

Hubble's law is the empirical relation in cosmology that indicates the recessional velocity of a galaxy or other astronomical objects is proportional to its distance from the observer. By using the relation V = c × z in the linear approximation (where c is the speed of light and z is the redshift), astronomers can estimate distances to objects, contributing to our understanding of the expanding universe.

Transcript

Please give Ace some feedback