Galaxy Clusters

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Galaxy Clusters Our Local Group
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Merging Galaxies
Polar Ring Galaxy NGC 4650
Antennae Galaxy NGC 4038
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The Latest HST Image
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Advanced Camera for Surveys in detail
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NGC 3079 A Starburst Galaxy
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Hubble's Law And the Expanding Universe
As well as classifying galaxies into different
types, Edwin Hubble observed the spectral lines
of many different galaxies. He discovered that
almost every galaxy is moving away from us!
What's more there is a relationship between the
recessional speed (or redshift) of a galaxy and
distance it lies away from us! Galaxies that
are further away are moving more quickly! So a
galaxy with a large redshift is not only moving
away from us very quickly but is in fact a very
long way away from us!
redshift (z) v / c (l l0)/l
V H0 D
H0 Hubble's Constant gives the age of the
universe! It is believed to be 71 km/s/Mpc
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Quasars
/Quasi-stellar radio sources
The most distant objects in the known
universe have extremely redshifted spectral lines
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Active Galactic Nuclei
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