Slices through the 3-dimensional map of the distribution
of galaxies from the Sloan Digital Sky Survey (SDSS).
The earth is at the center, and each point represents
a galaxy, typically containing about 100 billion stars.
Galaxies are colored according to the ages of their stars,
with the redder, more strongly clustered points showing
galaxies that are made of older stars. The outer circle
is at a distance of two billion light years. The region
between the wedges was not mapped by the SDSS because dust in
our own Galaxy obscures the view of the distant universe in these
directions. The lower slice is thinner than the upper slice,
so it contains fewer galaxies.
Credit: M. Blanton and the SDSS.
(Click above image for .jpg format or here for .tiff.)
A map of stars in the outer regions of the Milky Way Galaxy,
derived from the SDSS images of the northern sky, shown in a
Mercator-like projection. The color indicates the distance of the stars,
while the intensity indicates the density of stars on the sky.
Structures visible in this map include streams of stars
torn from the Sagittarius dwarf galaxy, a smaller 'orphan' stream
crossing the Sagittarius streams, the 'Monoceros Ring' that encircles
the Milky Way disk, trails of stars being stripped from the
globular cluster Palomar 5, and excesses of stars found towards
the constellations Virgo and Hercules. Circles enclose
new Milky Way companions discovered by the SDSS; two of these
are faint globular star clusters, while the others are faint
dwarf galaxies.
Credit: V. Belokurov and the SDSS.
A mosaic showing 36 of the the 500+
Type Ia supernovae discovered by the SDSS-II Supernova Survey.
Each image is centered on the supernova, which usually stands out
as a bright point near or within the galaxy that hosts it.
The light of the supernova, powered by the thermonuclear explosion
of a single white dwarf star, can outshine that of the tens
of billions of stars in its host galaxy. A mosaic of 484 SDSS-II
supernovae can be found
here.
Credit: B. Dilday and the SDSS.
