Below are some of the most interesting and beautiful objects in the night sky, for you to explore with Navigate. Enjoy!
The Sloan Digital Sky Survey has taken images of more than 50 million galaxies,
from giant spirals to tiny smudges of light. Here are some of the most beautiful.
and a companion. Although the two galaxies appear to form a pair, they are
actually at much different distances. The smaller, fainter object is 7 times farther away.
, a spiral galaxy that we see nearly edge-on. The bright red star is in the
Milky Way, very, very close to us compared to the distant galaxy. The star makes a colorful
counterpart to the blue galaxy, although the two are unrelated.
, an elliptical galaxy with strange dust filaments. The dust
filaments may be the shredded remains of a small spiral galaxy that was
captured by the much larger elliptical.
, a distant spiral galaxy with unusually distorted spiral arms. Arms like
these normally arise from the gravitational effects of neighbor galaxies, but for
this object there is no obvious neighbor.
Clumps are loose collections of stars, gas, or galaxies held together by gravity.
Palomar 3 (also known as Sextans C) is a globular cluster, a collection of old stars orbiting the Milky Way.
, which is being torn apart by the Milky Way's gravity.
, an ultra-low surface brightness galaxy. Galaxies come in a
variety of sizes and luminosities; this galaxy is so faint that even the
SDSS's camera can barely see it.
, a nearby, blue, low surface brightness galaxy.
and its companion. These two galaxies are very young, full of young, blue hot stars.
A nearby group of galaxies centered on
. Galaxy groups typically have about 10-20 members.
VIII Zw 388
VIII Zw 388
, a picturesque group of galaxies, discovered and catalogued by famous astronomer Fritz Zwicky.
Moderately Red Shifted Galaxies
A cluster of
moderately far away. One of the major goals of the
SDSS is to learn how galaxies cluster, and to use the clustering to infer the
characteristics of the early universe.
Galaxies are found in clusters of hundreds or thousands, held together by their mutual gravity.
One of the SDSS's major goals is to understand how galaxies form clusters and larger structures,
up to the large-scale structure of the universe.
The ensemble of faint images is a superposition of
three clusters of galaxies
at different distances along the line of sight. The estimated redshifts of the clusters
are 0.38, 0.43, and 0.50. The different redshifts give rise to slightly different colors in the galaxies, with the most distant objects appearing to be the reddest.
, a well-known rich cluster, at a redshift of 0.0423, detected by the SDSS.
ZwCl 1710 (Abell 2255)
ZwCl 1710, also known as Abell 2255, a rich cluster, at a redshift 0.081, detected by the SDSS. This cluster was also detected in X-rays.
Sometimes, galaxies collide, or pass close enough to affect each other through the force of
gravity. Astronomers call these collisions and forces "interactions" of galaxies. Some
interactions seen by the SDSS are shown below.
, an interacting pair of galaxies. Note how the galaxies have distorted each other through their mutual gravity.
Another pair of violently interacting galaxies. The brighter object is called
NGC 428, a spectacularly blue
nearby spiral galaxy. The blue color indicates very active star formation in this galaxy.
UGC 10770, a young spiral galaxy,
undergoing a collision. This object is mentioned in many catalogs of interacting galaxies (ARP, etc).
NGC 7603 & PGC 07041
NGC 7603 and PGC 07041
NGC 7603 and PGC 07041, an interacting pair. Notice the "bridge" of stars and gas
between the two galaxies. The bigger object, NGC 7603, is a well-known Seyfert galaxy.
Seyfert galaxies have small, bright, active cores.
, a Seyfert galaxy with an active core. Notice the disturbed appearance of the
galaxy. This object may be the remnant of an old collision between two galaxies. As a
by-product of the collision, gas from one galaxy is being dumped onto a black hole at
the center of the other galaxy, giving rise to the active core.
The faint reddish object is a distant quasar
Quasars are the most luminous objects in the Universe. They consist of a giant
black hole in the center of a host galaxy. This object was the first to exceed
the magic distance threshold of z=5.0.