The center of the local supergalaxy is either in or near the great Virgo cluster of galaxies located at a distance of 12 to 16 Mpc. Our position at the very edge of this supercluster is even more extreme than our somewhat out-riding position in the disk of our galaxy. Virtually all the matter concentrated in the supergalactic plane is to one side of our position and in the general direction of the zodiac signs Virgo and Libra.

A glance at the star maps (located elsewhere) will make the orientation of the supergalactic plane clear to the reader. The Supergalactic plane dominates the Autumn Equinox and the signs Virgo & Libra, just as the galactic plane dominates the solstice axis and the signs Sagittarius/Capricorn and Gemini/Cancer. It is of more than passing interest to notice that these two vast systems are at a right-angle (84°) to one another! and that the centers of the two systems (GC at 266°, SGC at 181° zodiac longitude) almost coincide with the zero points of Libra and Capricorn! A very meaningful analysis of the traditional Sun-Sign interpretation can be made with these facts alone. The midpoint between these two cosmic centers is at about the middle of Scorpio (Tropical).

Here are some facts concerning our Supergalaxy: It is a vast flattened supersystem or 'cloud of clusters' and the plane of maximum concentration defines the supergalactic equator. The overall diameter is about 40 megaparsecs and the thickness some10 megaparsecs and a volume of 16,000 Mpc (cubed) that contains about 10 (to the 15th) solar masses distributed among the tens of thousands of member galaxies.

A much larger cluster of galaxies is that in the direction of Coma Berenices. The Coma cluster (as it is called) is a dense knot of an elliptical shape about six times as distant as the Virgo cluster and containing perhaps 10 times as many galaxies! Some 3000 such very large clusters have been catalogued. Other supergalaxies have been discovered. The nearest other supergalaxy is the Southern Supergalaxy that can be seen almost edge-on extending through the constellations Cetus, Fornax, Eridanus and Horologium to Dorado. Its apparent nucleus is marked by a dense group of more than a dozen galaxies (NGC 1365, 1374, 1379, 1380, 1381, 1387, 1389, 1399, 1404, 1437 & 1427).

At a distance modulus of 27.0, it is only slightly farther away than the Virgo cluster and is of similar size,. Astronomers feel (at this time) that there is little likelihood that supergalaxies are themselves part of still larger structures. Recent research suggests that the tendency toward clustering falls off rapidly after a mass of supergalactic proportions is reached. A list of some of the major giant clusters and superclusters is given elsewhere. At this point, well over a million external galaxies have been counted by astronomers and such research is still at an early stage.

Click on the image to see a bigger view.

Distribution of nearby groups of galaxies over the celestial sphere in Supergalactic coordinates. Group of galaxies shown here are within 10 to 16 megaparsecs. Note marked concentration toward the Supergalactic plane (horizontal line).

Copyright (c) 1997-99 Michael Erlewine