Center of the galaxy

April 9, 2003 on 11:42 pm | In Ad Rem | Comments Off

There are many places in the universe which create immense gravitational forces. Individual stars are surprisingly on the lower end if measuring scale. Black holes are inescapably strong, but at a distance their pull is no stronger than an equally massive star. Globular clusters are regions in which star growth is, or was at one time, exceedingly rapid. Hydrogen nebulas coalesce and form hundreds and thousands of hot, blue young stars. Most globular clusters observed now consist of older red dwarves. Gathered at the center of these clusters are often white dwarves, neutron stars, and conceivably a small black hole. The concentration of massive objects allows the cluster to bend the fabric of the universe far more than your average areas of the galaxy.

By far the largest purveyors of gravitational forces in the universe are galaxies themselves. These monsters of mass can be in many different shapes. You rarely find a spherical galaxy as large as a spiral or elliptical galaxy. Spiral appears to be the most common, and has massive gravitational arms revolving around the center. These arms are fascinating; they are not made up of simply a specific bunch of stars and nebula. The arms are gravitational waves which concentrate matter as they come, and then spread it back out as they go by. A single star will go in and out of these arms constantly in its life; it gets tremendously closer, and again tremendously far away from its neighboring stars each wave. This phenomenon isn’t yet completely understood.

The center of a galaxy is probably the most fascinating. It appears that most large galaxies have a super-massive black hole powering the surrounding revolutions. These black holes have been measured at being sometimes billions of times more massive than our sun. Some galaxies have been observed to have two super-massive black holes in their center! Sagittarius A, the black hole in the center of the Milky Way, is approximately 2 million times the mass of our sun. The event horizon on this black hole has a diameter twice that of our solar system. That is approximately 24,000,000,000 kilometers in diameter. That is a volume of 127,000,000,000,000,000,000,000,000,000,000 cubic kilometers (127 nonillion km3)! This is what makes the galaxy go-round. Also in the center are giant hydrogen clouds, enormous stars and things referred to as canes, threads, snakes, and arcs. This mass is enough to keep the inner galaxy revolving around it. The inner galaxy then adds its mass to keep the outer galaxy revolving.

Dark matter is likely one of the most abundant things to provide mass in the galaxy, but it is an unknown. My own hypothesis is it is simply hydrogen clouds not actively lit up by an active source of energy, so it does not emit any form of detectable energies itself. I will discuss many of the points in this article, of which I today just touched on, at another time.