Out of the Darkness
The week's news reminds us that the universe can be both violent and mysterious. Chandra X-ray Observatory images of 3C321 show that it is composed of two galaxies orbiting one together, with one galaxy firing on the other. Every galaxy yet observed contains at its centre a massive Black Hole. In this image, X-ray data from Chandra is violet, optical data from Hubble is orange, and radio data is blue. The Black Hole at one galaxy's core is obscured by dust, giving it an hourglass shape. One of the twin jets blasts out the upper right into the neighbour galaxy. Chandra Press Release.
One reason people cling to belief in "dark energy" is that 2/3 of the Universe's mass seems to be missing. The GM=tc^3 Theory predicts, and WMAP confirms that average density is a "critical" value $\Omega$ = 1. The visible galaxies, and even the dark mass surrounding them, only account for about 1/3 of this total. This has created a void in which theorists can insert fantasies of repulsive energy.
Large scale maps like the Sloan Digital Sky Survey show that galaxies are arranged in sheets with enormous voids between them. A fish in the Barrier Reef knows to avoid dark holes, because something hiding in those holes could eat her! We can only hope that scientists are more intelligent than fish. Since the "voids" contain most of the Universe's volume, they could contain many massive unseen objects.
Gamma Ray Bursts are some of the most powerful explosions in the Universe. Earlier this year GRB 070125 suddenly flared where no object had appeared before. The location in the constellation Gemini is more than 88,000 light years from any known galaxy. Searches by the Palomar Observatory and telescopes atop Mauna Kea showed no signs of surrounding dust. Something, possibly a giant Black Hole, caused the GRB. There could be many more similiar objects in the voids between galaxies. NASA press release
The jet attack of 3C321 shows us how violent the Universe can be. About 2/3 of the Universe is hidden from our eyes. This dark Universe could contain massive Big Gulp Black Holes or other exotic objects. Sometimes this dark Universe erupts into visiblity like GRB 070125. There is far more out there than meets the eye.
More about 3C321 and the anniversary of Australia's first satellite at Carnival of Space!