The Southern Pinwheel (M83)
Type: Barred Spiral Galaxy
There are many beautiful galaxies in the Universe, but this one, also known as M83, is among the most beautiful, even if beauty is only in the eye of the beholder. However, what makes this galaxy peculiar is the large number of supernova explosions that took place in it. Currently, there are eight active supernovas under observation, but the remains of hundreds more have been noted. The reasons for the large number of supernovas remain unexplained, but what is explainable is the huge number of active star forming regions, which are shown in pink. The pink color is the result of the enormous amount of UV light generated by millions of young, new stars that acts on surrounding clouds of dust and gas.
Sombrero Galaxy (M104)
Type: Unbarred Spiral Galaxy
It is fair to say that the central bulge, or nucleus, of a galaxy consists of one, homogeneous collection of stars. However, in the case of the Sombrero Galaxy, the nucleus is composed of several, clearly separate clusters of stars, although this is not readily apparent in optical light. Astronomers are also at a loss to explain the presence of the dust lane that encircles the core, but what is more puzzling is the intricate detail in the dust lane. Investigations into the origin and nature of the dust lane are ongoing, but a clear answer seems to be a long way off.