Galaxies

The region of the universe photographed by the Hubble telescope is ridiculously small when compared to the entire night sky, and it covers a mere 1/30th the area of the full moon. The fact that at least 1500 galaxies could be photographically captured, in spite of the limited region depicted on the picture, was totally due to the immensity of the depths of space. Hence, further advanced galaxies are seen on the telescope's image "next" to much younger ones. In other words, the Hubble photograph is a selective snapshot across space and time that incorporates 342 individual photographs taken in the blue, infrared, red and ultraviolet range of wave lengths. Each photo of the identical region in the sky required an exposure of 15 to 40 minutes. Finally the many individual photos were assembled into a single one. This technique enables astronomers to guess the galaxies' age, distance, and components -- at least statistically. This bevy of material does not entirely explain every facet of the universe, however, and many questions remain unanswered. On this photographic montage appear galaxies with the spiral shape of our Milky Way; others resemble balls or eggs. Terrestrial astronomers are puzzled at this point about the origin of the elliptical, ballshaped galaxies, and hold heated and frank discussions about this subject. They ponder whether these galaxies are the product of a different type of collision with galaxies, or if they are collapsed gas masses from a very early period of the universe, which perhaps, may be a galactic archetype. These are but two of the countless questions astronomers are expected to resolve.[1]

Further Reading

References