There is what seems to be, and there is what is. We look but we cannot see what is. We build instruments that do our looking and still these instruments cannot see everything. There is no limitless gaze. The horizon curves, the fog muffles, the lights and structures get fainter and fuzzier with distance. The redshift dims. Peeling back one layer leads only to another. This is the reality of the Universe in which we live. When we think we have it just right, we see an unimagined new rightness beneath.
David Block and Kenneth Freeman have been looking and measuring, classifying and pondering the Universe for a long time. We are fortunate they shared their story with us. This is a story about the avalanche of insight that follows the discovery of new techniques: of giant telescopes built by hand all around the globe and of the mysteries the builders solved and revealed through their drawings; of the photographic process and the replacement of vision by chemical images; of electronic antennae, cameras, telescopes, and satellites that are sensitive to radio, infrared, ultraviolet, x-ray, and gamma ray light. It is a story of the shrouds of the night that were slowly peeled back, of galaxies viewed both inside and out, like the x-ray fish in Collette Archer's painting below.
The Universe around us is rich with structure in both density and temperature. Some of this structure reveals itself by the light it radiates, the long or the short wavelengths depending on temperature and extinction, the bright or the dim light depending on distance, opacity, and power. Other structures emit no light at all, but show their presence only through gravity. Perhaps still others show their presence only through feeling. This is a very different Universe close to us than the Universe long ago and far away, which had much less structure, much more uniformity in temperature and density, and many fewer types of objects. It had no stars, no carbon or oxygen or other heavy nuclei, no galaxies An Epilogue
- just elementary particles and their mutual forces. How that Universe, now mapped and 401
measured with modern instruments, turned into the Universe around us, is a story being told by countless pixels of digital data, month-long simulations on the largest computers, and atom smashers that probe Big Bang energy densities. How that Universe sprung forth life that ponders and questions as we do is a story that still lies behind the thickest shroud.
Dr Bruce Elmegreen is a senior research scientist at the IBM TJ Watson Research Center in New York. He completed his doctorate at Princeton University; his supervisor was the late Lyman Spitzer Jr, one of the fathers of modern astrophysics after whom the Spitzer Space Telescope is named. Dr Elmegreen then spent three years as a Junior Fellow in the Society of Fellows at Harvard University and joined IBM in 1984, after holding a
faculty position at Columbia University. Dr Elmegreen was awarded the Dannie Heineman Prize in 2001 for theoretical studies of the interstellar medium, starbursts and the dynamics of spiral arms and bars in galaxies. A previous recipient of this prize was coauthor Kenneth Freeman. Dr Elmegreen has served on all three of the international Scientific Organizing Steering Committees for conferences on galaxy morphology and cosmic dust held on South African soil. Dr Elmegreen's winning design for a medal to commemorate the Transit of Venus in 2004 was struck in both gold and silver. A gold medal was awarded to Dr Elmegreen by the Governor of the Reserve Bank of South Africa, Tito Mboweni.
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