From: Michele Wiegand (michele@ulster.net)
Date: Fri Jan 11 2002 - 13:47:20 MST
On 11 Jan 2002, at 8:19, Kalkor wrote:
<snip>
Life is probably about as common in the universe as interstellar dust
clouds... some emit beautiful light, some reflect beautiful light, some just
get in our way of seeing other things. The cosmos is indifferent to it and
I'm sure high energy radiation blasts interstellar dust clouds AND life to
smithereens on a regular basis.
--- There's an article in the NY Times today: Scientists Paint Universe as a Vast Sea of Green By JOHN NOBLE WILFORD WASHINGTON, Jan. 10 — The universe, by definition, holds everything imaginable and then some. It has stars and planets and moons, life here and possibly there, red giants and white dwarfs and — the ogres to top all ogres — big, bad black holes. It even has color, astronomers have concluded. If it were possible to see the universe as a whole, from afar, it would appear pale green, between aquamarine and turquoise. That is the conclusion of two astronomers from Johns Hopkins University, who mixed the varied hues in visible light of 200,000 galaxies on their palettes and saw green. They announced the results here today at a meeting of the American Astronomical Society. "From one perspective, it's surprising that it turns out green, because there are no greenish stars," said Dr. Karl Glazebrook of Johns Hopkins. "But it's the large numbers of old red stars and young blue stars in the universe that gives us the green." Although it takes a mixture of blue and yellow to make green in pigments, light sources combine in a different way. A blend of blue and red produces what Dr. Glazebrook described as "the standard shade of pale turquoise, but a few percent greener." Dr. Glazebrook and his colleague, Dr. Ivan Baldry at Johns Hopkins, conceded that they were having "a bit of fun." But they had a serious purpose, as well. They said the research could help assess theories of star formation and evolution. For their research, the astronomers used data from galaxies at a distance of two billion to three billion light-years from Earth. The survey was conducted by the Anglo-Australian Observatory in Australia. The astronomers first combined the data into a spectrum chart. The wavelengths of visible light plotted on the chart showed the intensity, or total amount of emitted light, of the galaxies in the survey. They then transformed the chart into a rainbow of colors, replacing each wavelength with the color the human eye sees at that wavelength. An analysis of this rainbow of component colors yields information on the prevalence of various chemical elements in the universe, which provides clues to the lives and deaths of stars. To determine the overall color of the universe, the astronomers used methods established by ophthalmologists to calculate the human eye's response to particular wavelengths of color. Then all the colors were, in effect, blended. As Dr. Glazebrook explained in an interview: "If you put all 200,000 galaxies in a box, the average color would be green. And if you had a huge eyeball and could observe the whole universe at once, you would see the color green." But at different times, far in the past or into the future, the cosmos would project different colors. The astronomers said the early universe probably started with a blue period, when young, hot blue stars predominated. As new star formation has declined and the population of aging, cooler red stars is proportionally much larger, the universe has moved into a middle green period. Billions of years from now, when nearly all surviving stars turn red with age, Dr. Glazebrook said, the universe is expected to enter its final red period. But for now, if there are little green men out there somewhere, they must feel proud to be the color of their universe.
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