Science, Science & Marxism

Ian Murray seamus2001 at attbi.com
Thu Jan 10 13:10:39 PST 2002


----- Original Message ----- From: "Justin Schwartz" <jkschw at hotmail.com>

The sociological account _doesn't_ explain why science works. It isn't supposed to. It's supposed to tell us, to the extent anything can, what science _is_. The reason these practices work, what explains why science is successful, is the fact that in them we have stumbled on the techniques that allow us to find out the way world is. That's not a fact internal to the practices. This is of fcoyrse the realsit answer. I will let the constructivists offer their own answers.

jks

==============

Well one thing the constructivists and realists can agree on is that the color of the universe is *ugly* and needs to be changed. :-)

< http://www.newscientist.com/news/news.jsp?id=ns99991775 >

The Universe is turquoise, say astronomers

14:43 10 January 02 Eugenie Samuel, Washington DC

Astronomers have revealed the true colour of the Universe - it is somewhere between "pale turquoise and medium aquamarine".

The discovery may appear to be as useless as the "answer" to life, the Universe and everything given in the Hitchhikers Guide to the Galaxy - 42 - but the colour is helping the astronomers trace the history of star formation.

Ivan Baldry and Karl Glazebrook at John Hopkins University in Baltimore, Maryland, found the cosmic colour by combining light from over 200,000 galaxies within two billion light years of Earth. They worked with data from the Australian 2dF Galaxy Redshift Survey at the Anglo-Australian Observatory in New South Wales, Australia.

Combining the light gave a spectrum with a peak in the blue part of the optical spectrum - due to the large number of young stars burning hydrogen - and another in the red part of the spectrum -due to the glow of older red giants burning heavier elements.

Researchers can analyse such spectrums like fossils, to reveal the history of star formation in a given galaxy. But this is the first time anyone has calculated a spectrum for enough galaxies to be representative of the whole Universe.

"Not my favourite colour"

When Baldry and Glazebrook worked out how their spectrum would appear to the human eye, which is not equally sensitive to all wavelengths of light, they came up with a pale green.

"It's not my favourite colour," says Glazebrook. "It's on the greenish side of white, a subtle colour." For any computer buffs wishing to put the colour on their desktops, the red-green-blue values you will need are 0.269, 0.388 and 0.342.

Glazebrook and Baldry have already used their result to rule out some models of star formation. In 1994, astronomers working with images of the early Universe from the Hubble Space Telescope claimed that star formation in the Universe was slow to start with, peaked around six billion years ago, and has tailed off towards the present day.

But Glazebrook says such a scenario would produce a redder colour than is seen, because more old red stars from the early Universe would still be around. "We take account of star death in our model as well," he says.

Instead Glazebrook believes star formation peaked one to two million years after the Big Bang. This is consistent with results announced by NASA on Tuesday. At that time, the Universe was mainly blue, due to the large number of young stars, but it's now greening out and will turn red as stars age over the next five billion years.



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