Archives for the 'cosmology' Category
Cosmic Background Radiation Anisotropy
Published on 4 Oct 2006 at 3:37 pm.
2 Comments.
Filed under cosmology.
The winners of the 2006 Nobel Prize in physics have been announced. They are John C. Mather (NASA Goddard Space Flight Center) and George F. Smoot (Lawrence Berkeley National Laboratory). The award was “for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiaton.”
Rather than discussing the people themselves, I thought […]
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The sort-of emptiness of space
Published on 6 Jul 2006 at 4:31 pm.
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Filed under Uncategorized, cosmology, physics.
Space is empty. There is nothing in a vacuum. In space, no one can hear you scream (because there is nothing to transmit sound). Well, sort of. As it often turns out, what we are told is often a simplification of reality. As it turns out, space isn’t really empty. It is full of things. […]
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The Malmquist Bias
Published on 22 May 2006 at 6:29 pm.
1 Comment.
Filed under astronomy, cosmology.
What is the Malmquist Bias? It sounds like the title of some sort of action novel, or a spy thriller, or some such. Well, no, it is simply a term from astronomy. It is a special case of what in science we call a selection effect in data. The Malmquist bias is named for the […]
The universe is expanding
Published on 25 Feb 2006 at 7:19 pm.
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Filed under cosmology.
A couple weeks ago, Tom posted an entry about galaxy NGC 1309. Here he mentioned the expansion of the universe, and sort of suggested that I say something about it. Now, I am doing just that.Â
So, to set the story, let’s go back to the early 20th Century. Alexander Friedmann, a Russian mathematician, was working […]
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The Copernican Principle
Published on 16 Feb 2006 at 11:26 am.
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Filed under cosmology.
Back when I was an undergraduate, I took a course entitled “The Philosophy of Science.â€Â As a physics major, this seemed an interesting elective. I wasn’t alone in that feeling, as a bit over half of the class was composed of science and engineering students. There were some interesting things that we talked about in […]
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Dark Matter (part one)
Published on 18 Dec 2005 at 7:48 pm.
5 Comments.
Filed under cosmology, dark matter, physics.
A while back, Tom had suggested dark matter as a blog topic. So, here goes with part one. It is a pretty intense subject, and no one really understands all about dark matter, so it will be the subject of more than one entry.
The story goes back over 70 years. Fritz Zwicky […]
