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	<title>Comments on: What causes the seasons?</title>
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	<link>http://www.sciencebase.com/science-blog/what-causes-the-seasons.html</link>
	<description>Science Blog from Freelance Science Writer David Bradley</description>
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		<title>By: Brian Cox</title>
		<link>http://www.sciencebase.com/science-blog/what-causes-the-seasons.html/comment-page-2#comment-636711</link>
		<dc:creator>Brian Cox</dc:creator>
		<pubDate>Sat, 20 Mar 2010 11:53:43 +0000</pubDate>
		<guid isPermaLink="false">http://www.sciencebase.com/science-blog/?p=5284#comment-636711</guid>
		<description>ha ha ! Yes, I hadn&#039;t thought about the self-interest part of the virgins myth!</description>
		<content:encoded><![CDATA[<p>ha ha ! Yes, I hadn&#8217;t thought about the self-interest part of the virgins myth!</p>
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		<title>By: David Bradley</title>
		<link>http://www.sciencebase.com/science-blog/what-causes-the-seasons.html/comment-page-2#comment-636710</link>
		<dc:creator>David Bradley</dc:creator>
		<pubDate>Sat, 20 Mar 2010 11:29:43 +0000</pubDate>
		<guid isPermaLink="false">http://www.sciencebase.com/science-blog/?p=5284#comment-636710</guid>
		<description>That myth about virgins not being able to get to Heaven sounds like a clever bit of self-interest on the part of Norsemen though, doesn&#039;t it?</description>
		<content:encoded><![CDATA[<p>That myth about virgins not being able to get to Heaven sounds like a clever bit of self-interest on the part of Norsemen though, doesn&#8217;t it?</p>
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		<title>By: David Bradley</title>
		<link>http://www.sciencebase.com/science-blog/what-causes-the-seasons.html/comment-page-1#comment-636709</link>
		<dc:creator>David Bradley</dc:creator>
		<pubDate>Sat, 20 Mar 2010 11:22:51 +0000</pubDate>
		<guid isPermaLink="false">http://www.sciencebase.com/science-blog/?p=5284#comment-636709</guid>
		<description>@Brian Thanks for your comments on the post. Point taken. I&#039;m really enjoying the series, so apologies for any offence. It just seemed that one graphic stood out as likely to confuse. Others seemed to agree that it was an odd representation, although that discussion on John Gribbin&#039;s Facebook page seems to have disappeared.</description>
		<content:encoded><![CDATA[<p>@Brian Thanks for your comments on the post. Point taken. I&#8217;m really enjoying the series, so apologies for any offence. It just seemed that one graphic stood out as likely to confuse. Others seemed to agree that it was an odd representation, although that discussion on John Gribbin&#8217;s Facebook page seems to have disappeared.</p>
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		<title>By: Brian Cox</title>
		<link>http://www.sciencebase.com/science-blog/what-causes-the-seasons.html/comment-page-1#comment-636707</link>
		<dc:creator>Brian Cox</dc:creator>
		<pubDate>Sat, 20 Mar 2010 10:42:25 +0000</pubDate>
		<guid isPermaLink="false">http://www.sciencebase.com/science-blog/?p=5284#comment-636707</guid>
		<description>And one more, while I&#039;m irritated. 

The Northern Lights / spirits issue has also attracted a lot of comment. In the full piece to camera, I  recount a Norse myth that our guide told me about the origin of the Aurora. The myth is that if a woman dies as a virgin,her spirit cannot pass from Earth to Heaven, and is trapped in-between. I thought it was a nice bit of mythology, so I told the story. The only bit that made it into the final cut was the last sentence. I do have editorial control over these things, so I could have insisted that either the full story was included or the thing was cut, but I decided that it was harmless enough and let it go. But I assure you I am not about to convert to Odin Worship, or whatever! 

Brian</description>
		<content:encoded><![CDATA[<p>And one more, while I&#8217;m irritated. </p>
<p>The Northern Lights / spirits issue has also attracted a lot of comment. In the full piece to camera, I  recount a Norse myth that our guide told me about the origin of the Aurora. The myth is that if a woman dies as a virgin,her spirit cannot pass from Earth to Heaven, and is trapped in-between. I thought it was a nice bit of mythology, so I told the story. The only bit that made it into the final cut was the last sentence. I do have editorial control over these things, so I could have insisted that either the full story was included or the thing was cut, but I decided that it was harmless enough and let it go. But I assure you I am not about to convert to Odin Worship, or whatever! </p>
<p>Brian</p>
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	<item>
		<title>By: Brian Cox</title>
		<link>http://www.sciencebase.com/science-blog/what-causes-the-seasons.html/comment-page-1#comment-636706</link>
		<dc:creator>Brian Cox</dc:creator>
		<pubDate>Sat, 20 Mar 2010 10:36:11 +0000</pubDate>
		<guid isPermaLink="false">http://www.sciencebase.com/science-blog/?p=5284#comment-636706</guid>
		<description>David, 

I am more than a little irritated by the tone of this article. Let me explain the graphic: 

The camera position is indeed, as you point out, fixed to the Sun. It follows the Earth around in it&#039;s orbit, and one frame is taken every 24 hours. It&#039;s not too difficult to see that as viewed from the Sun the North Pole won&#039;t be visible in December, and the South Pole won&#039;t be visible in June. 

I agree that one would usually think of point at which the Sun is vertically overhead at noon oscillating about the equator between the tropics during the year, but it is equally valid to fix this position center frame (i.e. camera at the Sun). Something has to oscillate, and if this position is fixed in frame then you get the graphic as shown. 

Now you can argue that you don&#039;t like this reference frame (the idea actually came from a NASA tutorial which myself and the production team thought was an unusual and interesting way of showing the seasons pass) but you should have been able to work out what was happening with a little thought. Indeed, I would say that anyone who vaguely understands axial precession would not have jumped to some of the conclusions you did in this article. It was not badly drawn (because it&#039;s correct - the only approximation is that the model had a circular orbit) and I can assure you that I understand solar system dynamics sufficiently well to understand the seasons.    

Brian</description>
		<content:encoded><![CDATA[<p>David, </p>
<p>I am more than a little irritated by the tone of this article. Let me explain the graphic: </p>
<p>The camera position is indeed, as you point out, fixed to the Sun. It follows the Earth around in it&#8217;s orbit, and one frame is taken every 24 hours. It&#8217;s not too difficult to see that as viewed from the Sun the North Pole won&#8217;t be visible in December, and the South Pole won&#8217;t be visible in June. </p>
<p>I agree that one would usually think of point at which the Sun is vertically overhead at noon oscillating about the equator between the tropics during the year, but it is equally valid to fix this position center frame (i.e. camera at the Sun). Something has to oscillate, and if this position is fixed in frame then you get the graphic as shown. </p>
<p>Now you can argue that you don&#8217;t like this reference frame (the idea actually came from a NASA tutorial which myself and the production team thought was an unusual and interesting way of showing the seasons pass) but you should have been able to work out what was happening with a little thought. Indeed, I would say that anyone who vaguely understands axial precession would not have jumped to some of the conclusions you did in this article. It was not badly drawn (because it&#8217;s correct &#8211; the only approximation is that the model had a circular orbit) and I can assure you that I understand solar system dynamics sufficiently well to understand the seasons.    </p>
<p>Brian</p>
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	<item>
		<title>By: David Bradley</title>
		<link>http://www.sciencebase.com/science-blog/what-causes-the-seasons.html/comment-page-1#comment-636623</link>
		<dc:creator>David Bradley</dc:creator>
		<pubDate>Wed, 17 Mar 2010 13:55:33 +0000</pubDate>
		<guid isPermaLink="false">http://www.sciencebase.com/science-blog/?p=5284#comment-636623</guid>
		<description>Ah yes. Prof Cox described the Northern Lights as resembling spirits in the sky...</description>
		<content:encoded><![CDATA[<p>Ah yes. Prof Cox described the Northern Lights as resembling spirits in the sky&#8230;</p>
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	<item>
		<title>By: Jeremy</title>
		<link>http://www.sciencebase.com/science-blog/what-causes-the-seasons.html/comment-page-1#comment-636621</link>
		<dc:creator>Jeremy</dc:creator>
		<pubDate>Wed, 17 Mar 2010 12:01:58 +0000</pubDate>
		<guid isPermaLink="false">http://www.sciencebase.com/science-blog/?p=5284#comment-636621</guid>
		<description>I was thinking more Brilliant!</description>
		<content:encoded><![CDATA[<p>I was thinking more Brilliant!</p>
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	<item>
		<title>By: David Bradley</title>
		<link>http://www.sciencebase.com/science-blog/what-causes-the-seasons.html/comment-page-1#comment-636620</link>
		<dc:creator>David Bradley</dc:creator>
		<pubDate>Wed, 17 Mar 2010 11:53:23 +0000</pubDate>
		<guid isPermaLink="false">http://www.sciencebase.com/science-blog/?p=5284#comment-636620</guid>
		<description>Firrssst we take a test-tube filled with....</description>
		<content:encoded><![CDATA[<p>Firrssst we take a test-tube filled with&#8230;.</p>
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	<item>
		<title>By: Jeremy</title>
		<link>http://www.sciencebase.com/science-blog/what-causes-the-seasons.html/comment-page-1#comment-636619</link>
		<dc:creator>Jeremy</dc:creator>
		<pubDate>Wed, 17 Mar 2010 11:31:31 +0000</pubDate>
		<guid isPermaLink="false">http://www.sciencebase.com/science-blog/?p=5284#comment-636619</guid>
		<description>Why am I reminded so strongly of The Fast Show?</description>
		<content:encoded><![CDATA[<p>Why am I reminded so strongly of The Fast Show?</p>
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