Comments on: Let the Sun Shine In http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/ Random samplings from a universe of ideas. Mon, 13 Feb 2012 22:30:13 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: CapitalistImperialistPig http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/comment-page-1/#comment-24420 CapitalistImperialistPig Tue, 30 Jan 2007 12:13:43 +0000 http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/#comment-24420 Very nice post! I first noticed the crescent effect when doing some eclipse watching with a crowd of fifth graders during the '99 eclipse. The effect through trees is indeed wierd and spectacular. Very nice post! I first noticed the crescent effect when doing some eclipse watching with a crowd of fifth graders during the ’99 eclipse. The effect through trees is indeed wierd and spectacular.

]]> By: Carl Brannen http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/comment-page-1/#comment-24422 Carl Brannen Tue, 30 Jan 2007 06:15:57 +0000 http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/#comment-24422 Also in Seattle, a warehouse I worked in had holes in the wall threw beautiful images of the sun on to the opposite side of the building. You can just barely see very large sunspots <a href="http://brannenworks.com/sunspot.jpg" rel="nofollow">this way.</a> (And just in case you're wondering, no, I deny drilling any of the various holes. The building was previously used as an iron foundry.) Speculation is that in ancient times, the Arabs surely must have seen sunspots in their tents. And I would think that sunspots would have been clear in the images of the sun on the floors of old churches (where they keep time). Also in Seattle, a warehouse I worked in had holes in the wall threw beautiful images of the sun on to the opposite side of the building. You can just barely see very large sunspots this way. (And just in case you’re wondering, no, I deny drilling any of the various holes. The building was previously used as an iron foundry.) Speculation is that in ancient times, the Arabs surely must have seen sunspots in their tents. And I would think that sunspots would have been clear in the images of the sun on the floors of old churches (where they keep time).

]]> By: Julianne http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/comment-page-1/#comment-24423 Julianne Tue, 30 Jan 2007 03:14:19 +0000 http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/#comment-24423 One of my grad students showed me how you can get the same diffraction effect through your fingers. If you take your two thumbs and press them together side by side, there's a little gap between the two knuckles. If you narrow the gap as much as possible while looking through them, you'll see vertical lines, due to the same effect. But having entire curtains do that must be cool! One of my grad students showed me how you can get the same diffraction effect through your fingers. If you take your two thumbs and press them together side by side, there’s a little gap between the two knuckles. If you narrow the gap as much as possible while looking through them, you’ll see vertical lines, due to the same effect.

But having entire curtains do that must be cool!

]]> By: Magnus http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/comment-page-1/#comment-24424 Magnus Tue, 30 Jan 2007 02:09:32 +0000 http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/#comment-24424 Thats cool, but my curtains is even cooler. They demonstrate the wave nature of light. I have some semi-transparent curtains in some synthetic textile. One time I noticed that the streetlights shining through the curtains was broken up into rectangular patterns of dots. I figured out that this can only be due to diffraction. Even though the textile is a very course diffraction grating, it could bend the light a small angle so it was noticeable. Thats cool, but my curtains is even cooler. They demonstrate the wave nature of light. I have some semi-transparent curtains in some synthetic textile. One time I noticed that the streetlights shining through the curtains was broken up into rectangular patterns of dots. I figured out that this can only be due to diffraction. Even though the textile is a very course diffraction grating, it could bend the light a small angle so it was noticeable.

]]> By: Jonathan Lubin http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/comment-page-1/#comment-24421 Jonathan Lubin Mon, 29 Jan 2007 20:36:50 +0000 http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/#comment-24421 Somehow, I don’t think that’s so much a physical phenomenon as a geometric one. I pointed out to a professional photographer friend of mine once that when you bring the flood light closer to your subject, the shadows get less sharp, and he had trouble believing me, till he tried out for himself. Somehow, I don’t think that’s so much a physical phenomenon as a geometric one. I pointed out to a professional photographer friend of mine once that when you bring the flood light closer to your subject, the shadows get less sharp, and he had trouble believing me, till he tried out for himself.

]]> By: Philip Rodrigues http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/comment-page-1/#comment-24425 Philip Rodrigues Mon, 29 Jan 2007 17:56:16 +0000 http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/#comment-24425 I remember seeing the same effect as Sean mentions during the solar eclipse in 1999, but on thinking about it later, I assumed I had just been imagining it. It's nice to think I *should* have believed my eyes then :-) I remember seeing the same effect as Sean mentions during the solar eclipse in 1999, but on thinking about it later, I assumed I had just been imagining it. It’s nice to think I *should* have believed my eyes then :-)

]]> By: B http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/comment-page-1/#comment-24431 B Mon, 29 Jan 2007 15:10:01 +0000 http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/#comment-24431 hmm. i never close my blinds. so, in your honor I just attempted to let them down since the sun is shining very nicely today up here in waterloo. the only thing that happened was that the whole thing came down, leaving three holes in the wall and dust on my desk. well, already in college i've always managed to mess up every possible experiment. very nice post btw :-) hmm. i never close my blinds. so, in your honor I just attempted to let them down since the sun is shining very nicely today up here in waterloo. the only thing that happened was that the whole thing came down, leaving three holes in the wall and dust on my desk.

well, already in college i’ve always managed to mess up every possible experiment.

very nice post btw :-)

]]> By: Sean http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/comment-page-1/#comment-24426 Sean Mon, 29 Jan 2007 13:57:48 +0000 http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/#comment-24426 I was once walking through a courtyard at MIT, and looked down to notice thousands of little crescents flittering on the sidewalk. It was, of course, the pinhole-camera effect caused by the leaves of the trees above -- but during a partial solar eclipse! Beautiful and dramatic. I was once walking through a courtyard at MIT, and looked down to notice thousands of little crescents flittering on the sidewalk. It was, of course, the pinhole-camera effect caused by the leaves of the trees above — but during a partial solar eclipse! Beautiful and dramatic.

]]> By: Sherri http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/comment-page-1/#comment-24427 Sherri Mon, 29 Jan 2007 12:00:21 +0000 http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/#comment-24427 The sun does not appear round at sunset sometimes even without these buildings and such in the way. In that case, it's an effect of refraction in the atmosphere. The sun does not appear round at sunset sometimes even without these buildings and such in the way. In that case, it’s an effect of refraction in the atmosphere.

]]> By: Samuel http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/comment-page-1/#comment-24428 Samuel Mon, 29 Jan 2007 11:21:23 +0000 http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/#comment-24428 It is a beautifull phenomena. I was embarassed (but did not show, I hope) by an engineer who told me the spot was actually the Sun. Of course! I should know better. After all I knew the concept of the pinhole inverted image in a camera. I wonder if it is possible, in a dark room, to see some Sun spot. I never had the chance to try. Is it possible? It is a beautifull phenomena. I was embarassed (but did not show, I hope) by an engineer who told me the spot was actually the Sun. Of course!
I should know better. After all I knew the concept of the pinhole inverted image in a camera.
I wonder if it is possible, in a dark room, to see some Sun spot. I never had the chance to try. Is it possible?

]]> By: Amara http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/comment-page-1/#comment-24430 Amara Mon, 29 Jan 2007 08:15:50 +0000 http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/#comment-24430 It's _very_ cool. And why not let yourself be a window blind? If you interlock your hands <a href="http://www.amara.com/turkeyeclipse/InterlockingHands3_med.jpg" rel="nofollow"> like this</a>, then, if you are in a special place at a special time, you might see <a href="http://www.amara.com/turkeyeclipse/InterlockingHands1_med.jpg" rel="nofollow">THIS</a>. I took these snapshots in Cappadochia, Turkey last March 29 from a hilltop where I and my new friends were watching the total solar eclipse. These Turkish boys were watching what we were doing with our interlocking hands, and wanted to try it out too. What fun! It’s _very_ cool. And why not let yourself be a window blind? If you interlock your hands like this, then, if you are in a special place at a special time, you might see THIS. I took these snapshots in Cappadochia, Turkey last March 29 from a hilltop where I and my new friends were watching the total solar eclipse. These Turkish boys were watching what we were doing with our interlocking hands, and wanted to try it out too. What fun!

]]> By: jay http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/comment-page-1/#comment-24429 jay Mon, 29 Jan 2007 07:56:19 +0000 http://blogs.discovermagazine.com/cosmicvariance/2007/01/29/let-the-sun-shine-in/#comment-24429 Julliane, at least you figured it out for youself. I came to know this only after I read a book by Minnaert which was about light and color. I felt quite stupid about not noticing such an obvious thing. Fortunately or unfortunately I was not the only one who was struck by this. ;-) The must be something wrong with our physics education. Shouldn't we start from familiar phenomena happening around us? Julliane, at least you figured it out for youself. I came to know this only after I read a book by Minnaert which was about light and color. I felt quite stupid about not noticing such an obvious thing. Fortunately or unfortunately I was not the only one who was struck by this. ;-) The must be something wrong with our physics education. Shouldn’t we start from familiar phenomena happening around us?

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