by neufer » Wed May 06, 2009 9:17 pm
http://apod.nasa.gov/apod/ap090506.html wrote:
Explanation: The above fisheye image was taken from Germany last week.
Visible around the entire image edge is the courtyard of Hirsau Abbey,
once a Benedictine Monastery founded in the year 830.
------------------------------------------
http://www.mikebrownsplanets.com/ wrote:
Mike Brown's Planets
Tuesday, May 5, 2009
Encore: Yelping at Saints
<<In medieval paintings, saints and anyone else holy are always depicted with a halo around their heads. Unlike modern halo depictions, which look like a gold ring hovering slightly above the hat line, these medieval halos appear more like a general glow coming from behind the entire head. Whenever I see one of these glowing medieval halos I think about how bright the full moon is.
I have a hypothesis -- totally without the benefit of supporting research, necessary expertise, or, likely, even minor merit -- that the medieval painters painted halos like this because they had seen such halos around their own heads. And I know what the painters saw, because I have a halo around my head, as well.
Here's another experiment to try. Go outside on a bright sunny day and start watching your shadow.
Walk along until you find a place where the shadow of your head is falling on grass. Focus on your head shadow while you continue to walk, letting the background grass blur in you vision. You will gradually notice that there is a diffuse glow around the shadow of your head. It won't be around any other part of your body, and you won't see the slightest hint around anyone else's head. Point out your halo to any else and they will see precisely the same thing: a halo around their own heads and nothing around yours. Everyone is holy to themselves.
In reality what you are seeing is not some sort of corporeal representation of your own ego or a mystical aura of self-realization, but simply a literal trick of lights and shadows. When you are looking at the shadow of your own head, you are looking, by necessity, directly in the opposite direction of the sun. Stop focusing on your glowing halo for a minute and now focus on the grass itself. You'll notice that in the region where your halo is you will not see a single dark spot due to a shadow of one blade of grass on another. There can't be any shadows; with the sun directly behind you, any piece of grass that you can see can see the sun, so it can't be in shadow. Start looking away from your head shadow and you notice that you are now starting to see collections of tiny shadows, so the overall scene gets darker and darker even though it, too, is fully illuminated by the sun. Your halo is simply the total lack of shadows that can only occur when you are looking almost exactly opposite the sun. I've seen my halo from many places, on many surfaces: on grass or rough dirt or asphalt while walking, even on the tops of a forest full of trees while looking out of the window of an airplane flying low enough right before landing that I could pick out the shadow of the fuselage and see a beautiful glowing ring around. Anywhere you have sunlight and a surface rough enough to make millions of tiny shadows you get to glow the glow of the saints.
And so it is with the moon. When you look at the full moon you are almost looking at where the shadow of you head would be. The sun, though it has set over the horizon, is directly behind you as you face the full moon. If you could see down to the surface of the moon, you wouldn't see a shadow anywhere, not in the craters, not amongst the craggy mountains, but, more importantly not even at the finest scales of the rocky dust that covers most of the surface. The next day, when the moon is just past full, the shadows will begin to reappear and the spotlight will be extinguished.
It happens every month. It's just a trick of light and shadows.>>
[quote=" http://apod.nasa.gov/apod/ap090506.html"]
Explanation: The above fisheye image was taken from Germany last week.
Visible around the entire image edge is the courtyard of Hirsau Abbey,
once a Benedictine Monastery founded in the year 830.[/quote]------------------------------------------
[quote=" http://www.mikebrownsplanets.com/"]
Mike Brown's Planets
Tuesday, May 5, 2009
Encore: Yelping at Saints
<<In medieval paintings, saints and anyone else holy are always depicted with a halo around their heads. Unlike modern halo depictions, which look like a gold ring hovering slightly above the hat line, these medieval halos appear more like a general glow coming from behind the entire head. Whenever I see one of these glowing medieval halos I think about how bright the full moon is.
[list][url=http://en.wikipedia.org/wiki/File:Fra_Angelico_031.jpg][b]St Benedict of Nursia (c. 480-543)[/b][/url], detail from a fresco by Fra Angelico, San Marco, Florence (c. 1400-1455).[/list]
I have a hypothesis -- totally without the benefit of supporting research, necessary expertise, or, likely, even minor merit -- that the medieval painters painted halos like this because they had seen such halos around their own heads. And I know what the painters saw, because I have a halo around my head, as well.
Here's another experiment to try. Go outside on a bright sunny day and start watching your shadow. [b]Walk along until you find a place where the shadow of your head is falling on grass. Focus on your head shadow while you continue to walk, letting the background grass blur in you vision.[/b] You will gradually notice that there is a diffuse glow around the shadow of your head. It won't be around any other part of your body, and you won't see the slightest hint around anyone else's head. Point out your halo to any else and they will see precisely the same thing: a halo around their own heads and nothing around yours. Everyone is holy to themselves.
In reality what you are seeing is not some sort of corporeal representation of your own ego or a mystical aura of self-realization, but simply a literal trick of lights and shadows. When you are looking at the shadow of your own head, you are looking, by necessity, directly in the opposite direction of the sun. Stop focusing on your glowing halo for a minute and now focus on the grass itself. You'll notice that in the region where your halo is you will not see a single dark spot due to a shadow of one blade of grass on another. There can't be any shadows; with the sun directly behind you, any piece of grass that you can see can see the sun, so it can't be in shadow. Start looking away from your head shadow and you notice that you are now starting to see collections of tiny shadows, so the overall scene gets darker and darker even though it, too, is fully illuminated by the sun. Your halo is simply the total lack of shadows that can only occur when you are looking almost exactly opposite the sun. I've seen my halo from many places, on many surfaces: on grass or rough dirt or asphalt while walking, even on the tops of a forest full of trees while looking out of the window of an airplane flying low enough right before landing that I could pick out the shadow of the fuselage and see a beautiful glowing ring around. Anywhere you have sunlight and a surface rough enough to make millions of tiny shadows you get to glow the glow of the saints.
And so it is with the moon. When you look at the full moon you are almost looking at where the shadow of you head would be. The sun, though it has set over the horizon, is directly behind you as you face the full moon. If you could see down to the surface of the moon, you wouldn't see a shadow anywhere, not in the craters, not amongst the craggy mountains, but, more importantly not even at the finest scales of the rocky dust that covers most of the surface. The next day, when the moon is just past full, the shadows will begin to reappear and the spotlight will be extinguished.
It happens every month. It's just a trick of light and shadows.>>[/quote]