My Study Blog
China
July 23, 2009
There are four types of solar eclipses:
- A total eclipse occurs when the Sun is completely obscured by the Moon. The intensely bright disk of the Sun is replaced by the dark silhouette of the Moon, and the much fainter corona is visible. During any one eclipse, totality is visible only from at most a narrow track on the surface of the Earth.
- An annular eclipse occurs when the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. Hence the Sun appears as a very bright ring, or annulus, surrounding the outline of the Moon.
- A hybrid eclipse (also called annular/total eclipse) transitions between a total and annular eclipse. At some points on the surface of the Earth it is visible as a total eclipse, whereas at others it is annular. Hybrid eclipses are comparatively rare.
- A partial eclipse occurs when the Sun and Moon are not exactly in line and the Moon only partially obscures the Sun. This phenomenon can usually be seen from a large part of the Earth outside of the track of an annular or total eclipse. However, some eclipses can only be seen as a partial eclipse, because the umbra never intersects the Earth's surface.
The match between the apparent sizes of the Sun and Moon during a total eclipse is considered coincidental. The Sun's distance from the Earth is about 400 times the Moon's distance, and the Sun's diameter is about 400 times the Moon's diameter. Because these ratios are approximately the same, the sizes of the Sun and the Moon as seen from Earth appear to be approximately the same: about 0.5 degree of arc in angular measure.
The Moon's orbit around the Earth is an ellipse, as is the Earth's orbit around the Sun; the apparent sizes of the Sun and Moon therefore vary.[3][4] The magnitude of an eclipse is the ratio of the apparent size of the Moon to the apparent size of the Sun during an eclipse. An eclipse when the Moon is near its closest distance from the Earth (i.e., near its perigee) can be a total eclipse because the Moon will appear to be large enough to cover completely the Sun's bright disk, or photosphere; a total eclipse has a magnitude greater than 1. Conversely, an eclipse when the Moon is near its farthest distance from the Earth (i.e., near its apogee) can only be an annular eclipse because the Moon will appear to be slightly smaller than the Sun; the magnitude of an annular eclipse is less than 1. Slightly more solar eclipses are annular than total because, on average, the Moon lies too far from Earth to cover the Sun completely. A hybrid eclipse occurs when the magnitude of an eclipse transitions during the event from smaller than one to larger than one—or vice versa—so the eclipse appears to be total at some locations on Earth and annular at other locations.
The Earth's orbit around the Sun is also elliptical, so the Earth's distance from the Sun varies throughout the year. This also affects the apparent sizes of the Sun and Moon, but not so much as the Moon's varying distance from the Earth. When the Earth approaches its farthest distance from the Sun (the aphelion) in July, this tends to favor a total eclipse. As the Earth approaches its closest distance from the Sun (the perihelion) in January, this tends to favor an annular eclipse.
July 19, 2009
This is a beautiful composition,so I reprint it to share with everybody.
I am thirty-three years old, and I am so happy that I am not a mother. I do not hear a biological clock ticking, only the nerve wrecking ticks of bombs yet to explode. My friends are leaping whenever their cell phones ring. "Where are you? No, you can’t go out. No, I don’t care if all the other children are going". How naïve children are when they tell lies. What mother in Israel now would believe that "all the children are going" anywhere?
And where are the children going? Where will their fears take them? In many places in the world children are afraid of the unknown, of the unreal. You know that you live in a war zone when you realize that the greatest fears of the children are of what they know only too well.
Two years ago, when my younger brother was ten, he came home from school, and as he opened the door he heard the familiar sound of explosion rising from the street he just left behind him. Sitting in front of the television five minutes later, he could see his friend wandering blindly in the street, which was covered with body parts and injured people. The friend’s father, who picked him up from school and took him for a pizza, was killed in front of his eyes. My brother refused to talk about it. "This kid wasn’t really a friend of mine," is all he would say, "I don’t really know him that well". That evening he told my father that he is afraid of Freddy Kruger, a monstrous murderer from a common horror film. My father didn’t know whether to laugh or cry, but I suspect he felt some relief. How good it is to caress your child’s hair and to tell him that Kruger doesn’t really exist.
But the man who exploded himself in the centre of a busy street did exist. And the man who will explode himself in another one of our busy streets in a few years is now my brother’s age. His mother doesn’t have to worry about the dangers which lurk on the way to school. There are no schools anymore. We have demolished them all, when we crushed the infrastructure of the Palestinian Authority. His younger brother was killed when our soldiers exploded their home. Our soldiers exploded their home because his older brother was a "wanted person". Exploding his family’s home was our way to insure that he will soon turn from a wanted person into an unwanted body, torn to a thousand pieces, surrounded by his victims.
The young terrorist to be sleeps now in a tent provided by UNRWA. What is he afraid of? Not much to fear anymore. The worst already took place. But the bulldozers are still around, demolishing the neighbours’ homes. Every day a few new tents join the raw. His mother tells him how they were deported from their home in Latrun in 1967. His grandmother tells him it was nothing compared to what she had to go through when she was driven away from Jaffa in 1948, carrying his screaming mother, then a newborn, in her arms.
My grandmother doesn’t understand her plight. It had never occurred to her to go back to her home in Poland, which she had to flee as a refugee, haunted by the rise of Nazism in Europe. The fact that the Palestinians still talk about Jaffa, she says, just proves that they want to exterminate us. Whenever a suicide bombing strikes our cities, my grandmother calls me and tells me of her secret plan. "I am an old woman, and I have nothing to loose," she says in a conspiratorial tone. "I will wear rags like their women, and go and explode myself in the centre of Nablus. This will teach them a lesson. I will show them what it’s like." I am trying to tell her that they already know what it is like, that the number of their dead is three times bigger than ours, that the fear and terror we spread in their lives is much bigger than ours. But my grandmother doesn’t hear me, because she is crying. "They are not human beings," she says. "What people can do such things, kill children like this?" De-humanised people, I want to answer, but I keep my mouth shut, and think about the child that I don’t want to have.
The child I won’t have will never feel the guilt of being an occupier, or the fear of becoming a victim. I will never tell him not to be scared, when fear is the only rational thing to feel. I will not have to teach him that the Palestinian child is a human being just like him, while everybody else will tell him that it is not so. The child I won’t have will keep sleeping, curled in a secret corner of my mind. The child I will never have is going to be the only safe child in the Middle East.
July 3, 2009
Today, I saw a move names <The Perfect Man>.Hilary duff played the lead.
I like it.Maybe it looks like my family.My home has two kids and a singel mother too.To us,moving from place to place is all in the day's work.I often change schools.Sometimes when I make friends,we move.I'm alone and lonely.I don't make friends because I'm afraid of part.I like alone,because I'm always alone.
I hope that one day I can have a settled house.
