Sunday, October 31, 2010
Sunday, October 24, 2010
1) The homework. The logic behind the homework. Where the heck do some of the numbers come from? What data from the appendices are you supposed to use?
2) The tides are still a little shifty - I have the basic concepts, but not stuff with the CALCULATING the tide/weight/etc problems.
Friday, October 22, 2010
Solar win, earth’s magnetosphere, and electron transitions work together to create something that many people only see in pictures: an aurora. Earth can usually see two auroras, positioned at the north and south poles, called “aurora borealis” and “aurora australis” respectively. Auroras are caused by the fluctuation and motion of the sun’s solar wind, a constant stream of particle extending from the sun’s magnetic field, and the earth’s magnetosphere, the protective shield produced from the magnetic pulls of the earth and centered around the north and south poles. The solar wind moves at a rate of 250 miles per second away from the sun, fast enough to break free of the magnetic field and continue towards earth. As shown in the picture below, the shape of the magnetic field from earth would be less squashed on the side closest to the sun if it weren’t for the solar wind. When the earth’s magnetic field and the sun’s solar wind interact, an aurora can be seen only at the north and south poles, where the magnetic pull of the magnetosphere are most apparent and originate.
When this interaction occurs, electrons and protons from the atmospheric gases smash together, and a display of lights occurs in patterns in the sky between 60-155 miles above the earth. When an atom becomes excited and begins to promote and demote electrons, a light is emitted at various frequencies according to the element. For example, oxygen gives of a greenish yellow light, nitrogen gives off violet-blue light, and at lower altitudes the two gases together give off a bright red. When the three are combined, they create the colors we see in auroras most commonly.
Monday, October 18, 2010
Sunday, October 17, 2010
Monday, October 11, 2010
HELIUM | emission | one of each color except cyan/green