SUN GENERAL INFORMATION

INTRO:
       
    One of the most important features of every day life is the sun. 
It rises and sets, and we use it to fix our daily routine. Without it
we would not receive the light and heat that provides us with energy.
This star, our sun, is very unique. Most stars are visible only at 
night, but our sun is visible at daytime. It is the closest star to 
earth. Since the star is so close to us, we are able to know much about
its surface. Similar to all stars, the sun is a ball of hot gas. It 
has an interior as well as an atmosphere. The sun's surface is known 
as the photosphere. It's surface is largely uniform in brightness and 
becomes slightly darker on its edges. The sun is onr of our sources of 
energy. Nuclear fusion is the process by which energy in the sun is 
formed. Groups of four hydrogen atoms are changed in to a single helium
atom.

THE SUN AND US:

    The sun is a star located at the center of our solar system. Although 
we can see many stars at night, the sun is the only one that we can see 
during the day. The sun is the biggest object in the solar system, as 
well as the most important. It's gravity keeps the planets from spinning 
off in to space.
    The sun is also important for our life on Earth. It provides us with
food, wind, weather, and tides. It contributes power for our factories by
running windmills and hydropower. The sun also provides us with 
electricity that is generated by fossil fuels, such as coal, gas, and oil.
These fuels are nothing more than stored sunlight. Solar energy does not
pollute, is almost free, and will not run out for some five billion
years.
    Our bodies are provided with energy from the sun as well. It 
triggers photosynthesis to occur in green plants. The process traps 
the sun's energy and turns it in to carbohydrates. By eating these 
plants, animals convert this energy in to a type they can use. These 
carbohydrates are passed up the food chain.
    The sun plays an important role in our weather. The sun's rays hit
the ground and the warm ground heats the air above. Warm air from the 
equator moves north and south to the poles, making winds. The sun warms 
the oceans, and makes water vapor. The vapor rises and forms clouds. 
When the droplets are large enough, they fall back down to the earth 
as rain, sleet, snow or hail.

LAYERS OF THE SUN:

    Close up, our sun is not as amiable. Its outer layers are extremely
hot, bubbling, and full with explosions. The first layer, the 
photosphere, looks like the sun's surface. In the photosphere, hot 
gases rise and cool. These are known as convective cells. Upon reaching 
the surface, they look like small freckles, known as granules. The 
temperature of the photosphere is about 10,000 degrees Fahrenheit, 
which is much cooler than what is above and below. But it is the 
photosphere that sends heat and light in to space. These waves travel 
at 186,300 miles per second, and reach Earth within approximately 
eight minutes.
    The next layer is the chromosphere. The best time to see this layer
is during a total eclipse, which is when the moon blocks the sun's disk. 
The chromosphere appears as a thin, pink ring around the edge of the sun.
The bottom part of the sun's atmosphere is irregular in terms of its 
shape. Its depth can vary from 1,000 to 10,000 miles. Giant flames, 
or spicules, make the chromosphere irregular. Spicules are made of hot 
gases that shoot from the chromosphere in to less dense area. They can 
extend up to 10,000 miles and travel at 17 miles per second.
   The corona is also best studied during a total eclipse. It appears 
as a pearl white layer extending out around the sun. The corona is the 
top layer of the sun's atmosphere. It is made up of very hot, thin 
gases and stretches more than 1 million miles from the photosphere. 
Its one million degrees hotter than the sun's surface due to violent 
explosions from below, such as sunspots, prominences, or solar flares. 
With these high temperatures, the corona is constantly expanding and 
changing shape.

SUNSPOTS:

    Sunspots are cooler, darker areas in the photosphere that appear 
to be dark blemishes on the sun's surface. In 1610, Galileo used his 
telescope to watch these sunspots. His findings made the Roman 
Catholic Church very upset, for they believed that God's creations 
had no imperfections. Today, we know that sunspots are not merely 
imperfections, but in fact they are daily solar events. They seem 
to be darker because they are cooler than the other gases, even though 
they are still very hot, almost 7,000 degrees Fahrenheit. They can 
range from 500 to 50,000 miles in diameter. Sunspots have a dark 
center, called its umbra and a less dark region, called it's penumbra. 
Sunspots may appear alone or in groups of over one hundred, lasting 
for either a few hours or as long as eighteen months. On average, a 
sunspot lasts about a week.
    Scientists have not yet been able to fully understand where they 
come from or their purpose for existence. What they do know is that 
the sun has a strong magnetic field. When these magnetic forces break 
through the photosphere, sunspots appear. Magnetic forces slow down 
the vibration of gas atoms, making these areas cooler and darker than 
the surroundings.
    In 1843, astronomer Samuel Heinrich Schwabe, noticed that sunspots
appear in cycles. A few sunspots, is called a solar minimum. When there 
are many sunspots, it is called a solar maximum. The periods between 
maximums can average almost eleven years but can vary from seven to 
seventeen.

PROMINENCES:

    When a sunpots's magnetic forces erupt in to space, hot gases 
are carried with them. These flaming arches are called prominences. 
Prominences extend in to the corona and loop back. Most are about 
100,000 miles long an 3,000 miles thick. They can soar as high as 
two million miles above the surface, traveling at about 100 miles 
per second. Some may move as fast as 830 miles per second. Prominences 
are best seen during a total solar eclipse.

SOLAR FLARES:

    Solar flares are one of the most spectacular sights of the sun. 
Flares are explosions caused by magnetic forces on the sun's surface. 
A flare may only last a few minutes but it can be as powerful as ten 
million hydrogen bombs. A big flare can produce enough energy to supply 
one of our major cities with electricity for 200 million years.
    A flare sends billions of tons of solar matter in to space, along 
with light, heat, and radiation. Particles of matter are carried by 
the solar wind. Solar wind blows even harder after a flare, but is 
constantly moving. It can carry one million tons of the sun in to 
space every second at a speed of 200 to 500 miles per second. Solar 
wind can not be seen, but can be felt. NASA has designed a solar sail 
that can use solar wind to push a spacecraft between planets without 
an engine.

EFFECTS OF SOLAR ACTIVITY:

    Solar activity affects our life on Earth. Solar flares send out 
many atomic particles in to space, which reach Earth within two days. 
The Earth is surrounded by our own magnetic field that mostly deflects 
the incoming electrons. Some of these electrons get trapped inside 
the magnetic field and instead, circle the Earth. Upon reaching the 
poles, where the field is the weakest, the electrons sink in to the 
atmosphere and collide with nitrogen or oxygen atoms. The electrical 
current that is created, makes a curtain of red and green light, also 
called an aurora. It may be aurora borealis, northern lights, or 
aurora australis, southern lights, depending on which pole. Sometimes 
it can be seen from as far as Texas or Florida.
    A powerful flare can hit Earth with many particles. This is known 
as solar storms. They can knock out electric power stations, interrupt 
radio signals, and cause compasses to spin. In 1972, a solar flare 
caused a 230,000 volt transformer in British Columbia to explode. In 
1989, parts of Montreal were blacked out for nine hours. There were 
also reports of garage doors opening and closing on their own.

FOR MATURE AUDIENCE ONLY... DEATH OF THE SUN:

    The sun exists because of fusion. Every second it turns 600 million 
tons of hydrogen in to helium and energy. Scientists estimate that the 
sun has enough fuel to last another five billion years. After that, the 
sun will not have the force of fusion pushing out, making it hard to 
resist its own gravity pulling in, causing it to collapse. The atoms 
will fall toward each other, faster and faster, just as when the sun 
was created. This time, it will be helium fusion, which releases more 
energy than hydrogen fusion, making the sun hotter and causing it to 
expand. By this point, the sun would be a very large and red object. 
It will burn almost one thousand times more brightly. The outer layers 
will swell even bigger and may sallow up Mercury, Venus and possibly 
even Earth.
    This new red sun will use its helium fuel within a million years 
and the outer layers will expand in to space, leaving behind a bare 
core about the size of Earth. This star, called a white dwarf, will 
burn blue at 216,032 degrees. It will be very dense and the atoms will 
be packed so tightly that a cubic inch will weigh over a ton. It will 
be very bright. Over the next several billion years, the white dwarf 
will burn out and cool off. That will be the end of the sun. Before 
that, with the new technology, maybe humans will find a new star that 
can provide warmth, food and protection for another few billion years. 
We still have five billion years to make new discoveries and enjoy what 
our sun has to offer today.