WHAT IS THE SUN?
As we know, the Sun is our main source of energy, it is
an ordinary star that lies about 28,000 light years from
the centre of our galaxy, in one of its spiral arms.
Although the Sun is just a medium sized star compared to
other stars in the galaxy,it is absolutely huge compared
to the planets of our solar system. It's diameter is
approximately 1,392,000 kilometers(865,000 miles), more
than a hundred times of that compared to earth's. The
sun's mass is about 2*10^21 tonnes
(2,000,000,000,000,00,000,000 tonnes). That massive
fireball contains about 99% of the total mass in the
solar system. In the core of the giant, the weight of
the hydrogen pushing down makes the environment dense
and hot enough for hydrogen to be fused together into
helium by a nuclear reaction known as nuclear fusion.
Some of the hygrogen is changed exactly into energy,
and to be exact,the Sun uses up 400 million tonnes of
hydrogen in a second. The amount of energy produced is
so immence that the temperature when the reaction occurs
can reach up yo 15 million degrees celsius.
PARTS OF THE SUN
The outer layer is called the corona, which oooks like a
white halo during a solar eclipse, containing particles
at temperature of millions of degrees. And there is the
yellow surface that we see is called the phrotosphere
and the temperature there is about 5,500 degrees celcius.
Many people think that the sun is a burning rock, but
it's been proved wrong. The Sun is a ball of hydrogen
with a helium core. The outer part of the sun is fusing
and it transports the heat to the phrotosphere for it to
radiate.
SOLAR ACTIVITIES
Many solar activities occur in the sun, like sunspots
and Solar flares. Sunspoits are caused by strong
magnetic force in the Sun and can last for many months,
but one normally disappear in 10 days or so. They
usually occur in groups, but individual spots can
measure kilometres across. These spots are darker but as
bright as full moons.Also, they are 1,500 degrees cooler
than the rest of the photosphere. However, solar flares
are the opposite. Flares happen near the sunspots. In
the flare, enormouse amount of energy is given off in
just a few minutes, causing the temperature to rise up
to more than 100 million degrees celsius. These hot
stuffs produce X-Rays, radio waves and clouds of atomic
particles that shoot into space.
WILL THE SUN DIE?
When will the sun exhaust its hydrogen supply?
Scientists have predicted that the sun would still last
for about 5,500 years million years and when it does
die, it will expand a hundred times larger than it is
now and will engulf the earth in the process. The sun's
outer layer of gas will be thrown off to become a shell
of glowing gas, commonly known as a planetary nebula.
The giant's temperature will then fall and become a red
giant. It then shrinks and thereby becomes a white
dwarf. At this point of time, one teaspoonful of the
sun's material would weigh over a tonne as the whole
sun's mass is concentrated in that white dwarf. The
white dwarf cools and as time passes...
[9 major planets]
[Black Hole]
[Comets]
[Mercury]
[Venus]
[Earth]
[Mars]
[Jupiter]
[Saturn]
[Uranus]
[Neptune]
[Pluto]
[Go Home!!]
By TNN & Co.