| So what do we
know about our Sun? Our Sun
is an average
star with a spectral class of G2. It
sits near the center of the main-sequence (which is
a part of a very important diagram called the
Hertzsprung-Russell diagram). It is a big ball of
hydrogen and helium gas that has collapsed to a
point that hydrogen is forced to fuse deep in the
core.
The Sun produces its energy
through what is called the Proton-Proton Chain,
which is the act of nuclear fusion - the fusion of
hydrogen atoms to form a helium atom. The energy
released is E = mc2, the famous Einstein
equation. The Sun converts 600 million metric tons
of hydrogen to helium every second. Regardless, the
Sun is only middle-aged at about 4.6 billion years
old. The Sun maintains its steady burning cycle by a
process called hydrostatic equilibrium. This
means the force of the energy exerted by the core of
the Sun is equal to the amount of gravity collapsing
toward the core.
The Sun does not rotate like a
solid body (because it is not a solid body!). The equatorial regions rotate faster
than the polar regions - this is called
differential rotation. Solar rotation is around
27 days at the equator and around 33 days at the
poles. It is this rotation that is believed to be
the source of Sunspots as well as the sunspot
maximum and sunspot minimum. The Sun has
a 22 year cycle resulting from the twisting of
magnetic fields because of differential rotation.
That cycle is divided by 2 to indicate an 11 year
cycle from average sunspot population to maximum or
minimum.
Sometimes the Sun releases
built-up energy (presumably from the magnetic
fields) in the form of prominences, solar
flares, and coronal mass ejections. These
alterations in the Sun's magnetic field can affect
communications on
Earth. While the
atmosphere safely
filters out the affects of these high energy
phenomenon, astronauts are at risk. However, since
these eruptions have a large distance to travel, we
will have some warning.
 At the speed of light,
photons from the Sun take a little over 8 minutes to
reach us. These ejections do not travel that fast.
At best, these eruptions will allow for some
fantastic appearing
aurora at the North and South
poles here on
Earth. |
