Several International Conventions on the Protection of the ozone layer have
produced agreements (Montreal Protocol) by 93 nations to phase out CFC's. Even
so, their presence in the atmosphere is expected to double in the next few decades
because the agreements allow these countries to continue to process CFC's for
a time in order to lessen the impact to the world economy. Also, CFC's released
in the '90's will continue to linger for years. Nevertheless, it is hoped that
the ozone layer will recover completely by the year 2060. More recently, another
area of reduced ozone was discovered over the Northern Hemisphere, presenting
a more dangerous threat to human life as this area is more heavily populated
The outer layers of the Sun exhibit differential rotation: at the equator the
surface rotates once every 25.4 days, near the poles it is as much as 36 days.
This odd behavior is due to the fact that the Sun is not a solid body like the
Earth. Similar effects are seen in the gas planets. This differential rotation
extends considerably down into the interior of the Sun but the core of the Sun
rotates as a solid body.
Because the Sun is so massive in relation to the planets, it exerts a powerful
gravitational pull affecting everything in the solar system. Of course, this
gravitational pull causes the planets, including Earth, to orbit the Sun.
Numerous events occur on the Sun, including:
Sunspots -- magnetic storms that happen on the surface, appearing as dark areas.
Sunspots appear and disappear regularly in eleven-year cycles. Solar flares
-- spectacular discharges of magnetic energy from the corona, sending streams
of protons and electrons into space (sometimes interrupting the communications
network here on Earth).
Solar wind -- the result of gas expansion on the corona, leading to the formation
of ions that are projected outward at the speed of over 500 kilometers per second.
Solar prominences -- columns formed by storms of gas erupting from the surface
that either shoot into space or loop back into the Sun's surface.