|Space Weather Starts on the Sun
The Sun's atmosphere (the corona) churns and frequently explodes. Loops of magnetic
fields arc above the surface, laden with clouds of electrified gas called plasma,
the fourth state of matter. Plasma particles are blown away from the Sun in every
direction --the solar wind-- carrying millions of tons of matter at
millions of miles per hour.
|Living in the
Atmosphere of the Sun
To the unaided eye, space appears to be a vast, dark void, and the Sun a tranquil sphere of light. But in fact,
space is not empty. That's because we live in the atmosphere of our dynamic Sun. Our solar
system has the cosmic
equivalent of winds, clouds, storms, and hurricanes -- scientists call it space weather. Just
like weather on Earth, it can be both mild and wild.
|The Solar Wind Generates Amazing, Electric Effects Near Earth
The solar wind pushes and stretches Earth's protective magnetic field into a vast, comet-shaped
region called the magnetosphere. The magnetosphere and Earth's atmosphere protect us from
the solar wind and other solar and cosmic radiations.
There is a lot more to the Sun than just the solar wind. Intense explosions on the Sun, called
solar flares, spew X-rays, gamma rays, and radio waves into space. Huge blasts from
the corona, known as coronal mass ejections (CMEs), are the most violent space weather events.
When the solar wind reaches Earth, only a small percentage of the wind's energy penetrates Earth's
magnetic field. But the energy that does enter is enough to create the brilliant aurora around Earth's
poles and to endanger many of our high technology systems.