Our volatile, nearest star
Sunspots
These regions of the Sun are cooler, at temperatures of no more than
4260 degrees Celsius (7,700 degrees Fahrenheit), and shoe the location of strong magnetic fields protruding through what we would see as the solar surface. When there are large, complex sunspot groups they are generally the source of some significant space weather.
Solar wind
A constant outflow of electrons and protons from the Sun that’s always present and buffers Earth’s
magnetic field. The solar wind moves at a speed of approximately
one million miles per hour. On Earth, we have to be aware of space weather, which can influence the performance and reliability of space- and ground-based technological systems, and can endanger life or health
Earth’s magnetic field
Like a bar magnet, the Earth’s magnetic field protects our planet from
the effects of the temperamental Sun. Our planet’s magnetic field is constantly compressed on the day side and stretched out on the night side by the ever-present solar wind. During these geomagnetic storms, the
disturbances to our planet’s magnetic field can become extreme, and in addition to some buffering by the atmosphere, this field also offers some
shielding from the charged particles of a radiation storm.
Geomagnetic storms
A geomagnetic storm is a temporary disturbance of Earth’s magnetic field that’s typically associated
with enhancements in the solar wind. It’s these storms that are created when the solar wind and its magnetic field interacts with Earth’s magnetic field.
Solar flares
Magnetic fields on the surface of the Sun reconnect to drive some of the greatest explosions in our Solar System. These solar flares throw out immense amounts of energy that results in electromagnetic emissions, which span the electromagnetic spectrum from gamma rays to radio waves. Solar flares travel at the speed of light, with emissions covering the distance of 93 million miles to Earth in around eight minutes.
Coronal Mass Ejections (CMEs)
Huge portions of the corona, or outer
atmosphere of the Sun, are often explosively blown into space. This pushes billions of tons of plasma – or superheated
gas – in the direction of our planet. These mass ejections also have their own magnetic field, which slams into and interacts with the Earth’s magnetic field,
resulting in geomagnetic storms. Some CMEs are so fast that they can reach Earth in under a day, with the slowest taking less
than a week to reach us.
Solar radiation storms
Charged particles, including electrons and protons, can be accelerated by coronal mass ejections and solar flares. These particles bounce and weave their way through space, roughly following the magnetic field lines and bombarding Earth from every direction. It’s the fastest of these particles that can affect Earth tens of minutes after a solar flare.
Sun’s magnetic field
It’s the strong and ever-changing magnetic fields that drive the life of the Sun and underlie sunspots. It’s these magnetic fields that are the energy source for space weather, with their twisting, shearing and reconnection that leads to solar flares.