Space weather research is the study of how the space between the Earth and the sun changes due to solar activity.
Solar eruptions, such as flares and coronal mass ejections (CMEs), are the most powerful events that can affect our space weather. Solar wind—which is an outflow of particles that is constantly emitted from the sun—may also impact our planet.
A coronal mass ejection is a huge bubble of particles that moves from the sun into the solar system. This bubble of gas has a magnetic field associated with it, and if the Earth is in its path, it interacts with our magnetic field. Particles and radiation from solar eruptions can disrupt telecommunications and GPS navigation systems.
CMEs can also affect our power grid and cause blackouts. We had a big one in 1989, when parts of Canada were without power for 12 hours because induced currents created by the solar storm disrupted the power grid.
Satellites can also be damaged when we have these solar eruptions and solar flares, which can interfere with our radio communications as well. Even astronauts that are on the international space station may receive radiation from solar eruptions, so we need to warn them to go to a safe place if a storm is coming. We want to understand space weather to be able to prevent some of this damage.
Space weather research is a relatively new area of investigation, and there are many things that we don’t know. We cannot predict exactly when one of these solar eruptions is going to happen. We can have an idea where on the sun it originates, but we still don’t know when it’s going to happen, if it will reach Earth, or how long it’s going to take to get here.
Usually one of these coronal mass ejections takes between one and two days to reach Earth. Even though we can see its origins right away, because electromagnetic waves travel at the speed of light, we can have an error of more than 12 hours in the predicted arrival time. It’s impractical to turn off a satellite for that amount of time, so we need more accurate predictions, and that’s what people are working on right now.
There is a fleet of satellites dedicated to heliophysics, which studies the physics of the sun and its impact on the entire solar system. Some of the satellites are from NASA, some of them are collaborative ventures with other countries.
When a big coronal mass ejection reaches Earth, energetic particles may be beamed toward the poles of our planet. This stream is what causes the aurora borealis. It is one of the beautiful manifestations of space weather.