What is Space Weather and how does Space Weather Affect the Earth?Find out about the different elements of space weather and how environmental conditions in space affects the Earth.
The most identifiable and visual space weather effect is the auroras (Northern and Southern Lights). However, in addition to these spectacular natural phenomena, space weather also represents a real threat that can and does harm nationwide infrastructure, technology, and communications systems.
What is Space Weather?
Space weather refers to the environmental conditions in Earth's upper atmosphere layers - the magnetosphere, ionosphere and thermosphere, due to the Sun's solar wind energy. The solar wind is a cloud of charged particles which move through space and sometimes into the path of the Earth. When this happens, the charged particles can affect the functioning and reliability of space and ground-based systems and services or endanger property or human health.
What Causes Space Weather?
The source of space weather is the Sun. The Sun is a million times larger than Earth and so far away that its energy takes 8 minutes to reach us. When violent solar phenomena, such as a coronal mass ejection, happen, they create space weather effects on Earth, which will pose a hazard for human activities.
Space weather is the interaction between the Sun, the Earth's magnetic field and the atmosphere. Our location in the solar system is also a factor. The active elements of space weather are charged particles, electromagnetic energy, and magnetic fields, rather than the more often known whether contributors of water, temperature, and air. Magnetic fields, radiation, particles, and matter which have been ejected from the Sun interact with the Earth's magnetic field and upper atmosphere to produce several effects. These effects vary from mild aurora borealis - the northern lights are often seen at high latitudes in the northern hemisphere, to the extraordinary, electric power grids that may experience blackouts or collapse.
Types of Space Weather Event
Space weather is a risk to national infrastructure as it could have a devastating effect on technology. It is even more dangerous to astronauts and the crew of the International Space Station who have little shielding against the space weather.
| Storm Type | Travel Time | Physical Impact | Technological Impact |
|---|---|---|---|
| Geomagnetic | 18-96h | Magnetic currents, increased ionisation in the ionosphere, heating in the thermosphere. | Power grid outages, GNSS, HF comms, satellite electronics, satellite positioning. |
| Charged particles | 10 min to 1 day | Increased radiation levels for astronauts and cabin crew, increased ionisation in the ionosphere | Damage to sensitive electronics, satellite heating, instrument noise, avionics, digital chips, and HF comms out in high latitudes. |
| Solar flares | 8 min | Heating in the thermosphere | HF radio interference, as above |
Dangers of Coronal Holes
Coronal holes are areas of open magnetic field lines where high-speed streams of plasma can flow out from the Sun. If conditions are right, when these particles reach the Earth, geomagnetic storms can happen. High-speed streams interacting with the Earth are the reason for long-lasting (3 or 4 days) periods of geomagnetic activity, particularly within the auroral zone.
Coronal Mass Ejection/Solar Flares
A Coronal Mass Ejection (CME) is the ejection of material from the Sun into interplanetary space. If the material is directed towards the Earth, then the event may result in a disturbance to the Earth's magnetic field and ionosphere.
Solar flares are the sudden releases of energy throughout the entire electromagnetic spectrum. They are hard to predict, and the energy can be detected in Earth's atmosphere as soon as 8.5 minutes after the occurrence of a solar flare.
CMEs are often related to flares. They can take days to reach Earth, carrying a local magnetic field from the Sun, and their arrival time is the focal point of space weather forecasting
Radio Blackouts Caused by Space Weather
The ionosphere is a dynamic part of the upper atmosphere which acts as a reflector for long-range, high-frequency communications. During a solar flare, the rise in x-ray radiation from the Sun causes the ionosphere to absorb rather than reflect signals and this disrupts communications systems on the sun-lit side of the Earth. The Sun may additionally emit radio bursts at more than one wavelength causing more than a few problems for communication and navigation systems.
Space Weather and Auroras
Coronal holes on the Sun's equator and coronal mass ejections give rise to high-speed solar wind streams that buffet the Earth, disturbing the Earth's magnetic field and producing auroras. The charged particles from the solar wind ionise molecules in the atmosphere which we see as the northern lights.
Damage Caused by Solar Weather on Earth
Until the eighteenth century, geomagnetic storms have very little impact on technology. As we depend increasingly more on sensitive electronics and electrical devices, we are more vulnerable to solar weather. The first telegraph outages were reported on 17th November 1848 when the clicker of the telegraph connecting Florence and Pisa behaved unexpectedly throughout a brilliant aurora.
On 13th March 1989, a serious geomagnetic storm brought about a transformer failure on one of the crucial main power transmission lines in the Hydro Quebec system which led, in less than 90 seconds, to the collapse of the entire energy grid. Six million people lost electrical power for 9 or more hours at an eventual cost of over $2 billion.
The same magnetic storm burned up a $36 million transformer in Salem Nuclear plant in New Jersey. These transformers have typical manufacturer lead times of a minimum of one year. Fortunately, a spare transformer from a cancelled nuclear plant in Washington State was to be had, and the Salem plant was in a position to reopen 40 days later.
Space weather will have an enormous impact on humans living on Earth, and as our technological dependence increases, the dangers get larger and larger.
