Space weather
Space weather describes conditions in space that can have an effect on Earth
The most recognisable and visible space weather effect is arguably the auroras (Northern and Southern Lights). However, as well as these spectacular natural phenomena, space weather also represents a real threat and can have an impact upon national infrastructure, technology, and communications systems.
These effects can include interruptions to radio communications and GPS, disruption of power grids, and damage to spacecraft. The impacts are caused by magnetic fields, radiation, particles and matter which have left the surface of the sun and interacted with the Earth's upper atmosphere and magnetic field.
The Met Office Space Weather Operations Centre (MOSWOC) provides critical information to help build the resilience of UK infrastructure and impacted industries in the face of space weather events.
What causes space weather?
Space weather is a consequence of the behaviour of the Sun, the nature of Earth’s magnetic field and atmosphere, and our location in the solar system. The active elements of space weather are particles, electromagnetic energy and magnetic fields, rather than the more commonly known weather contributors of water, temperature and air. Magnetic fields, radiation, particles and matter which have been ejected from the Sun can interact with the Earth’s magnetic field and upper atmosphere to produce a variety of effects
Types of space weather event
Space weather conditions vary. Streams of particles from the Sun carried by the solar wind constantly hit the Earth. During periods of high solar activity, when there are more solar flares and coronal mass ejections (CMEs), Earth experiences increased impacts. Extreme events that cause the largest impacts can occur at any time during the 11 year solar cycle.
Coronal mass ejection/Solar flares
A 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 across 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 associated with flares. They can take days to reach Earth, carrying a local magnetic field from the Sun, and their arrival time is the focus of space weather forecasting.
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