Space weather – a short guide

I am a space weather research scientist at the Met Office*, the national meteorological service for the United Kingdom. My job is to transition basic research to operational forecasting- in other words, I try to improve space-weather forecasts with new-and-improved science!

What do I mean by space weather? It basically describes the changing environmental conditions in near-Earth space. Magnetic fields, radiation, particles, and matter, which have been ejected from the Sun, can interact with the Earth’s upper atmosphere and surrounding magnetic field to produce a variety of effects.

There are streams of particles from the Sun constantly hitting the Earth via the solar wind, but the Earth experiences an increased impact during periods of high solar activity, when solar eruptions can occur in the form of solar flares and coronal mass ejections (CMEs). Solar flares are sudden releases of energy across the entire electromagnetic spectrum. They are hard to predict, and the energy can be detected in the Earth’s atmosphere as soon as 8.5 minutes after a solar flare (travelling at the speed of light). CMEs are often associated with flares, eruptions of large amounts of matter from the solar atmosphere. These can take days to reach Earth, carrying a local magnetic field from the Sun. Considering the short time frame for forecasting of flares compared to CMEs, it’s really important to have accurate alerts for big events. That’s where your help with Sunspotter comes in – by improving our understanding of the active regions that are the source of flares, we can hopefully improve our forecasts!

A solar eruption on 2012 August 12 captured by NASA’s Solar Dynamic Observatory in four different extreme ultraviolet wavelengths- clockwise from upper left 335, 171, 131 and 304 Angstrom wavelengths [Credit: NASA/SDO/AIA/GSFC].

But why do we care about space weather? In our increasingly technologically-dependent society, the impact of solar eruptive events can actually be quite severe. Some key sectors in need of accurate event forecasts include energy, aviation, satellite operation, marine, communications, rail, and defence. For example, interruptions to radio communications and GPS can occur due to eruptions, and power grids can also be disrupted. Particles accelerated during eruptions can also damage spacecraft and degrade electronics, and instruments often have to be switched-off or reset. It is important for satellite companies to receive accurate information on the likelihood of eruptions to ensure as little down-time as possible. In the aviation industry, flight crews, passengers, and onboard electronics are all under direct exposure to higher levels of radiation on transpolar flights. Even astronauts cannot take space walks during these events. Solar-activity monitoring systems are imperative to keep astronauts safe!

Space weather has several effects on near-Earth space; the most recognisable might be the aurorae at high latitudes. Large solar eruptions can cause aurorae to form in even lower latitudes, as far south as the equator in very strong events. This image shows the aurora australis captured by NASA’s IMAGE satellite [Credit: NASA].

There have been a number of events directly related to high solar activity in recent years. For example, during a particularly large event in 1989, the entire power grid of Quebec collapsed, causing a 9-hour blackout which effected 6million people. In December 2006, a powerful flare disrupted satellite-to-ground communications and GPS navigation system signals for about 10 minutes. The eruption was so powerful it actually damaged the solar X-ray imager instrument on the GOES 13 satellite that was taking images of it! An American telecommunications satellite, Galaxy 15, now widely known as ‘zombiesat’, ceased responding to commands in 2010. The manufacturer has theorised that solar activity was responsible for the satellite malfunctioning, although they could not settle on a single root cause. Check out the National Research Council or the Royal Academy of Engineering reports for more information on, and examples of, space weather impacts.

In order to monitor and forecast space weather, we generally use ground-based and satellite instrumentation. The solar surface and atmosphere is observed in near-real time to detect any new active regions that may become the source of large events. These observations, such as the MDI images used in Sunspotter, can help determine whether an eruption may be a threat if it is Earth-directed. The Earth’s atmosphere is also monitored to detect changes related to solar wind variations, as well as short-term impacts of solar eruptions. Ongoing scientific research is crucial to determine the fundamental physical processes involved in driving space weather, such as solar magnetic fields. The more that is known about these processes, the more models can be improved to accurately predict when a flare or eruption will occur. So keep clicking those active regions and help improve our warning systems!

*Disclaimer: all statements in this post are my own, and not those of the Met Office.

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