A powerful solar flare disrupted radio and navigation signals across North America recently.
About Solar Flare
- A solar flare is an intense burst of radiation coming from the release of magnetic energy associated with sunspots.
- Flares are our solar system’s largest explosive events.
- They are seen as bright areas on the sun, and they can last from minutes to hours.
- In a matter of just a few minutes, they heat the material to many millions of degrees and produce a burst of radiation across the electromagnetic spectrum, including from radio waves to x-rays and gamma rays.
- Although solar flares can be visible in white light, they are often more readily noticed via their bright X-ray and ultraviolet emissions.
- Effect of Solar Flare on Earth
- The intense radiation emitted during a solar flare can affect satellite communications, disrupt radio signals, and even pose a risk to astronauts in space.
- Additionally, the increased solar radiation can lead to geomagnetic storms, which may impact power grids and cause auroras (northern and southern lights) at lower latitudes.
What is a Geomagnetic Storm?
- A geomagnetic storm is a major disturbance of Earth's magnetosphere.
- These storms result from variations in the solar wind that produces significant changes in the currents, plasmas, and fields in Earth’s magnetosphere.
- The solar wind conditions that are effective for creating geomagnetic storms are sustained (for several hours) periods of the high-speed solar wind and a southward-directed solar wind magnetic field (opposite the direction of Earth’s field) at the dayside of the magnetosphere.
- The largest such storms are associated with solar coronal mass ejections (CMEs), where a billion tons or so of plasma from the sun, with its embedded magnetic field, arrives at Earth.
Key Facts about Coronal Mass Ejections (CMEs)
- Solar flares are different to 'coronal mass ejections' (CMEs), which were once thought to be initiated by solar flares.
- CMEs are large expulsions of plasma and magnetic field from the Sun’s corona that propagates outward into interplanetary space.
- Although some are accompanied by flares, it is now known that most CMEs are not associated with flares.
- The blast of a CME carries about a billion tons of material out from the Sun at very high speeds of hundreds of kilometers per second.
Q1) What are sunspots?
Sunspots are dark, planet-size regions of strong magnetic fields on the surface of the sun. They can spawn eruptive disturbances such as solar flares and coronal mass ejections (CMEs). These regions of the sun appear darker because they are cooler than their surroundings.