Context
Earth was hit by a G5 level solar storm triggered by the highly active sunspot region AR13664 unleashing a series of X-class flares and coronal mass ejections (CMEs) directed towards earth.
Coronal Mass Ejections (CMEs)
They are large expulsions of plasma and magnetic field from the Sun’s corona. They can eject billions of tons of coronal material and carry an embedded magnetic field
- The fastest Earth-directed CMEs can reach our planet in as little as 15-18 hours.
Sunspots: Sunspots are the dark areas on the surface of the Sun.
- The dark appearance is because of them being cooler than other parts of the Sun’s surface as they are formed at areas where magnetic fields are particularly strong.
- These magnetic fields are so strong that they keep some of the heat within the Sun from reaching the surface.
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Geomagnetic Storms
- The Sunspot AR 3664: It has grown upto 16-times as wide as the earth combined with AR 3663, making up a cluster much larger than Earth and brimming with magnetic energy.
- The supercharged magnetic fields in such sunspots release a great burst of energy that sends plumes of charged particles called coronal mass ejections (CMEs) together with solar flares (powerful flashes of radiation) into space.
- On May 10, three CMEs struck the earth.
- The present geomagnetic storm: It was categorised as ‘severe’ on Center of Excellence in Space Sciences India (CESSI) scale and is a G5-level solar storm witnessed last in 2003.
- CESSI is the only Indian institute that provides timely updates on space weather.
- Solar storm Measurement: Solar Storms severity is measured on the G-scale, or geomagnetic storm scale ranging from G1 to G5, with each level representing different levels of geomagnetic activity.
- A G1 storm being the lowest level and causing only minor fluctuations in power grids, while a G5 storm could lead to widespread power outages and disruptions in satellite communications.
What caused these Solar Storms?
- The Solar Cycle connection: The 2003 geomagnetic storm event and the present event happened as the Sun was nearing the peak of its solar cycle.
- Earth is currently in Solar Cycle 25, which began in 2020.
- Approaching the Peak: The peak is when the flip (Magnetic Field) actually happens, creating large and magnetically complex sunspot clusters on the solar surface.
- Such large clusters though a usual feature, is accompanied by multiple CMEs resulting in a G5 geomagnetic storm, which usually happens only a couple of times every 11-year solar cycle
The solar cycle:
- It is the cycle that the Sun’s magnetic field goes through approximately every 11 years whereby, the Sun’s magnetic field completely flips ie. the Sun’s north and south poles switch places.
- As the magnetic fields change, so does the amount of activity on the Sun’s surface.
- Impact: The solar cycle affects activity on the surface of the Sun,
- It leads to the formation of Sunspots, which are caused by the Sun’s magnetic fields.
- The charged particles that struck the earth in present are rooted in events at these sunspots.
- Giant eruptions on the Sun, such as solar flares and coronal mass ejections, also increase during the solar cycle. These eruptions send powerful bursts of energy and material into space.
- Tracking Solar Cycle: It is by counting the number of sunspots.
- Solar Minimum: It is the beginning of a solar cycle or when the Sun has the least sunspots.
- Solar Maximum: With time the solar activity and the number of sunspots increases to a peak or when the Sun has the most sunspots.
- End of cycle: After the maximum, it fades back to the solar minimum and then a new cycle begins
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Effects of Solar Storms
- Vulnerability of satellites: Solar Storms can interfere with and threaten the smooth operations of satellites operating in the Low Earth Orbit or LEO (200-1,600km) which are used for multiple purposes, such as navigation, military, intelligence, communications, etc
- Increased Radiation: It can pose health risks to humans, especially airline crew and passengers,on flights at high latitudes, as the amount of solar and cosmic radiation reaching the upper parts of Earth’s atmosphere increases during solar storms.
- Drag effect on satellites: An excessive drag can mean satellites facing intolerable amounts of friction, which in extreme cases can ignite and burn down the satellites, ceasing their operations completely.
- Grid Collapse: A X4-class solar flare in March 1989 accompanied by a CME led to a grid collapse in Quebec and significant effects on the U.S. grid from the Carolinas to California
- Power outages: They can induce geomagnetically induced currents (GICs) to overload electrical systems, leading to voltage regulation problems, transformer damage, and large-scale power outages.
- Example: The fluctuations in the earth’s magnetic field during send currents surging through cables, in Sweden and South Africa in 2003.
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