Extract from ABC News
On Friday, the Bureau of Meteorology warned a severe geomagnetic storm event was expected to impact Earth from about 8pm AEST.
Power outages could occur and satellite services could be impacted.
The BOM urged governments and critical infrastructure operators to take action to reduce potential impacts on infrastructure and essential services, such as power grids.
Geomagnetic storms are not considered dangerous to human bodies.
Level G4 (severe) geomagnetic storm conditions were expected to arrive at Earth from about 8pm AEST on Friday before reducing to G3, with a chance of reaching level G4 again on Saturday.
The G-scale is a measure of global geomagnetic activity, which refers to fluctuations in Earth's magnetic field across the globe. The G-scale ranges from G1 (minor) to G5 (extreme).
The BOM predicts these geomagnetic conditions will likely continue until 6am on Monday.
If G4 geomagnetic conditions occur, bright auroras will be visible at unusually low latitudes, including dark-sky locations near Sydney and Perth.
"To view auroras, you ideally need a dark night with little cloud cover and an unobstructed view to the south," the BOM posted on Facebook at 7pm AEST on Friday.
"Bright auroras usually last for 1-3 hours and the best viewing time is around midnight — between 10pm and 2am."
The intensity of geomagnetic storms in Australia is usually lower than the planetary average.
The BOM says this event is a result of four coronal mass ejections observed at 3:36pm AEST and 10:24 pm AEST on Wednesday, and at 8.24am AEST and 7.36pm AEST on Thursday.
Coronal mass ejections occur when large clouds of plasma and magnetic field erupt in the Sun's outer atmosphere, according to the Australian Space Weather Alert System.
When the mass ejections hit Earth, they cause geomagnetic storms.
The US National Oceanic and Atmospheric Administration says a severe magnetic storm includes the potential for an aurora to be seen in states as far south as Alabama and northern California.
Auroras may also be visible in the UK, as far south as Liverpool.
"Where skies are clear and provided dark enough skies, sightings are expected to develop following the [coronal mass ejections] arrival across the northern half of the UK, with a chance that aurora may become visible to all parts of the UK and similar geomagnetic latitudes," the UK's Meteorological Service office said in an update on its website.
According to the BOM, geomagnetic storms of G4 level can potentially disrupt:
- critical infrastructure such as power grids, causing power outages
- satellite services, affecting communications and global position, navigation and timing services that use high-frequency radio communication.
The BOM will continue to monitor the situation.
No comments:
Post a Comment