Double whammy
A T3:30am last Saturday, our time, the Sun produced an X-class solar flare, the most powerful type. This one was so strong that it required two different sunspots exploding at the same time to create it, a rare event.
Researchers have observed in the past, however, that widely separated sunspots can explode in tandem. These are called ‘sympathetic solar flares’.
Occasionally, magnetic loops in the Sun’s corona, fasten themselves to two different sunspots, allowing explosive instabilities to travel from one to the other. This seems to be what happened on Saturday.
The combined solar flares created a sizeable coronal mass ejection, or CME, which is when a portion of the Sun’s plasma gets hurled out into space. If the flare is facing Earth, the CME can take days to arrive. This one, however, was travelling much faster than expected and arrived on
Sunday at about 4:30pm, our time.
Brilliant purple auroras were spotted in New Zealand as a major geomagnetic storm raged around the planet, the strongest since 2017. Radio blackouts lasted several hours. If you had any problems with car and gate remotes on Sunday or Monday, this was probably the cause.
Oddly enough, the event caused a 15 per cent drop in the cosmic radiation to which astronauts on the International Space Station are usually exposed. This is because the CME sweeps away the cosmic rays that continually bombard the Earth. The effect is called a ‘Forbush decrease’, named after Scott Forbush, a pioneering American physicist who noted this and many other solar phenomena in the 1930s.
We can expect more such events in the coming months as the solar cycle peaks. Our star is putting on quite a show at the moment.
Another upcoming spectacular from the Sun will be the total solar eclipse that sweeps across the United States, from south-west to north-east, on Monday, April 8.
Oklahoma is deploying the National Guard to monitor the situation, as 100 000 visitors are expected to descend on the
state to watch the event. Some 250 000 visitors are expected to crowd into Pennsylvania.
The cost of accommodation in Niagara Falls, where the moon will block the sun for three and a half minutes, skyrocketed for the eclipse period, from US$100 a night to over US$1 000.
Adding to the excitement is the possibility that a solar flare may occur during the eclipse, which would be visible in the corona of the sun.
The shadow will be moving at over 3 000 kilometres per hour as it crosses America.
Apart from the normal advice to look at the sun only through eclipse glasses, there have been a number of warnings from the authorities, to stock up on water, food and fuel ahead of the eclipse, with some schools in the path of totality being shut.
This is not because of the eclipse itself, but because the influx of tourists will put pressure on transport, emergency and cellphone services.
Finally, we are properly into Autumn now as we passed the equinox on March 20. Our daytime is just under 12 hours. On this Saturday, noon is at 11:59am, and we are one of only a few places in the world today where solar noon is aligned with midday on our clocks.