Now the SUN’S GONE INTO lockdown!
On the solar Reduced activity of a sparked fears surface has ice age. So doomsday mini saw is it time we the light?
BIG news this week about the giant, burning, boiling, spinning thermonuclear reactor which lies 93 million miles away from Earth but is our primary source of life-giving heat and light.
And one might be forgiven for hoping — after weeks of lockdown, far too many deaths, a largely hobbled workforce and an economy spiralling deep into recession — that it might be good news.
Forecasts of a lovely, long, blueskied barbecue summer to perk up our enforced staycations, perhaps? Or, at the very least, a spot of predictable, settled weather to keep our battered spirits afloat. Sadly, not. Because it turns out that even the sun has gone into a lockdown ‘recession’. Or, more accurately, a deep period of ‘solar minimum’.
Which means that the activity on the sun’s surface has fallen dramatically, and its magnetic field has become weaker, letting into the environment more of the sort of cosmic rays that cause dramatic lightning storms and interfere with astronauts and space hardware.
They can also lead to the explosion of ‘sprites’ — clusters of orange and red lights that shoot out of the top of thunderstorms like 90km-high palm trees in the sky.
Oh yes, and on top of all that, theoretically it could cause the temperature on Earth to drop to potentially catastrophic new lows.
While weather forecasters and astronomers are urging us not to panic and reminding us that this is just nature, nothing to worry about and the sort of thing that happens every 11 years or so as the sun passes through its activity cycle, some of the more doom-and-gloom warners are much less optimistic.
PERHAPS they’re haunted by the extreme ‘solar minimum’ thought to have contributed to the so-called Little Ice Age in Europe in the 17th and 18th centuries, when the temperatures fell so low the River Liffey froze over, crops failed, lightning storms lit up the skies, and — in 1816 — the weather was so crazy that it snowed in July.
As we all know, the sun — which is 4.5 billion years old and more than a million times bigger than the Earth — is not only a source of cheer when it finally pops out from behind the clouds, it also keeps us all alive.
Which means that the teeniest change in its activity levels can have extraordinary consequences — triggering lightning storms, the appearance or disappearance of the Northern Lights and those amazing sprites.
But the sun’s activity is changing constantly as it passes through its regular cycle, from solar maximum (hottest and most active) to solar minimum (quieter and cooler).
Since the 17th century, scientists have been measuring the depth of a solar minimum by counting the ‘sunspots’ — areas of magnetic activity on the solar surface which show up as relatively dark spots — and solar flares, large explosions that hurl charged particles into space.
The general rule is the fewer the sunspots, the more severe the minimum and the higher the chances of lightning storms, sprites and disruption on Earth.
So far this year, the sun has been ‘blank’ — with no sunspots — 76% of the time. A figure surpassed just once since the 1950s, last year, when it was 77% blank.
So could we be heading for a grand solar minimum, a sustained period — with decades, or even centuries — of particularly weak solar cycles? Are we now — on top of everything else — facing another mini ice age?
While it might all sound terribly dramatic and end-ofthe-world-ish, history does tell a salutary lesson.
Two hundred years ago, we were deep in the midst of the Dalton Minimum, which occurred between 1790 and 1830 and was marked by periods of brutal cold.
Temperatures fell by 2C over 20 years, which may not sound much, but had the effect of devastating the world’s food production and causing widespread famine. The misery was then exacerbated by some (unrelated) powerful volcanic eruptions around the world. On April 10, 1815, the secondlargest volcanic eruption in 2,000 years happened at Mount Tambora in Indonesia, killing more than 71,000 people and plunging the temperature still lower, as giant ash clouds blocked the solar rays. The following year became known as the ‘year without a summer’ or ‘eighteen hundred and froze to death’, after snow fell in July and thousands died in the famine, food riots and starvation which spread across Europe. A typhus epidemic made things worse. Before all that came the Maunder Minimum (named after astronomer Walter Maunder), a grand solar minimum which started in 1645, took in the ice fairs on the River Thames during the reign of Charles II and dragged on for 70 years. During this time scientists observed only 50 sunspots — compared to the 40,000 to 50,000 that we would expect during an equivalent period of ‘normal’ activity. So it’s a relief to hear from Mathew Owens, professor of space physics, that history is not about to repeat itself.
WHILE he admits that today’s solar minimum is ‘fairly deep’, he insists that we don’t need to worry about finding ourselves in a mini ice age any time soon. ‘We get a solar minimum every 11 years, so it’s a fairly regular occurrence,’ he says. He also insists it needs putting in context, because any fall in temperature would be minuscule. ‘After all, the last solar minimum, which we had in 2009/10, was the deepest for 100 years, and we didn’t die then!’ Meanwhile, scientist Jeff Knight insists that, while a solar minimum does have an effect — contributing to very slightly colder winters (the last minimum between 2008 and 2010 coincided with some colder than usual winters in Ireland) — it is very small. ‘A solar minimum is likely to affect the global mean temperature, making it cooler, but by barely a 20th of a degree,’ he says. Which also means this is no get-out-of-jail-free card for global warming. ‘Just because we’re in a minimum, it doesn’t mean global warming is going to be arrested or reversed — it has a far more subtle effect than that,’ he insists. Of course, our prime concern is that the sun continues to shine. But happily, given we have so much on our plates at the moment, we can park that worry for another five billion years.