tag:theconversation.com,2011:/id/topics/solar-activity-8650/articlesSolar activity – The Conversation2023-10-06T01:53:35Ztag:theconversation.com,2011:article/2151402023-10-06T01:53:35Z2023-10-06T01:53:35Z6 reasons why global temperatures are spiking right now<figure><img src="https://images.theconversation.com/files/552428/original/file-20231006-27-7ho178.jpg?ixlib=rb-1.1.0&rect=25%2C10%2C3424%2C2286&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/6gVvfQEnWtY">Jonas Weckschmied/Unsplash</a></span></figcaption></figure><p>The world is very warm right now. We’re not only seeing record temperatures, but the records are being broken by record-wide margins.</p>
<p>Take the preliminary September global-average temperature anomaly of 1.7°C above pre-industrial levels, for example. It’s an incredible 0.5°C above the previous record.</p>
<p>So why is the world so incredibly hot right now? And what does it mean for keeping our Paris Agreement targets? </p>
<p>Here are six contributing factors – with climate change the main reason temperatures are so high.</p>
<h2>1. El Niño</h2>
<p>One reason for the exceptional heat is we are in a <a href="http://www.bom.gov.au/climate/enso/#tabs=Pacific-Ocean">significant El Niño</a> that is still strengthening. During El Niño we see warming of the surface ocean over much of the tropical Pacific. This warming, and the effects of El Niño in other parts of the world, raises global average temperatures by <a href="https://www.realclimate.org/index.php/archives/2023/01/2022-updates-to-the-temperature-records/">about 0.1 to 0.2°C</a>.</p>
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<a href="https://theconversation.com/explainer-el-nino-and-la-nina-27719">Explainer: El Niño and La Niña</a>
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<p>Taking into account the fact we’ve just come out of a triple La Niña, which cools global average temperatures slightly, and the fact this is the first major El Niño in eight years, it’s not too surprising we’re seeing unusually high temperatures at the moment.</p>
<p>Still, El Niño alone isn’t enough to explain the crazily high temperatures the world is experiencing.</p>
<h2>2. Falling pollution</h2>
<p>Air pollution from human activities cools the planet and has offset some of the warming caused by humanity’s greenhouse gas emissions. There have been efforts to reduce this pollution – since 2020 there has been an <a href="https://sdg.iisd.org/news/imo-advances-measures-to-reduce-emissions-from-international-shipping/">international agreement</a> to reduce sulphur dioxide emissions from the global shipping industry.</p>
<p>It has been speculated this cleaner air has contributed to the recent heat, particularly over the record-warm <a href="https://climate.copernicus.eu/record-breaking-north-atlantic-ocean-temperatures-contribute-extreme-marine-heatwaves">north Atlantic</a> and Pacific regions with high shipping traffic.</p>
<p>It’s likely this is contributing to the extreme high global temperatures – but only on the order of hundredths of a degree. <a href="https://www.carbonbrief.org/analysis-how-low-sulphur-shipping-rules-are-affecting-global-warming/">Recent analysis</a> suggests the effect of the 2020 shipping agreement is about an extra 0.05°C warming by 2050.</p>
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<a href="https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A smog shrouded road with motorcycles, trucks and cars barely visible through the pollution" src="https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">People pass through the rising pollution on the Delhi-Jaipur Expressway in Gurgaon, Haryana, India, on November 12 2021.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/people-pass-through-rising-pollution-on-2073480677">Shutterstock</a></span>
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<h2>3. Increasing solar activity</h2>
<p>While falling pollution levels mean more of the Sun’s energy reaches Earth’s surface, the amount of the energy the Sun emits is itself variable. There are different solar cycles, but an 11-year cycle is the most relevant one to today’s climate.</p>
<p>The Sun is becoming <a href="https://edition.cnn.com/2023/07/14/world/solar-maximum-activity-2024-scn/index.html">more active</a> from a minimum in late 2019. This is also contributing a small amount to the spike in global temperatures. Overall, increasing solar activity is contributing only hundredths of a degree at most to the recent global heat. </p>
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Read more:
<a href="https://theconversation.com/this-solar-cycle-the-suns-activity-is-more-powerful-and-surprising-than-predicted-209955">This solar cycle, the sun's activity is more powerful and surprising than predicted</a>
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<h2>4. Water vapour from Hunga Tonga eruption</h2>
<p>On January 15 2022 the underwater <a href="https://www.jpl.nasa.gov/images/pia26006-hunga-tonga-hunga-haapai-eruption">Hunga Tonga–Hunga Haʻapai volcano erupted</a> in the South Pacific Ocean, sending large amounts of water vapour high up into the upper atmosphere. Water vapour is a greenhouse gas, so increasing its concentration in the atmosphere in this way does intensify the greenhouse effect.</p>
<p>Even though the eruption happened almost two years ago, it’s still having a small warming effect on the planet. However, as with the reduced pollution and increasing solar activity, we’re talking about hundredths of a degree.</p>
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<h2>5. Bad luck</h2>
<p>We see variability in global temperatures from one year to the next even without factors like El Niño or major changes in pollution. Part of the reason this September was so extreme was likely due to weather systems being in the right place to heat the land surface.</p>
<p>When we have persistent high-pressure systems over land regions, as seen recently over places like <a href="https://www.theguardian.com/environment/2023/oct/01/autumn-heat-continues-in-europe-after-record-breaking-september">western Europe</a> and <a href="https://www.abc.net.au/news/2023-09-19/australia-weather-september-heat-records-tumble/102870294">Australia</a>, we see local temperatures rise and the conditions for unseasonable heat.</p>
<p>As water requires more energy to warm and the ocean moves around, we don’t see the same quick response in temperatures over the seas when we have high-pressure systems.</p>
<p>The positioning of weather systems warming up many land areas coupled with persistent ocean heat is likely a contributor to the global-average heat too.</p>
<h2>6. Climate change</h2>
<p>By far the biggest contributor to the overall +1.7°C global temperature anomaly is human-caused climate change. Overall, humanity’s effect on the climate has been a global warming of <a href="https://www.globalwarmingindex.org/">about 1.2°C</a>.</p>
<p>The record-high rate of greenhouse gas emissions means we should expect global warming to accelerate too.</p>
<p>While humanity’s greenhouse gas emissions explain the trend seen in September temperatures over many decades, they don’t really explain the big difference from last September (when the greenhouse effect was almost as strong as it is today) and September 2023.</p>
<p>Much of the difference between this year and last comes back to the switch from La Niña to El Niño, and the right weather systems in the right place at the right time.</p>
<h2>The upshot: we need to accelerate climate action</h2>
<p>September 2023 shows that with a combination of climate change and other factors aligning we can see alarmingly high temperatures.</p>
<p>These anomalies may appear to be above the 1.5°C global warming level referred to in the Paris Agreement, but that’s about keeping <a href="https://climateanalytics.org/briefings/understanding-the-paris-agreements-long-term-temperature-goal/">long-term global warming</a> to low levels and not individual months of heat.</p>
<p>But we are seeing the effects of climate change unfolding more and more clearly.</p>
<p>The most vulnerable are suffering the biggest impacts as wealthier nations continue to emit the largest proportion of greenhouse gases. Humanity must accelerate the path to net zero to prevent more record-shattering global temperatures and damaging extreme events.</p>
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Read more:
<a href="https://theconversation.com/net-zero-by-2050-too-late-australia-must-aim-for-2035-213973">Net zero by 2050? Too late. Australia must aim for 2035</a>
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<p class="fine-print"><em><span>Andrew King receives funding from the National Environmental Science Program. </span></em></p>The preliminary global-average temperature anomaly for September is a shocking 1.7°C. These are the drivers of current record-breaking heat.Andrew King, Senior Lecturer in Climate Science, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1451012020-09-01T20:00:14Z2020-09-01T20:00:14ZClimate explained: Sunspots do affect our weather, a bit, but not as much as other things<figure><img src="https://images.theconversation.com/files/355268/original/file-20200828-14-tsbpgy.jpg?ixlib=rb-1.1.0&rect=0%2C311%2C1024%2C712&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
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<p><em><strong><a href="https://theconversation.com/nz/topics/climate-explained-74664">Climate Explained</a></strong> is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.</em> </p>
<p><em>If you have a question you’d like an expert to answer, please send it to <a href="mailto:climate.change@stuff.co.nz">climate.change@stuff.co.nz</a></em></p>
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<p><strong>Are we headed for a period with lower Solar activity, i.e. sunspots? How long will it last? What happens to our world when global warming and the end of this period converge?</strong></p>
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<p>When climate change comes up in conversation, the question of a possible link with the Sun is often raised. </p>
<p>The <a href="https://www.nasa.gov/sun">Sun</a> is a highly active and complicated body. Its behaviour does change over time and this <a href="https://climate.nasa.gov/blog/2910/what-is-the-suns-role-in-climate-change/">can affect our climate</a>. But these impacts are much smaller than those caused by our burning of <a href="https://climate.nasa.gov/causes/">fossil fuels</a> and, crucially, they do not build up over time.</p>
<p>The main change in the Sun is an 11-year Solar cycle of high and low activity, which initially revealed itself in a count of sunspots. </p>
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<figcaption><span class="caption">One decade of solar activity in one hour.</span></figcaption>
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<p>Sunspots have been observed continuously since 1609, although their cyclical variation was not noticed until much later. At the peak of the cycle, <a href="https://www.nasa.gov/mission_pages/Glory/solar_irradiance/total_solar_irradiance.html">about 0.1%</a> more Solar energy reaches the Earth, which can increase global average temperatures by <a href="https://iopscience.iop.org/article/10.1088/1748-9326/6/4/044022#erl408263fig7" title="Global temperature evolution 1979–2010">0.05-0.1°C</a>.</p>
<p>This is small, but it can be <a href="https://link.springer.com/article/10.1007/s00382-016-3255-8" title="An empirical model for probabilistic decadal prediction: global attribution and regional hindcasts">detected</a> in the <a href="https://tamino.wordpress.com/2018/10/09/the-global-warming-signal/">climate record</a>. </p>
<p>It’s smaller than other known sources of temperature variation, such as <a href="https://www.theguardian.com/environment/2019/may/30/humans-and-volcanoes-caused-nearly-all-of-global-heating-in-past-140-years">volcanoes</a> (for example, the large eruption of Mt Pinatubo, in the Philippines in 1991, <a href="https://www.livescience.com/14513-pinatubo-volcano-future-climate-change-eruption.html">cooled Earth by up to 0.4°C</a> for several years) and the El Niño Southern Oscillation, which causes variations of up to <a href="https://iopscience.iop.org/article/10.1088/1748-9326/6/4/044022" title="Global temperature evolution 1979–2010">0.4°C</a>. </p>
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Read more:
<a href="https://theconversation.com/climate-explained-how-volcanoes-influence-climate-and-how-their-emissions-compare-to-what-we-produce-125490">Climate explained: how volcanoes influence climate and how their emissions compare to what we produce</a>
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<p>And it’s small compared to human-induced global warming, which has been accumulating at <a href="https://climate.nasa.gov/vital-signs/global-temperature/">0.2°C per decade</a> since 1980.</p>
<p>Although each 11-year Solar cycle is different, and the processes underlying them are not fully understood, overall the cycle has been stable for hundreds of millions of years.</p>
<h2>A little ice age</h2>
<p>A famous period of low Solar activity, known as the <a href="https://www.britannica.com/science/Maunder-minimum">Maunder Minimum</a>, ran from 1645 to 1715. It happened at a similar time as the <a href="https://www.bbc.com/news/science-environment-16797075">Little Ice Age</a> in Europe.</p>
<p>But the fall in Solar activity was too small to account for the temperature drop, which has since been attributed to <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011GL050168" title="Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea‐ice/ocean feedbacks">volcanic eruptions</a>.</p>
<p>Solar activity picked up during the 20th century, reaching a peak in the cycle that ran from 1954 to 1964, before falling away to a very weak cycle in 2009-19. </p>
<p>Bear in mind, though, that the climatic difference between a strong and a weak cycle is small.</p>
<h2>Forecasting the Solar cycle</h2>
<p>Because changes in Solar activity are important to spacecraft and to radio communications, there is a <a href="https://www.swpc.noaa.gov/news/solar-cycle-25-forecast-update">Solar Cycle Prediction Panel</a> who meet to pool the available evidence.</p>
<p>Experts there are currently predicting the next cycle, which will run to 2030, will be similar to the last one. Beyond that, they’re not saying.</p>
<p>If activity picks up again, and its peak happened to coincide with a strong El Niño, we could see a boost in temperatures of 0.3°C for a year or two. That would be similar to what happened during the El Niño of 2016, which <a href="https://journals.ametsoc.org/bams/article/99/1/S1/216139/Explaining-Extreme-Events-of-2016-from-a-Climate">featured</a> record air and sea temperatures, wildfires, rainfall events and bleaching of the Great Barrier Reef.</p>
<p>The <a href="https://www.noaa.gov/news/special-report-2016-extreme-weather-events-and-ties-to-climate-change">extreme weather events</a> of that year provided a glimpse into the future. They gave examples of what even average years will look like after another decade of steadily worsening global warming. </p>
<h2>A journey to the Sun</h2>
<p>Solar physics is an active area of research. Apart from its importance to us, the Sun is a playground for the high-energy physics of plasmas governed by powerful magnetic, nuclear and fluid-dynamical forces.</p>
<p>The Solar cycle is driven by a <a href="https://royalsocietypublishing.org/doi/10.1098/rsta.2011.0507" title="The solar dynamo">dynamo</a> coupling kinetic, magnetic and electrical energy.</p>
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Read more:
<a href="https://theconversation.com/explainer-how-does-our-sun-shine-30917">Explainer: how does our sun shine?</a>
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<p>That’s pretty hard to study in the lab, so research proceeds by a combination of observation, mathematical analysis and computer simulation.</p>
<p>Two spacecraft are currently directly observing the Sun: NASA’s <a href="https://www.nasa.gov/content/goddard/parker-solar-probe">Parker Solar Probe</a> (which will eventually approach to just 5% of the Earth-Sun distance), and ESA’s <a href="https://www.esa.int/Science_Exploration/Space_Science/Solar_Orbiter">Solar Orbiter</a>, which is en route to observe the Sun’s poles.</p>
<p>Hopefully one day we will have a better picture of the processes involved in sunspots and the Solar cycle.</p>
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<figcaption><span class="caption">Exploring the 11-year Solar cycle.</span></figcaption>
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<p class="fine-print"><em><span>Robert McLachlan does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change. If you have a question you’d like an expert…Robert McLachlan, Professor in Applied Mathematics, Massey UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1301542020-01-24T11:46:18Z2020-01-24T11:46:18ZFour graphs that suggest we can’t blame climate change on solar activity<figure><img src="https://images.theconversation.com/files/311600/original/file-20200123-162185-1oweuwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Sun by the Atmospheric Imaging Assembly of NASA s Solar Dynamics Observatory.</span> <span class="attribution"><span class="source">NASA</span></span></figcaption></figure><p>The past decade (2010-2019) was the hottest on record and five of the top 10 warmest single years have all occurred since 2015, according to reports released by the <a href="https://www.metoffice.gov.uk/about-us/press-office/news/weather-and-climate/2020/confirmation-that-2019-concludes-warmest-decade-on-record">UK Met Office</a> and the <a href="https://public.wmo.int/en/media/press-release/wmo-confirms-2019-second-hottest-year-record">World Meteorological Organisation</a>.</p>
<p>The current <a href="https://theconversation.com/australia-your-country-is-burning-dangerous-climate-change-is-here-with-you-now-129569">Australian bushfire crisis</a> is also the <a href="https://www.theguardian.com/australia-news/2020/jan/09/bushfires-crisis-more-than-75-of-australia-had-worst-weather-conditions-on-record-last-month">worst on record</a>, having emerged due to a combination of increased average temperature (roughly 1.5°C above the long term average) and a reduction in rainfall.</p>
<p>But can we attribute this to anything more natural than anthropogenic effects? Solar activity, for example, <a href="http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/solact.html">has previously been linked</a> to temperature and is <a href="https://www.newscientist.com/article/dn11650-climate-myths-global-warming-is-down-to-the-sun-not-humans/">sometimes blamed</a> for climate change. But our new analysis provides evidence for why this isn’t the case.</p>
<p>The sun is the dominant source of energy for the Earth’s climate, so quantifying what influence it has had on global temperatures since industrialisation is very important.</p>
<p>Like all stars, the sun undergoes variations in solar activity, meaning its energy output varies with time. The visible surface of the sun (which you should never look at directly) is called the photosphere. When imaged, it appears as a white disk which is occasionally blotted by the appearance of sunspots. </p>
<p>These sunspots are regions of intense magnetic fields that restrict the movement of gas and cause it to cool, making these areas appear dark. However, these same intense <a href="https://scied.ucar.edu/solar-active-regions-sunspots-uv-image">magnetic fields connect</a> the visible sunspots on the photosphere with active regions we can’t see. These are areas of gas thousands of kilometres above the visible surface that are superheated to millions of degrees. Such active regions emit light very strongly in <a href="https://iopscience.iop.org/article/10.3847/1538-4357/ab2e01">ultra-violet and x-ray radiation</a>.</p>
<p>The oldest and easiest way of approximating solar activity at any given time is to simply count the number of sunspots visible on the photosphere. The more sunspots, the more solar activity, and hence the greater overall emission of ultra-violet and x-rays. These emissions are largely absorbed by the Earth’s atmosphere before they reach the ground, causing heating (although some studies suggest the situation is <a href="https://www.nature.com/articles/nature09426">more complicated</a>).</p>
<p>Like our planet, the sun also has a magnetic field that extends outwards. The solar magnetic field defines the size of the solar system and can deflect incoming charged particle radiation from space, called cosmic rays. These cosmic rays have been linked with the <a href="https://www.atmos-chem-phys.net/16/5853/2016/">Earth’s atmospheric chemistry</a>, <a href="https://physicsworld.com/a/physicists-claim-further-evidence-of-link-between-cosmic-rays-and-cloud-formation/">seeding cloud formation</a> and <a href="https://www.sciencemag.org/news/2013/05/do-cosmic-rays-grease-lightning">extreme lightning storms</a>, meaning they affect temperature and weather. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/311601/original/file-20200123-162228-kpakap.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/311601/original/file-20200123-162228-kpakap.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/311601/original/file-20200123-162228-kpakap.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/311601/original/file-20200123-162228-kpakap.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/311601/original/file-20200123-162228-kpakap.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/311601/original/file-20200123-162228-kpakap.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/311601/original/file-20200123-162228-kpakap.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Largest sunspot of the solar cycle, seen on Oct. 18, 2014.</span>
<span class="attribution"><span class="source">NASA</span></span>
</figcaption>
</figure>
<p>The number of sunspots rises and falls as part of a roughly 11-year <a href="https://earthsky.org/space/solar-cycle-24-25-sunspot-predictions">solar activity cycle</a>. There are many sunspots – and more associated emissions of UV and X-rays – at solar maximum and few or even no sunspots at solar minimum.</p>
<p>The solar magnetic field also varies in strength with this solar cycle. It is weakest at solar minimum and strongest at solar maximum. When the solar magnetic field is weak, more cosmic rays can reach the Earth’s atmosphere and <a href="https://iopscience.iop.org/article/10.1088/1748-9326/8/4/045022">affect the climate</a> (as well as the <a href="https://theconversation.com/mars-mission-how-increasing-levels-of-space-radiation-may-halt-human-visitors-94052">radiation environment</a> of space).</p>
<h2>Our current cycle</h2>
<p>Some of the earliest scientific sunspot observations were made by <a href="http://galileo.rice.edu/sci/observations/sunspot_drawings.html">Galileo Galilei in the 1610s</a>. From the 1700s, such observations became more regular. They constitute one of the longest historically continuous data sets in all of science. The first observed solar cycle (1755-1766) is called solar cycle 1, the next solar cycle 2, and so on. The most recent is solar cycle 24, which <a href="https://www.sciencedaily.com/releases/2010/08/100812151647.htm">officially began</a> in December 2008 and is still ongoing. We are rapidly approaching the next solar minimum, which is expected in the next year or so. </p>
<p>Solar cycle 24 is unusually weak, with a relatively low number of sunspots, compared to previous cycles. The last one this weak was solar cycle 14, which began in January 1902. </p>
<p>If solar activity did play a significant role in recent changes in global temperatures, then those temperatures should have stayed roughly the same or even declined over the last decade. A <a href="https://www.sciencedirect.com/science/article/pii/S1364682612000417">paper from 2012</a> even predicted there would be a 1.0°C decrease in temperatures. Clearly this has not turned out to be the case. The hottest decade on record has coincided with the weakest solar cycle for over a century. </p>
<p>Given this combination of factors, it is rather difficult to defend the position that solar activity is indeed responsible for present climate change without a radical shake up of the understanding of solar physics. In the graphs below we have attempted to correlate the number of sunspots with variations in global sea surface temperatures (taken from the <a href="https://www.data.jma.go.jp/gmd/kaiyou/english/long_term_sst_global/glb_warm_e.html">Japan Meteorological Agency</a>), and global surface temperatures (taken from <a href="https://data.giss.nasa.gov/gistemp/">GISTEMP data</a>).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/311630/original/file-20200123-162232-pda5os.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/311630/original/file-20200123-162232-pda5os.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/311630/original/file-20200123-162232-pda5os.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=364&fit=crop&dpr=1 600w, https://images.theconversation.com/files/311630/original/file-20200123-162232-pda5os.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=364&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/311630/original/file-20200123-162232-pda5os.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=364&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/311630/original/file-20200123-162232-pda5os.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=458&fit=crop&dpr=1 754w, https://images.theconversation.com/files/311630/original/file-20200123-162232-pda5os.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=458&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/311630/original/file-20200123-162232-pda5os.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=458&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Graphs showing change in temperature as a function of year or number of sunspots.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The top panels show the warming trend and sunspot number over time. Our analysis reveals no significant correlation between solar activity, based on sunspot number, and atmospheric or sea surface temperatures over the last century. The divergence between sunspot number and temperatures is particularly apparent in the most recent solar cycle. </p>
<p>The lower panels show scatter plots of the number of sunspots against temperature, and again no clear relationship is visible. You can work out mathematically how good the correlation is by measuring how close the datapoints are to a straight line. In such a calculation, a value of 0 suggests the data is random noise and a value of 1 represents a perfect correlation. We got values of between 0.09 and 0.04, which suggests that the variation is largely due to factors other than solar activity. </p>
<p>When looking at global temperatures, the average value serves as a baseline and any observed difference from this is called a temperature anomaly. It is clear from the lower panels that increasing the sunspot number has little discernible effect on the global temperature anomaly. If it did, we would see points clustered around a line sloping upwards to the right in each plot.</p>
<p>These observations of the present solar cycle make it very difficult to defend the position that solar activity is ultimately responsible for the world’s current warming trend. Instead they fit with the argument that human influences are responsible for a large amount of the recent increase in global temperatures.</p>
<p>While the sun is responsible for the overall climactic conditions on Earth, there has not been enough of a long-term difference in solar activity since industrialisation to fully explain our current global warming trend.</p><img src="https://counter.theconversation.com/content/130154/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Solar activity is sometimes blamed for climate change but the data suggests otherwise.Gareth Dorrian, Post Doctoral Research Fellow in Space Science, University of BirminghamIan Whittaker, Lecturer in Physics, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1124152019-06-20T00:16:13Z2019-06-20T00:16:13ZCurious Kids: how is the Sun burning?<figure><img src="https://images.theconversation.com/files/263076/original/file-20190311-86696-1503s74.jpg?ixlib=rb-1.1.0&rect=5%2C0%2C3988%2C2000&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A nuclear reaction is under way inside the Sun. </span> <span class="attribution"><span class="source">Emily Nunell/The Conversation CC-NY-BD</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p><em><a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a> is a series for children. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au You might also like the podcast <a href="http://www.abc.net.au/kidslisten/imagine-this/">Imagine This</a>, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.</em> </p>
<hr>
<blockquote>
<p><strong>If nothing can burn without oxygen then how is the Sun burning? – question from Shashikant Patil.</strong></p>
</blockquote>
<hr>
<p>It’s true that here on Earth, if you want to burn something you need oxygen. But the Sun is different. It is not burning with the same kind of flame you would have on Earth if you burned a candle. </p>
<p>Have you heard of a nuclear reaction? It is a very powerful process that causes a <em>lot</em> of energy to be released. Well, inside the giant ball of gas that we call the Sun, a nuclear reaction is happening right now.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/278225/original/file-20190606-40719-bfti09.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/278225/original/file-20190606-40719-bfti09.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/278225/original/file-20190606-40719-bfti09.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/278225/original/file-20190606-40719-bfti09.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/278225/original/file-20190606-40719-bfti09.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/278225/original/file-20190606-40719-bfti09.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/278225/original/file-20190606-40719-bfti09.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/278225/original/file-20190606-40719-bfti09.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">NASA’s Solar Dynamics Observatory captured this image of a solar flare – as seen in the bright flash on the right side – on Sept. 10, 2017.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/feature/goddard/2017/active-region-on-sun-continues-to-emit-solar-flares">Credits: NASA/SDO/Goddard</a></span>
</figcaption>
</figure>
<p>This means light particles are smashing into each other very, very fast. They hit each other so fast and so hard they sort of glue together. This is what scientists call “fusion” and it can cause other elements and atoms to be created. All this activity causes a lot of energy to be released, which heats up everything near it.</p>
<p>The hottest part of the Sun is its core. The heat and light spreads out from the centre of the ball of gas toward the edges, and that’s what makes the Sun glow.</p>
<p>So there is no normal “flame” in the Sun – at least not like the flames we have in a fire here on Earth – because the energy and light and heat is coming from the nuclear reaction. </p>
<p>And because there’s no normal flame, you don’t need oxygen.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-does-the-world-store-nuclear-waste-and-not-just-shoot-it-into-the-sun-or-deep-space-108675">Curious Kids: why does the world store nuclear waste and not just shoot it into the Sun or deep space?</a>
</strong>
</em>
</p>
<hr>
<h2>Did you know the Sun is also loud?</h2>
<p>All this activity inside the Sun creates a lot of sound waves. So the Sun is loud and vibrates like a church bell. </p>
<p>The high temperatures inside make sound waves travel super fast and smash into each other, and that’s what causes the vibration. Solar quakes shake the Sun very ferociously. These can cause what we call “solar flares”, where a powerful burst of energy shoots out from the Sun.</p>
<p>Here’s a video of a solar flare that happened in 2017:</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ybfAvEVpBMo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">NASA.</span></figcaption>
</figure>
<p>I am an astrophysicist fascinated by the vibrations of the Sun. I am searching to discover more quakes inside the Sun and other stars, too (after all, the Sun is just a star). </p>
<p>If you are interested in finding solar quakes, too, check out the pictures from NASA’s <a href="https://sdo.gsfc.nasa.gov/">Solar Dynamics Observatory</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-is-there-anything-hotter-than-the-sun-105748">Curious Kids: Is there anything hotter than the Sun?</a>
</strong>
</em>
</p>
<hr>
<p><em>Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au</em></p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><em>Please tell us your name, age and which city you live in. We won’t be able to answer every question but we will do our best.</em></p><img src="https://counter.theconversation.com/content/112415/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alina Donea does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It’s true that here on Earth, if you want to burn something you need oxygen. But the Sun is different. It is not burning with the same kind of flame you would have on Earth if you burned a candle.Alina Donea, Senior Lecturer, Monash Centre for Astrophysics, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/508872015-11-23T12:44:16Z2015-11-23T12:44:16ZNew early-warning system could protect Earth from explosive space weather<figure><img src="https://images.theconversation.com/files/102814/original/image-20151123-18230-woh9v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/gsfc/6819077978">NASA Goddard Space Weather Center</a></span></figcaption></figure><p>The sun can erupt with flares more energetic than 30 billion times the yield of all nuclear weapons <a href="https://books.google.co.uk/books?id=xAwAAAAAMBAJ&lpg=PA63&dq=510.3&as_pt=MAGAZINES&pg=PA61#v=onepage&q=510.3&f=false">ever detonated</a>. The energetic particles released by solar flares tunnel a path through our inner solar system with speeds regularly exceeding 6 million kph. If the Earth is unfortunate enough to sweep through the path of these particles, they can cause catastrophic problems by acting like bullets of radiation, damaging electrical and electronic equipment.</p>
<p>Experts have warned that even a single monster solar flare could cause <a href="http://www.inquisitr.com/2550342/white-house-prepares-for-massive-solar-storm-that-could-cause-2-trillion-in-damages/">up to US$2 trillion worth of damage on Earth</a>. This could include the loss of communication and navigation satellites and electricity grids. Dangers to human life and health could follow.</p>
<p>With this in mind, it is no wonder space weather has now been added as one of the greatest dangers to life on Earth in the <a href="https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/419549/20150331_2015-NRR-WA_Final.pdf">UK’s national risk register</a>, only fractionally behind terrorist attacks. It’s paramount that we study the behaviour of the sun so we can create an early-warning system to alert of us impending danger from this kind of space weather.</p>
<h2>Destructive solar flares</h2>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/102818/original/image-20151123-18227-3he8cs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/102818/original/image-20151123-18227-3he8cs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/102818/original/image-20151123-18227-3he8cs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/102818/original/image-20151123-18227-3he8cs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/102818/original/image-20151123-18227-3he8cs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/102818/original/image-20151123-18227-3he8cs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/102818/original/image-20151123-18227-3he8cs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sunspot:Earth ratio.</span>
<span class="attribution"><span class="source">NASA</span></span>
</figcaption>
</figure>
<p>Solar flares’ incredibly destructive power comes from the magnetic fields that are visible across the sun’s entire surface but are most concentrated within regions called sunspots. These spots can be huge, some many times bigger than the Earth, with magnetic field strengths thousands of times more intense than those in the surrounding “quiet” parts of the sun.</p>
<p>As these strong magnetic fields leave the surface of the sun, they extend upwards many thousands of kilometres into the corona, the region of the sun’s atmosphere visible during total solar eclipses. Here they shape the charged particles (plasma) of the corona into giant loop-like structures. The physical strength of the magnetic field lines at the top of these loops is 100 times smaller than similar regions on the solar surface, but the loops still possess immense energy that can twist and shear.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/102828/original/image-20151123-18267-16f8911.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/102828/original/image-20151123-18267-16f8911.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/102828/original/image-20151123-18267-16f8911.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/102828/original/image-20151123-18267-16f8911.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/102828/original/image-20151123-18267-16f8911.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/102828/original/image-20151123-18267-16f8911.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/102828/original/image-20151123-18267-16f8911.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">What a flare up.</span>
<span class="attribution"><span class="source">NASA/SDO</span></span>
</figcaption>
</figure>
<p>Constant buffeting from the underlying atmosphere adds tension to the magnetic field loops, similar to an elastic band being stretched. Scientists believe that when the loops restructure themselves to release this tension they give off a huge blast of electromagnetic energy into space, creating a <a href="http://hesperia.gsfc.nasa.gov/sftheory/flare.htm">solar flare</a>.</p>
<h2>New imaging method</h2>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/102826/original/image-20151123-18255-fujln5.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/102826/original/image-20151123-18255-fujln5.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=841&fit=crop&dpr=1 600w, https://images.theconversation.com/files/102826/original/image-20151123-18255-fujln5.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=841&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/102826/original/image-20151123-18255-fujln5.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=841&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/102826/original/image-20151123-18255-fujln5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1057&fit=crop&dpr=1 754w, https://images.theconversation.com/files/102826/original/image-20151123-18255-fujln5.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1057&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/102826/original/image-20151123-18255-fujln5.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1057&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dunn Solar Telescope.</span>
<span class="attribution"><span class="source">QUB</span></span>
</figcaption>
</figure>
<p>My colleagues and I, working with an international team of researchers, have devised a high-precision way of studying the sun’s atmosphere that is up to ten times faster than previous methods. Using images of all layers of the Sun’s atmosphere taken by specialist telescopes on Earth and in space, we have discovered a wealth of compressible waves similar to sound waves travelling along the magnetic loops. We believe these are caused by vibrations close to the solar surface that are initially trapped within the turbulent layers of <a href="http://soi.stanford.edu/press/ssu8-97/pmodes.html">the sun’s interior</a> before leaking outwards towards the visible surface.</p>
<p>The speed of these waves, which can reach 800,000 kph, depends on the characteristics of the sun’s atmosphere, including its temperature of around 1,000,000°C and the strength of its magnetic field. Studying the wave speed and temperature at different locations in the Sun’s atmosphere at any given time allows us to calculate the magnetic field strength at that point. So by studying how the magnetic field changes on very short timescales, we have the potential to identify the precursors responsible for solar flares and space weather.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/1kSx7AOwEco?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Our new method, <a href="http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys3544.html">which we describe</a> in the journal Nature Physics, can uncover changes in coronal magnetism within around one minute. This is a dramatic improvement on previous direct imaging approaches that often required exposure times exceeding one hour to be able to extract the faint magnetic signals. This means we have a much faster way of examining magnetic field changes in the lead up to solar flares. Ultimately, this could be used to provide advanced warning against such violent space weather.</p>
<p>Our next goal is to fully automate the processes so we can continually monitor the Sun’s coronal magnetic fields in real-time. We hope to use software with artificial intelligence to study the large amount of data this produces and learn why, how, and ultimately when solar flares will erupt. This may not necessarily protect us from the resulting onslaught but it will provide us with crucial advanced warning. This could buy us enough time to minimise the damage associated with 100 billion kilograms of solar “bullets” speeding towards Earth at over 6 million kph.</p><img src="https://counter.theconversation.com/content/50887/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Jess receives funding from the UK's Science and Technology Facilities Council (STFC).</span></em></p>Researchers have found out how to predict solar flares up to ten times faster than previous methods.David Jess, Lecturer and STFC Ernest Rutherford Fellow, Queen's University BelfastLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/450372015-07-24T03:21:33Z2015-07-24T03:21:33ZThe ‘mini ice age’ hoopla is a giant failure of science communication<figure><img src="https://images.theconversation.com/files/89434/original/image-20150723-22836-1h1gjui.jpg?ixlib=rb-1.1.0&rect=0%2C397%2C1024%2C626&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A gigantic sunspot almost 130,000 km across captured by NASA’s Solar Dynamic Observatory on October 23, 2014.</span> <span class="attribution"><a class="source" href="http://www.nasa.gov/content/goddard/largest-sunspot-of-solar-cycle">NASA/SDO</a></span></figcaption></figure><p>This month there’s been a hoopla about a mini ice age, and unfortunately it tells us more about failures of science communication than the climate. Such failures can maintain the illusion of doubt and uncertainty, even when there’s a scientific consensus that the world is warming.</p>
<p>The story starts benignly with a <a href="http://adsabs.harvard.edu/abs/2014ApJ...795...46S">peer-reviewed paper</a> and a presentation in early July by <a href="https://www.northumbria.ac.uk/about-us/our-staff/z/professor-valentina-zharkova/">Professor Valentina Zharkova</a>, from Northumbria University, at Britain’s <a href="http://nam2015.org/">National Astronomy Meeting</a>. </p>
<p>The <a href="http://adsabs.harvard.edu/abs/2014ApJ...795...46S">paper</a> presents a model for the sun’s magnetic field and sunspots, which predicts a 60% fall in sunspot numbers when extrapolated to the 2030s. Crucially, the paper makes no mention of climate.</p>
<p>The first failure of science communication is present in the Royal Astronomical Society <a href="https://www.ras.org.uk/news-and-press/2680-irregular-heartbeat-of-the-sun-driven-by-double-dynamo">press release</a> from July 9. It says that “solar activity will fall by 60 per cent during the 2030s” without clarifying that this “solar activity” refers to a fall in the number of sunspots, not a dramatic fall in the life-sustaining light emitted by the sun.</p>
<p>The press release also omits crucial details. It does say that the drop in sunspots may resemble the <a href="http://www.britannica.com/topic/Maunder-minimum">Maunder minimum</a>, a 17th century lull in solar activity, and includes a link to the <a href="https://en.wikipedia.org/wiki/Maunder_Minimum">Wikipedia article</a> on the subject. The press release also notes that the Maunder minimum coincided with a mini ice age.</p>
<p>But that mini ice age began before the Maunder minimum and may have had multiple causes, <a href="http://blogs.discovermagazine.com/badastronomy/2012/02/01/what-caused-the-little-ice-age/#.VbA8CmSqqko">including volcanism</a>. </p>
<p>Crucially, the press release doesn’t say what the implications of a future Maunder minimum are for climate.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/89408/original/image-20150723-1432-1blzg6q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/89408/original/image-20150723-1432-1blzg6q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/89408/original/image-20150723-1432-1blzg6q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/89408/original/image-20150723-1432-1blzg6q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/89408/original/image-20150723-1432-1blzg6q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/89408/original/image-20150723-1432-1blzg6q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/89408/original/image-20150723-1432-1blzg6q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/89408/original/image-20150723-1432-1blzg6q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A dramatic fall in the number of sunspots won’t lead to a dramatic fall in the light produced by the sun.</span>
<span class="attribution"><span class="source">Credit: NASA/SDO/Goddard Space Flight Center</span></span>
</figcaption>
</figure>
<h2>Filling in the gaps</h2>
<p>How would a new Maunder minimum impact climate? It’s an obvious question, and one that climate scientists have <a href="https://theconversation.com/no-we-arent-heading-into-a-mini-ice-age-44677">already answered</a>. But many journalists didn’t ask the experts, instead drawing their own conclusions. </p>
<p>The UK’s <a href="http://www.telegraph.co.uk/news/science/11733369/Earth-heading-for-mini-ice-age-within-15-years.html">Telegraph</a> warned:</p>
<blockquote>
<p>[…] the earth is 15 years from a mini ice age that will cause bitterly cold winters during which rivers such as the Thames freeze over.</p>
</blockquote>
<p>Pictures of glaciers and frozen rivers loomed large. </p>
<p>News Corp’s <a href="http://blogs.news.com.au/heraldsun/andrewbolt/index.php/heraldsun/comments/cooling_on_the_warming_now_warnings_of_a_mini_ice_age/">Andrew Bolt</a> used the mini ice age to attack climate science. Many climate sceptic bloggers readily accepted the story, despite climate never being mentioned in the <a href="http://adsabs.harvard.edu/abs/2014ApJ...795...46S">peer-reviewed paper</a>.</p>
<p>The media failed in its duty to investigate and inform. It didn’t seek expert comment to put the research into context. Instead journalists tried to answer technical climate science questions themselves, and mostly got it wrong.</p>
<p>As discussed previously, the impact of a new Maunder minimum on climate has been
<a href="http://link.springer.com/article/10.1007%2Fs10712-012-9181-3">studied many times</a>. There’s <a href="http://www1.ncdc.noaa.gov/pub/data/cmb/images/indicators/800k-year-co2-concentration.gif">40% more CO2</a> in the air now than during the 17th century, and global temperature records are <a href="http://www.ncdc.noaa.gov/sotc/global/201506">being smashed</a>. A new Maunder minimum would slow climate change, but <a href="https://theconversation.com/no-we-arent-heading-into-a-mini-ice-age-44677">it is not enough to stop it</a>.</p>
<p>The scientist at the centre of the media storm, Valentina Zharkova, told <a href="http://www.usatoday.com/story/news/nation/2015/07/16/scientists-dispute-ice-age-warnings/30257409/">USA today</a>:</p>
<blockquote>
<p>In the press release, we didn’t say anything about climate change. My guess is when they heard about Maunder minimum, they used Wikipedia or something to find out more about it.</p>
</blockquote>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/89409/original/image-20150723-1435-1t53fqo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/89409/original/image-20150723-1435-1t53fqo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/89409/original/image-20150723-1435-1t53fqo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/89409/original/image-20150723-1435-1t53fqo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/89409/original/image-20150723-1435-1t53fqo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/89409/original/image-20150723-1435-1t53fqo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/89409/original/image-20150723-1435-1t53fqo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Don’t put your ice skates on just yet. Even a new Maunder minimum won’t reverse climate change.</span>
<span class="attribution"><span class="source">CSIRO</span></span>
</figcaption>
</figure>
<h2>Mixed messages</h2>
<p>While Zharkova was surprised by the media coverage, she and <a href="http://www.eurekalert.org/pub_releases/2015-07/lmsu-nia071615.php">others</a> continued to discuss a new mini ice age. </p>
<p>If a mini ice age is at odds with the prior literature, why does Zharkova continue speculating about it? In personal correspondence with Zharkova, she told me it was only after the media coverage that her research was connected to climate change and the Maunder minimum. However, she said that once the connection was made, it did make sense to her.</p>
<p>Zharkova also told <a href="http://www.iflscience.com/environment/mini-ice-age-not-reason-ignore-global-warming">IFLS</a>:</p>
<blockquote>
<p>We didn’t mention anything about the weather change, but I would have to agree that possibly you can expect it [a mini ice age]. </p>
</blockquote>
<p>So it seems Zharkova’s justification is based on media extrapolation of her own press release and Wikipedia, not the extensive peer-reviewed literature on the Maunder minimum itself. </p>
<p>I emailed Zharkova and she sent me two studies that support her views, but they aren’t representative of the literature and I don’t believe she has critically evaluated their content.</p>
<p>Is there any quantitative basis for claims of a mini ice age? Zharkova and her colleagues have cited a <a href="http://www.annualreviews.org/doi/pdf/10.1146/annurev.astro.35.1.33">1997 article</a> by Judith Lean, who showed the sun’s brightness (quantified by solar irradiance) was 3 W per m<sup>2</sup> less during the Maunder minimum than today. More recent studies, including those by Lean, find the solar irradiance varies less than was thought in 1997. </p>
<p>In plain English, the small change in sunlight reaching the Earth during a new Maunder minimum wouldn’t be enough to reverse climate change. For the technically minded, even a 3 W per m<sup>2</sup> change in irradiance corresponds to a radiative forcing of just 0.5 W per m<sup>2</sup> (because the Earth is a sphere and not a flat circle), which is less than the radiative forcing produced by anthropogenic greenhouse gases. </p>
<p>To be blunt: no mini ice age for us. The real story of the impending mini ice age isn’t about climate at all. It is a cautionary tale, of how science should and shouldn’t be communicated.</p>
<p>The lessons to be learned from this is scientists must communicate their science concisely and accurately, especially if we are to avoid the <a href="http://www.abc.net.au/mediawatch/transcripts/s4277443.htm">media frenzy</a> highlighted by the ABC’s Media Watch. If scientists, science organisations and media aren’t careful, they can inadvertently end up promoting dangerous misinformation.</p><img src="https://counter.theconversation.com/content/45037/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael J. I. Brown receives research funding from the Australian Research Council and Monash University, and has developed space-related titles for Monash University's MWorld educational app.
</span></em></p>The recent claim that we might enter a mini ice age in 15 years is not only bad science, but it represents a failure of communication by both scientists and journalists.Michael J. I. Brown, Associate professor, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/446772015-07-14T16:10:02Z2015-07-14T16:10:02ZNo, we aren’t heading into a ‘mini ice age’<figure><img src="https://images.theconversation.com/files/88353/original/image-20150714-21738-dcq5ju.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">London's 'frost fairs' are a thing of the past – not the future.</span> <span class="attribution"><a class="source" href="http://www.bbc.co.uk/news/magazine-25862141">Museum of London</a></span></figcaption></figure><p>Wouldn’t it be great if scientists could make their minds up? One minute they’re telling us our planet is warming up due to human activity and we run the risk of potentially devastating environmental change. Next, they’re <a href="http://www.telegraph.co.uk/news/science/11733369/Earth-heading-for-mini-ice-age-within-15-years.html">warning that the Earth is heading for a mini ice age</a> in the next 15 years.</p>
<p>The latter headline has its roots in a recent <a href="http://nam2015.org/index.php/press-releases/64-irregular-heartbeat-of-the-sun-driven-by-double-dynamo">press release</a> from the UK’s <a href="http://nam2015.org">National Astronomy Meeting</a> that reported on a study suggesting the sun is heading towards a period of very low output. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=698&fit=crop&dpr=1 600w, https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=698&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=698&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=877&fit=crop&dpr=1 754w, https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=877&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=877&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Daily Telegraph was first to run the story.</span>
<span class="attribution"><a class="source" href="http://www.telegraph.co.uk/news/science/11733369/Earth-heading-for-mini-ice-age-within-15-years.html">Telegraph</a></span>
</figcaption>
</figure>
<p>Fluctuations in solar activity are not a new discovery. The <a href="http://www.livescience.com/33345-solar-cycle-sun-activity.html">11-year variation</a> in the number of dark sunspots on the solar surface was discovered more than 150 years ago. We now understand that these spots are symptoms of increased magnetic activity and occur during periods when explosive outbursts of energy and material such as <a href="http://www.nasa.gov/content/goddard/the-difference-between-flares-and-cmes">solar flares and coronal mass ejections</a> are more frequent.</p>
<p>The scientists behind the new research have modelled the rhythmic variations in solar activity over recent decades and predict that a deep low is due between 2030 and 2040. Specifically, the press release suggests that this dip in activity could mark a return to quiet solar conditions not seen for more than 350 years.</p>
<p>How is this astronomy story related to an impending ice age? The period of low solar activity in the 17th century, known as the <a href="https://en.wikipedia.org/wiki/Maunder_Minimum">Maunder minimum</a>, lasted about 70 years and roughly coincided with the “Little Ice Age”, a era characterised by an abnormally high number of harsh winters across the UK and Europe. As almost all <a href="http://www.independent.co.uk/environment/climate-change/mini-ice-age-coming-in-next-fifteen-years-new-model-of-the-suns-cycle-shows-10382400.html">newspaper stories</a> have reported, during several particularly cold winters the Thames froze, enabling <a href="http://www.bbc.co.uk/news/magazine-25862141">frost fairs</a> to be held on the ice.</p>
<p>Given the apparently strong link between low solar activity and the Little Ice Age reported in the press, it’s understandable that the prospect of a return to Maunder minimum conditions has stimulated a lot of interest. </p>
<h2>Should we be worried?</h2>
<p>If this link between variations in solar activity and changes in the Earth’s climate seems obvious, that’s because it is. When the amount of energy emitted by the sun changes, it has an affect on our climate. </p>
<p>But the real issue is just how strong this influence is compared to other factors. The total <a href="http://science.jrank.org/pages/6875/Total-Solar-Irradiance.html">solar irradiance</a>, a measure of the power produced by the sun in the form of electromagnetic radiation, varies by only about 0.1% over the course of the 11-year solar cycle. Climate scientists have understood this effect for some time and it is <a href="http://www.washingtonpost.com/news/energy-environment/wp/2015/02/23/no-the-sun-isnt-driving-global-warming/">already</a> built into the computer models that are used to try and forecast our climate.</p>
<p>But there are still some uncertainties. Changes in the ultraviolet portion of the Sun’s output over a solar cycle can be much greater and can deposit energy in the stratosphere – at altitudes above 10km. How this energy influences our weather and climate in the lower atmosphere is still not clear, but there is growing <a href="http://link.springer.com/article/10.1007%2Fs10712-012-9181-3">evidence</a> that during periods of low solar activity, atmospheric “blocking” events are more prevalent. These blocking episodes comprise extensive and almost stationary anti-cyclones in the eastern Atlantic that can last for several weeks, hindering the flow of the jet stream and leading to colder winters in the UK and Europe.</p>
<p>The good news is that if the sun is heading towards Maunder minimum conditions, the likelihood of which varies greatly in different studies, then a new ice age is not inevitable. During the Little Ice Age, the atmospheric blocking effect probably played a role, but so did <a href="http://www.sciencedaily.com/releases/2012/01/120130131509.htm">increased global volcanic activity</a> that ejected gas and ash in the atmosphere, reflecting solar radiation back into space. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=255&fit=crop&dpr=1 600w, https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=255&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=255&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=320&fit=crop&dpr=1 754w, https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=320&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=320&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Little Ice Age began before the Maunder minimum.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Sunspot_Numbers.png">Hoyt & Schatten / wiki</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>So we have to be careful associating the Maunder minimum with the Little Ice Age. A look at the data shows that the Little Ice Age began a long time (certainly more than a century) before the start of the Maunder minimum – and continued long after it ended. In any case, the Little Ice Age wasn’t really an ice age. Although cold winters in Europe were unusually common, it doesn’t seem to have been a global phenomenon. <a href="http://download.springer.com/static/pdf/590/art%3A10.1007%2Fs10712-012-9181-3.pdf?originUrl=http%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2Fs10712-012-9181-3&token2=exp=1436832094%7Eacl=%2Fstatic%2Fpdf%2F590%2Fart%3A10.1007%2Fs10712-012-9181-3.pdf%3ForiginUrl%3Dhttp%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2Fs10712-012-9181-3*%7Ehmac=a114ec160a0d978e4807c4934ffd2942ab3f184103b2bda8e814968366bcea7e">Research</a> suggests it was a regional phenomenon and that the colder winters in Europe would have been accompanied by warmer ones elsewhere.</p>
<p>So what about global climate change? If solar activity is falling, and that has a cooling influence over the UK and Europe, isn’t that a good thing?</p>
<p>Unfortunately not. The overwhelming consensus among the world’s climate scientists is that the influence of solar variability on the climate is dwarfed by the impact of increased levels of carbon dioxide in the atmosphere. Most <a href="http://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/aug/14/global-warming-solar-minimum-barely-dent">calculations</a> suggest that a new “grand solar minimum” in activity would have a cooling effect that would temporarily offset just a few year’s worth of the warming due to the emission of carbon dioxide by humans.</p>
<p>We may well be heading towards a period of low solar activity, but a new mini ice age seems very unlikely at this point.</p><img src="https://counter.theconversation.com/content/44677/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jim Wild receives funding from the Science and Technology Facilities Council and the Natural Environment Research Council. He is also the vice-President (Geophysics) of the Royal Astronomical Society, but is writing here as an independent academic scientist. He occasionally works with a variety of UK-based travel and tourism companies to engage relevant audiences on topics related to his research.
</span></em></p>Any drop in solar activity will be dwarfed by the impact of increased carbon dioxide in the atmosphere.Jim Wild, Professor of Space Physics, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/340022014-11-11T19:29:36Z2014-11-11T19:29:36ZGiant sunspot returns – and it’s bigger and badder than ever<figure><img src="https://images.theconversation.com/files/64107/original/gsz4d9ct-1415599731.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ten Earths could be laid across the diameter of the gigantic sunspot in AR2191 during its previous rotation – captured on October 23, 2014.</span> <span class="attribution"><a class="source" href="http://www.nasa.gov/content/goddard/largest-sunspot-of-solar-cycle/#.VGBWKVOUcWd">NASA’s Solar Dynamic Observatory </a></span></figcaption></figure><p>The largest sunspot seen in 24 years is rotating back to face the Earth, and it looks to have grown even bigger.</p>
<p>Last month, the solar active region known as AR12192 (also known as AR2192 to some of its friends) <a href="http://www.iflscience.com/space/jupiter-sized-sunspot-largest-24-years">entertained the world</a> with the sunspot clearly visible with the naked eye (with some appropriate and approved solar-watch or eclipse dark glasses, of course), and produced a series of large flares.</p>
<p>But after spending some time over on the far side of the sun, it hasn’t finished impressing us yet.</p>
<p>AR12192 is due to rotate back onto our side of the sun today (November 12) and and it has grown. Because of its size, the leading edge would actually have appeared about a day earlier.</p>
<p>Charles Lindsey, of North West Research Associates (NWRA) in Boulder Colorado (and a frequent visitor to Monash University in Australia), has been following the progress of AR12192 since it disappeared around the west limb of the sun a couple of weeks ago, and found that it has grown significantly. </p>
<p>The sun rotates about once every 27 days as viewed from the Earth, so we haven’t been able to see AR12192 directly since then. But using the helioseismology technique <a href="https://www.cora.nwra.com/%7Edbraun/reprints/lb00.pdf">acoustic holography</a> that Dr Lindsey and his colleague Doug Braun developed, they can “see” large active regions on the far side by <a href="https://www.cora.nwra.com/%7Edbraun/reprints/fsi_science.pdf">computationally regressing oscillations</a> (waves) observed on the nearside back to their sources.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/64110/original/tpq5vwrn-1415600752.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64110/original/tpq5vwrn-1415600752.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=233&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64110/original/tpq5vwrn-1415600752.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=233&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64110/original/tpq5vwrn-1415600752.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=233&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64110/original/tpq5vwrn-1415600752.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=293&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64110/original/tpq5vwrn-1415600752.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=293&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64110/original/tpq5vwrn-1415600752.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=293&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Far side image of AR12192 in the yellow tinted section which we only ‘see’ using helioseismology.</span>
<span class="attribution"><a class="source" href="http://jsoc.stanford.edu/data/farside/">Stanford University’s Joint Science Operations Center</a></span>
</figcaption>
</figure>
<p>Drs Lindsey and Braun’s far side imaging technique is now routinely used to keep an eye on active regions popping up or developing on the other side of the sun. The image (above) shows a seismic reconstruction of the far side (in yellow) with a very clear and very large active region in the southern hemisphere. This is AR12192.</p>
<h2>Why all the activity?</h2>
<p>So, what is an active region, and how does it relate to sunspots? Active regions are huge agglomerations of magnetic field that bubble up to the surface from deep in the sun’s interior.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/yXYrLJCA9DQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Sunspots are the areas of strongest field, up to about 3,000 Gauss. To put that in context, the Earth’s magnetic field is around half a Gauss.</p>
<p>The magnetic field largely inhibits the boiling convection normally seen across the solar surface. Convection is the mechanism that carries most of the energy from the nuclear furnace in the core through the outer 29% of the sun.</p>
<p>That is why sunspots appear dark; magnetism halts the conveyor belt.</p>
<p>The sun is currently near the maximum of Solar Cycle 24 – the 24th cycle of solar activity since detailed recording began in 1755. Sunspot number rises and falls on a roughly 11-year cycle, and although Cycle 24 is very weak compared to others in the last century, it can still produce a doozy of a spot. </p>
<p>But active regions don’t just give us sunspots. They also produce flares, the most energetic events in the solar system.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64111/original/3c2k9rct-1415601587.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64111/original/3c2k9rct-1415601587.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64111/original/3c2k9rct-1415601587.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=436&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64111/original/3c2k9rct-1415601587.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=436&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64111/original/3c2k9rct-1415601587.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=436&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64111/original/3c2k9rct-1415601587.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=548&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64111/original/3c2k9rct-1415601587.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=548&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64111/original/3c2k9rct-1415601587.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=548&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The bright light in the centre of the image shows an X-class solar flare on October 26, 2014. This was the third X-class flare in 48 hours.</span>
<span class="attribution"><a class="source" href="http://www.nasa.gov/content/goddard/sunspot-ar2192-release-x2.0-class-solar-flare-on-oct-26-2014/#.VGBdpVOUcWd">NASA’s Solar Dynamic Observatory</a></span>
</figcaption>
</figure>
<p>Flares occur when the complex magnetic field twists and stretches to such an extent that it snaps, like a rubber band breaking, and then reconnects to other field lines.</p>
<p>This releases huge bursts of energy over several minutes, up to 6×10<sup>25</sup> Joules for the largest X-class flares. This is about 100,000 times the total energy usage of humans in a full year.</p>
<p>Coronal mass ejections (<a href="http://solarscience.msfc.nasa.gov/CMEs.shtml">CMEs</a>) also commonly emerge from active regions. These are massive bubbles of gas, weighing as much as 100 billion kg, that burst into space at up to 1,000 km per second, carrying huge loads of charged particles and magnetic flux.</p>
<p>CMEs are often – though not always – associated with flares, and flares may or may not have accompanying CMEs. A flare that doesn’t is termed “ordinary”.</p>
<p>On its first pass, the huge AR12192 was comparable in size to Jupiter and produced several (ordinary) <a href="http://www.nasa.gov/mission_pages/sunearth/news/X-class-flares.html#.VGFCDFOUcWc">X-class flares</a> and many smaller ones, but no large CMEs.</p>
<p>But Hugh Hudson of Space Sciences Laboratory at Berkeley, California, notes that older active regions tend to produce more CMEs, so he is expecting a big CME show this time around.</p>
<h2>Impact on Earth</h2>
<p>But what does this mean for us on Earth? CMEs in particular can have a massive impact on the Earth’s magnetosphere, causing stunning aurorae, power blackouts, interruptions to telecommunications and damage to satellites in orbit.</p>
<p>The so-called Carrington flare of 1859 produced aurorae visible in Queensland, and damaged telegraph stations around the world. Our modern technological world is far more vulnerable.</p>
<p>So, if AR12192 launches any large CMEs in our direction when it comes around to our side, we’d better batten down the hatches.</p>
<p>That can mean disconnecting long-distance power grids, placing satellites in safe mode and rerouting aircraft on polar routes.</p><img src="https://counter.theconversation.com/content/34002/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Cally has previously received funding from the Australian Research Council.</span></em></p>The largest sunspot seen in 24 years is rotating back to face the Earth, and it looks to have grown even bigger. Last month, the solar active region known as AR12192 (also known as AR2192 to some of its…Paul Cally, Professor of Solar Physics, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/286122014-07-06T20:11:30Z2014-07-06T20:11:30ZThe Southern Lights put on a display in the night sky<figure><img src="https://images.theconversation.com/files/53132/original/yy26bxnp-1404703615.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Amazing colours in the Southern Lights seen from Primrose Sands, near Hobart. </span> <span class="attribution"><a class="source" href="http://www.photography.ffourie.com/Gallaries/Most-Recent/i-G4ZLd8K/A">Francois Fourie</a></span></figcaption></figure><p>Over the past few months night sky watchers in the southern parts of Australia have been presented with lots of beautiful displays of the Aurora Australis or Southern Lights.</p>
<p>So what causes the impressive display of lights in the night sky?</p>
<p>As with any scientific question, the easy questions often don’t have easy answers. First we need to know a little bit about the sun and its behaviour.</p>
<p>The sun is not a constant bright object in the sky. It’s true that its brightness doesn’t change much in the visible range (a fraction of a percent over its cycle) but it is much more variable in the ultraviolet (UV) and x-ray range.</p>
<p>In fact x-rays from the sun go from virtually none to frequent events, and back to none, over a cycle known as the solar cycle.</p>
<p>This cycle lasts on average a little more than 11 years but can be a year and a bit longer or shorter from one cycle to the next.</p>
<h2>The sunspot cycle</h2>
<p>The most obvious sign of the solar cycle is the number of sunspots that appear, hence the cycle is often called the <a href="http://solarscience.msfc.nasa.gov/SunspotCycle.shtml">solar sunspot cycle</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/52827/original/r8dppxqs-1404267427.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/52827/original/r8dppxqs-1404267427.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/52827/original/r8dppxqs-1404267427.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=456&fit=crop&dpr=1 600w, https://images.theconversation.com/files/52827/original/r8dppxqs-1404267427.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=456&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/52827/original/r8dppxqs-1404267427.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=456&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/52827/original/r8dppxqs-1404267427.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=573&fit=crop&dpr=1 754w, https://images.theconversation.com/files/52827/original/r8dppxqs-1404267427.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=573&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/52827/original/r8dppxqs-1404267427.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=573&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The solar cycle captured over a 10-year period.</span>
<span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2014/03/Solar_cycle">SOHO (ESA & NASA)</a></span>
</figcaption>
</figure>
<p>At solar minimum there are very few if any dark spots, and at solar maximum there are lots. The cycle repeats every 11-odd years, with the sun’s magnetic field reversed in alternate cycles. </p>
<p>Sunspots are easy to observe. Put a tiny pinhole in a large dark piece of card or paper and let the sun shine through this pinhole onto a white sheet and you will see a projected image of the sun on the white sheet. You can also see the larger sunspots.</p>
<p>It works best if you have dark surroundings, like using a sliver of sunlight through the crack in curtains as the source.</p>
<p>This technique is what Chinese astrologers used around 1000AD to see the sunspots. They discovered the 11-year cycle - though they were really trying to foretell events!</p>
<p>Sunspots were rediscovered in the 1600s following the invention of the telescope but it is clear from the Chinese records that the cycle has been around for a long time.</p>
<h2>Carried on the solar winds</h2>
<p>The sunspots are only one manifestation of how the sun changes during its cycle. Another change is the number of eruptions that occur on the sun (related to the sunspots) and the strength and gustiness of the solar wind.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/52844/original/nx4cdpvk-1404271820.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/52844/original/nx4cdpvk-1404271820.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/52844/original/nx4cdpvk-1404271820.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/52844/original/nx4cdpvk-1404271820.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/52844/original/nx4cdpvk-1404271820.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/52844/original/nx4cdpvk-1404271820.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/52844/original/nx4cdpvk-1404271820.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/52844/original/nx4cdpvk-1404271820.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Aurora Australis as seen from Hobart’s Mt Wellington.</span>
<span class="attribution"><a class="source" href="http://www.lukeobrien.com.au/aurora-australis-timelapse-mt-wellington">Luke O Brien</a></span>
</figcaption>
</figure>
<p>The <a href="http://solarscience.msfc.nasa.gov/SolarWind.shtml">solar wind</a> is a constant stream of gas that is so hot that the electrons have been stripped away from the atoms so the gas is charged (known as a plasma).</p>
<p>This gas travels fast from the sun and constantly hits the earth’s magnetic field and is then deflected around the earth. Typically the wind travels at about 400 kilometres per second but during eruptive events the wind speed can reach up to several thousand kilometres per second.</p>
<p>At solar minimum times there is enough wind for some of the plasma to compress the earth’s magnetic field. This in turn speeds up electrons already in the field, which then travel along the field into polar regions, impact with atmospheric atoms and give them a little energy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/52845/original/vtt9rkxc-1404272131.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/52845/original/vtt9rkxc-1404272131.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/52845/original/vtt9rkxc-1404272131.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=278&fit=crop&dpr=1 600w, https://images.theconversation.com/files/52845/original/vtt9rkxc-1404272131.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=278&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/52845/original/vtt9rkxc-1404272131.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=278&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/52845/original/vtt9rkxc-1404272131.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=349&fit=crop&dpr=1 754w, https://images.theconversation.com/files/52845/original/vtt9rkxc-1404272131.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=349&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/52845/original/vtt9rkxc-1404272131.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=349&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The lights captured in the trees from Seven Mile Beach, near Hobart’s airport.</span>
<span class="attribution"><a class="source" href="http://www.photography.ffourie.com/Gallaries/Most-Recent/i-nW44pnk">Francois Fourie</a></span>
</figcaption>
</figure>
<p>The energised atmospheric atoms then release this excess energy as light – red high up due to energised oxygen atoms, green lower down due to a slightly different energisation of oxygen atoms, and violet (which is hard to see) due to nitrogen.</p>
<p>All this happens a few hundred kilometres up in the atmosphere, well above the cloud layers.</p>
<h2>An active sun</h2>
<p>When the sun is more active and the eruptive events give rise to very fast winds, the buffeting of the earth’s magnetic field is so strong and it distorts so much that the part where the lines come down to the ground, usually only near the poles, expands toward the equator. That is when the aurorae are seen further from the poles.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/52846/original/n6k7cby6-1404272211.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/52846/original/n6k7cby6-1404272211.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/52846/original/n6k7cby6-1404272211.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/52846/original/n6k7cby6-1404272211.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/52846/original/n6k7cby6-1404272211.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/52846/original/n6k7cby6-1404272211.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/52846/original/n6k7cby6-1404272211.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/52846/original/n6k7cby6-1404272211.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Aurora Australis seen over Tasmania’s South Arm, south of Hobart.</span>
<span class="attribution"><a class="source" href="http://www.lukeobrien.com.au/southern-lights-tasmania-2014-south-arm-april-21">Luke O Brien</a></span>
</figcaption>
</figure>
<p>The sun is currently passing through its maximum state and so there are more occasions when conditions are right for seeing the aurorae from southern Australia.</p>
<p>You need to get clear of city lights and have a good view to the south. The best time to see them is an hour or two either side of midnight.</p>
<p>With especially strong “solar storms”, as they are called, the aurorae can be seen earlier or later in the night and higher in the sky, not just low on the horizon.</p>
<p>A whole range of other phenomena associated with these storms are collectively known as “<a href="http://soho.nascom.nasa.gov/spaceweather/">Space Weather</a>”. These have less benign impacts on us and our technology but that is a story for another time.</p>
<hr>
<p><em>You can see more images of the Aurora Australis (or Southern Lights) at a photographic exhibition at the Kingston Beach Arts Hub Gallery, Kingston Beach Community Hall, 20 Beach Road, Kingston Beach, Tasmania, open until August 7, 2014.</em></p><img src="https://counter.theconversation.com/content/28612/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Marc Duldig does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Over the past few months night sky watchers in the southern parts of Australia have been presented with lots of beautiful displays of the Aurora Australis or Southern Lights. So what causes the impressive…Marc Duldig, Adjunct Researcher, University of TasmaniaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/221552014-01-21T19:02:31Z2014-01-21T19:02:31ZWhy is the sun going quiet?<figure><img src="https://images.theconversation.com/files/39534/original/4g9hwq5j-1390281080.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">What's going on up there?</span> <span class="attribution"><span class="source">VinothChandar</span></span></figcaption></figure><p>The sun is our nearest <a href="https://theconversation.com/explainer-what-are-stars-15235">star</a> and the source of all our light and heat on Earth but recent <a href="http://www.bbc.co.uk/news/science-environment-25743806">reports</a> have highlighted an ongoing steep decline in solar activity.</p>
<p>This story is a reminder that our sun is a variable star whose dynamic production of magnetism, activity and winds have implications for our planet.</p>
<p>Solar magnetic fields power solar activity, including sunspots, explosive events known as solar flares and coronal mass ejections, and an outward-flowing solar wind.</p>
<p>The sun’s activity and wind bathes Earth in a changing space environment of high-energy radiation and fast-moving particles called “<a href="http://www.ips.gov.au">space weather</a>”. This gives us both the beauty of the aurorae and disruptive effects on <a href="http://www.nasa.gov/topics/solarsystem/features/spaceweather_hazard.html">communications and other technology</a>.</p>
<p>Solar activity varies over time, with the 11-year sunspot cycle being the most familiar example. Solar activity also varies more widely over longer timescales, producing “<a href="http://solarphysics.livingreviews.org/open?pubNo=lrsp-2008-3&amp;page=articlesu16.html">grand maxima</a>” and “grand minima”.</p>
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<a href="https://images.theconversation.com/files/39528/original/hx5jbwpy-1390280570.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/39528/original/hx5jbwpy-1390280570.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/39528/original/hx5jbwpy-1390280570.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=276&fit=crop&dpr=1 600w, https://images.theconversation.com/files/39528/original/hx5jbwpy-1390280570.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=276&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/39528/original/hx5jbwpy-1390280570.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=276&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/39528/original/hx5jbwpy-1390280570.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=347&fit=crop&dpr=1 754w, https://images.theconversation.com/files/39528/original/hx5jbwpy-1390280570.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=347&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/39528/original/hx5jbwpy-1390280570.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=347&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="attribution"><span class="source">NASA</span></span>
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<p>The most famous of these is the <a href="http://www.britannica.com/EBchecked/topic/369980/Maunder-minimum">Maunder minimum</a> in sunspot activity from around <a href="http://solarscience.msfc.nasa.gov/SunspotCycle.shtml">1645 to 1715</a>.</p>
<p>The current rate and extent at which solar activity is falling has been interpreted as the beginning of <a href="http://www.newscientist.com/article/dn24512-solar-activity-heads-for-lowest-low-in-four-centuries.html#.Ut3uUP3n3K0">another grand minimum</a>, and raises the issue of what it means for Earth’s climate.</p>
<p>Variations in solar activity have long been linked to climate variability on Earth, with the most familiar historical example being the Maunder minimum. This corresponded to relatively cold climatic conditions described as the “<a href="http://solarscience.msfc.nasa.gov/SunspotCycle.shtml">Little Ice Age</a>” when rivers that were normally ice-free froze and snow fields remained year-round at lower altitudes.</p>
<p>Question of how solar activity influences the Earth’s climate remains the subject of <a href="http://www2.mps.mpg.de/projects/sun-climate/sunearth.html">ongoing research</a>. What is becoming clearer is that variations in <a href="http://www.annualreviews.org/doi/abs/10.1146/annurev-astro-082812-141007">solar ultraviolet</a> radiation resulting from solar activity can provide a physical mechanism for the Sun to influence the Earth’s atmosphere.</p>
<p>However, it is important to understand that research also indicates that these solar effects are <a href="http://www.mpg.de/496690/pressRelease20040802">minor</a> compared to modern-day <a href="http://www.climatechange2013.org/images/uploads/WGI_AR5_SPM_brochure.pdf">anthropogenic effects</a>. Even if there is measurable cooling, a grand minimum should not be relied upon to slow <a href="http://www.abc.net.au/science/articles/2010/03/11/2843111.htm">global warming</a>.</p>
<p>Climatic effects aside, a grand minimum in solar activity would mean reduced auroral displays, and some lessening of the hazards caused by space weather for spacecraft, and any occupants.</p>
<h2>Why the fluctuations?</h2>
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<a href="https://images.theconversation.com/files/39529/original/7mc857gg-1390280571.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/39529/original/7mc857gg-1390280571.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/39529/original/7mc857gg-1390280571.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=510&fit=crop&dpr=1 600w, https://images.theconversation.com/files/39529/original/7mc857gg-1390280571.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=510&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/39529/original/7mc857gg-1390280571.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=510&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/39529/original/7mc857gg-1390280571.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=641&fit=crop&dpr=1 754w, https://images.theconversation.com/files/39529/original/7mc857gg-1390280571.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=641&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/39529/original/7mc857gg-1390280571.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=641&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The convoluted magnetic field lines extending from the sun.</span>
<span class="attribution"><span class="source">NASA</span></span>
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</figure>
<p>The answer lies in how the sun generates its magnetic field.</p>
<p>As a typical star our sun is a ball of hot gas, more than a hundred times the diameter and hundreds of thousands of times more massive than the Earth. </p>
<p>Inside the sun, the effects of heat, pressure and motion produce electrical currents that in turn generate magnetic fields. This <a href="http://solarscience.msfc.nasa.gov/dynamo.shtml">solar dynamo</a> results in magnetic fields emerging from the sun’s visible surface to power its activity and winds and the space weather experienced by Earth.</p>
<p>Explaining the variable nature of solar activity comes down to understanding the physics of the solar dynamo. At present there is a general <a href="http://solarphysics.livingreviews.org/open?pubNo=lrsp-2008-3&amp;page=articlesu15.html">theoretical picture</a> of how the dynamo can produce magnetic fields and even cycles.</p>
<p>What is less certain is how the dynamo changes into the special state that corresponds to grand minimum, and whether such occurrences are to some extent predictable or purely random.</p>
<p>One way to learn more about the sun and its dynamo is to study other stars. Dynamos occur in many other stars, so observations of stars of different ages can offer clues regarding the past and future of solar magnetism and its effects. These <a href="http://bcool.ast.obs-mip.fr">magnetic studies</a> of stars and their activity and winds can be used to better test the predictions of dynamo theory.</p>
<p>An improved understanding of stellar dynamos may then help us know more about what is happening to the sun today, and perhaps provide a useful tool to forecast future changes in our variable sun.</p><img src="https://counter.theconversation.com/content/22155/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brad Carter is a member of the Bcool project studying stellar magnetic activity.</span></em></p>The sun is our nearest star and the source of all our light and heat on Earth but recent reports have highlighted an ongoing steep decline in solar activity. This story is a reminder that our sun is a…Brad Carter, Associate Professor (Physics), University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.