When Astronomy Gets Closer to Home: Why space weather outreach is important and how to give it impact

When the public think about natural hazards, space weather is not the first thing to come to mind. Yet, though uncommon, extreme space weather events can have an economic impact similar to that of large floods or earthquakes. Although there have been efforts across various sectors of society to communicate this topic, many people are still quite confused about it, having only a limited understanding of the relevance of space weather in their daily lives. As such, it is crucial to properly communicate this topic to a variety of audiences. This article explores why we should communicate space weather research, how it can be framed for different audiences and how researchers, science communicators, policy makers and the public can raise awareness of the topic.


As you sit reading this article, the Sun is brimming with activity. The yellow disc in the sky may appear unimpressive but when looking in the extreme ultraviolet region of the spectrum, the Sun’s hot active regions glow bright (Figure 1). These are areas with an especially strong magnetic field — manifested in the form of dark patches or sunspots on the solar surface — that can be the source of explosive bursts of energy and solar material. Even though the Sun is some 150 million kilometres away, these solar storms can alter the near-Earth space environment, changing our space weather.

Of the solar storms that can hit the Earth, the most damaging are coronal mass ejections. These high-speed bursts of solar material — if powerful enough and directed towards our planet with the proper orientation of their magnetic field — can disturb the Earth’s magnetic field, creating a geomagnetic storm. This can impact power grids and pipelines, and affect communications and transportation systems. Coronal mass ejections and other solar storms such as solar flares — outbursts of radiation and high-energy particles — can also affect spacecraft and satellites and even be a radiation hazard for astronauts and air crews flying at high latitudes and altitudes.

Figure 1. The Sun in the extreme ultraviolet, imaged by NASA’s Solar Dynamics Observatory on 04 December 2014. This wavelength highlights the outer atmosphere of the Sun (corona) and active solar regions, which appear bright in the image. Solar flares and coronal mass ejections would also be highlighted in this channel.
Figure 1. The Sun in the extreme ultraviolet, imaged by NASA’s Solar Dynamics Observatory on 04 December 2014. This wavelength highlights the outer atmosphere of the Sun (corona) and active solar regions, which appear bright in the image. Solar flares and coronal mass ejections would also be highlighted in this channel. (Credit: Image courtesy of NASA/SDO and the AIA, EVE, and HMI science teams)

The importance of communicating space weather research

Space weather may be a concept unfamiliar to many, but, as with any natural hazard, it is important that the public know about it and understand the potential dangers. At its most extreme space weather can cause large-scale power blackouts and, thus, affect global supply chains including food and water supplies, damaging livelihoods and the economy in the process. Severe space weather occurs about once a century on average (Riley, 2012), but milder events can disrupt human activity once or twice per decade (POST Note, 2010). At a time when we are over-reliant on technology and our power grids are more connected than ever, meaning they are more vulnerable to space weather, telling people about this natural hazard becomes all the more crucial.

Space weather is an area of astronomy much closer to home than most, which can in itself act as a hook for audiences, whether children or policy makers. After all, most people have either seen or heard about the most visible and stunning space weather-related phenomenon, the aurora, which forms when particles from the Sun energise the atoms in the Earth’s atmosphere making it glow (Figures 2 and 3).

Communicating space weather is an opportunity to get others interested in space and science, and to inspire younger people to pursue a career in these areas. In more general terms researchers of space weather, as is the case with many areas of astronomy, have much to gain from communicating their research. Communicating space weather as a researcher can help to improve a CV, hone presentation and writing skills and bring a new perspective to research. Expanding the audience for this research beyond the astronomy community can further lead to interdisciplinary collaborations and an increase in citations for relevant research papers.

In addition, communicating space weather research with the public is a way of justifying the taxpayers’ money that funds most solar–terrestrial research. Engaging the public with this often-forgotten subject area could increase public support for it and inform policy, ensuring that legislation relating to space weather is based on sound science.

Green aurora over Abisko in Sweden.
Figure 2. Green aurora over Abisko in Sweden. (Credit: Carme Bosch, distributed via imaggeo.egu.eu)

Defining your audience

As with more general astronomy or science outreach, before communicating space weather it is important to define an audience. Will this be a talk at a school or an article for a popular astronomy magazine? Is the aim to brief engineers who work on infrastructure protection or to give evidence to a parliamentary committee? The message needs to be targeted to the public that the communicator is reaching out to.

Communicating with young people or a general audience

When communicating with school children, focussing on the Sun and the fascinating aspects of solar–terrestrial science is a way to get the audience excited rather than scared about space weather. For both younger crowds and the wider public, the use of images, videos, animations and other visuals helps to captivate the audience’s attention and can go a long way towards explaining tricky topics.

A further aid to make the public relate better to space weather is to show them what the Sun looks like at that moment and what the current space weather conditions are. For this, NASA and ESA’s Solar & Heliospheric Observatory (SOHO) page and the US Space Weather Prediction Center website are great resources.

To help familiarise the audience with complex concepts, it is often useful to use everyday analogies and examples — like using a peppercorn and a football to give an idea of the relative sizes of the Earth and Sun. In addition, as with other topics, it is important for the communicator to speak or write clearly and avoid technical terms when reaching out to a general audience.

Bright aurora over Alaska
Figure 3. Bright aurora over Alaska. (Credit: Taro Nakai, distributed via imaggeo.egu.eu)

Communicating with technical audiences and policy makers

The language can be more technical when communicating with engineers or policy makers, but should still be free of discipline-specific jargon. Engineers are likely interested in finding out about the properties of solar storms and how spacecraft can be made more resilient, or how the effects of geomagnetic storms could be mitigated to avoid excessive damage to technological infrastructure.

Policy makers want the facts given in a balanced, clear and objective way, and are interested in space weather aspects with policy relevance, such as monitoring, resilience and funding.

Real-world examples and avoiding scaremongering

A crucial aspect is to strike a balance between informing about the dangers of space weather and avoiding scaremongering. The communicator should give concrete examples about past events that have affected human activity. Typical examples include the famous 1859 Carrington event, which affected telegraph systems and caused aurorae as far south as Cuba (Bell, 2008); the Quebec 1989 geomagnetic storm that caused a power blackout affecting several million people and temporarily paralysed the Montreal metro and international airport (POST Note, 2010); or the Halloween storms of 2003 over northern Europe that damaged satellites, caused a blackout in Sweden, and forced air companies to reroute trans-polar flights (POST Note, 2010).

These events illustrate that space weather is something that the public and policy makers need to be aware of because it can affect their daily lives. But it’s also important to explain that geomagnetic storms, particularly severe ones that could cause trillions of euros in damage, are not very common (Workshop report, 2008). It is important to raise awareness of space weather and educate the public on the best ways to prepare for and mitigate space weather without getting people needlessly worried about its impact. Always finish on a positive note when doing space weather

Getting involved as a science communicator, scientist or member of the public

For those convinced about the importance of engaging the public with space weather, and confident about delivering a targeted and informative message, there are many opportunities to get involved in space weather outreach.

If you are an astronomy communicator, and thus likely to already be writing popular science articles or giving presentations about various aspects of astronomy, why not choose space weather as your next topic?

As a researcher, there are science cafes available to bring space weather to the public, you could blog about your work, give talks at local schools, or — if you are preparing a new and exciting paper on the topic — you can reach out to journalists through the press office at your institution.

Experienced scientists have an additional responsibility to communicate with policy makers. They can reach this audience by providing input to a policy briefing, such as those written by the Parliamentary Office of Science and Technology (POST) in the UK, or by contributing to a governmental report through their research council. Scientists can also apply to serve as science advisers to their local politician or to a governmental body, or join science policy groups in their country to raise the importance of space weather in the political agenda.

Finally, if you are a member of the public who knows little about space weather, but is interested in finding out more, you can help researchers and communicators in this area by taking part in public consultations, such as the Space Weather Public Dialogue underway (at the time of writing) in the UK, which is open to people from all countries. The aim of this project is to help UK research councils and entities find out more about how to best communicate space weather and its impacts and to evaluate the public’s level of preparedness.

If you want to communicate space weather, or help others do it more effectively, there are plenty of opportunities out there to get involved. Be enthusiastic and pro-active, and encourage others to raise public awareness about what happens on the Sun and in our local space environment.

# # #


This article is based on a presentation given at a session of the European Geosciences Union 2014 General Assembly in Vienna on 2 May 2014. The session, titled ‘Raising and Maintaining Awareness of our Local Space Weather: Education and public outreach’, was convened by Athanasios Papaioannou and Jean Lilensten. I am grateful to Athanasios for inviting me to speak at the European Geosciences Union conference, for encouraging me to write this article, and for the useful comments that improved the initial draft of this text.


Bell, T. E & Phillips, T. 2008, A Super Solar Flare: http://science.nasa.gov/science-news/science-at-nasa/2008/06may_carringtonflare/
POST Note 361, 2010, Parliamentary Office of Science and Technology: http://www.parliament.uk/briefing-papers/POST-PN-361.pdf
Riley, P. 2012, Space Weather, 10, 2: http://onlinelibrary.wiley.com/doi/10.1029/2011SW000734/abstract
Workshop report, 2008, Severe space weather events—understanding societal and economic impacts (The National Academies Press: New York): http://www.nap.edu/catalog/12507/severe-space-weather-events–understanding-societal-and-economic-impacts


This article was originally published on the December 2014 issue of the Communicating Astronomy with the Public (CAP) Journal. Head over to the CAP website to download it in PDF format, or read the full issue.   



How curbing HFC emissions could reduce warming

This post is a bit more technical than usual as it was originally written for publication in GeoLog, the blog of the European Geosciences Union (original here). Feel free to ask questions if there’s something that isn’t clear!

Carbon dioxide is without a doubt the most famous of warming culprits. But would reducing emissions of this greenhouse gas be enough to mitigate climate change within this century? A recent paper published in Atmospheric Chemistry and Physics focuses on a less known substance that, if phased out, could avoid as much as 0.5 °C of warming by 2100.

Hydroflurocarbons (HFCs) have an interesting history. Now used widely as refrigerants, propellants, in fire extinguishers and air conditioning, among others, these man-made chemicals became commercially available only some two decades ago. With the adoption of the Montreal Protocol in the late 80s, ozone-depleting substances such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) have been phased out and replaced by ozone-friendly chemicals such as HFCs. But while they don’t damage the ozone layer, HFCs – like their predecessors – have a very high global warming potential: 100-3000 times that of carbon dioxide.

Ozone hole over Antarctica in September 2006, the largest ever recorded. Even though the atmospheric concentrations of CFCs and HCFCs have been decreasing since around 1995 – being replaced by HFCs – their effects are still being felt given the relatively long lifetimes of these ozone-depleting substances. The ozone layer will eventually recover, but the increasing concentrations of HFCs in the atmosphere could exacerbate global warming. (Credit: NASA)
Ozone hole over Antarctica in September 2006, the largest ever recorded. Even though the atmospheric concentrations of CFCs and HCFCs have been decreasing since around 1995 – being replaced by HFCs – their effects are still being felt given the relatively long lifetimes of these ozone-depleting substances. The ozone layer will eventually recover, but the increasing concentrations of HFCs in the atmosphere could exacerbate global warming. (Credit: NASA)

The atmospheric concentration of HFCs is, however, low, accounting for only about 2% of all greenhouse gases. But as nations continue to reduce the use of ozone-depleting substances and with sales of air conditioning and refrigeration equipment booming, particularly in warm, developing countries, the use of HFCs is set to surge. “HFCs are the fastest growing greenhouse gases in the US, where emissions grew nearly 9% between 2009 and 2010 compared to 3.6% for CO2. Globally, HFC emissions are growing 10 to 15% per year and are expected to double by 2020,” the authors write in the new paper citing reports from the US Environmental Protection Agency and the World Meteorological Organization.

This potentially large increase in the use of HFCs motivated the researchers from the US and the Netherlands to find out what role HFCs play in mitigating 21st century climate change. Their aim was to determine how much warming could be avoided by replacing HFCs with readily available substitutes with a lower global warming potential (such as HFOs: hydrofluoro-olefins).

“Our calculations show that controlling HFC growth can avoid a significant amount of warming in this century, at least comparable to CO2 mitigation at 2050, and almost 50 % of CO2 mitigation by 2100,” said lead-author Yangyang Xu of the Scripps Institution of Oceanography in a press release.

Using an integrated carbon and radiant energy balance model, the researchers calculated the change in HFC radiative forcing from 2005 to 2100 under various emission scenarios. They also determined the corresponding temperature changes assuming a climate sensitivity of 0.8 °C/(Wm-2).

Model simulated temperature change under various mitigation scenarios that include CO2 and short-lived climate pollutants (BC: black carbon, CH4: methane, HFCs). The business-as-usual case (BAU, red solid line with spread) considers both high and low estimates of future HFC growths. The red-dash and black lines show the cases of CO2 mitigation and full mitigation, respectively, assuming a climate sensitivity of 0.8 °C/(Wm-2). (Image and caption adapted from Xu et al. 2013)
Model simulated temperature change under various mitigation scenarios that include CO2 and short-lived climate pollutants (BC: black carbon, CH4: methane, HFCs). The business-as-usual case (BAU, red solid line with spread) considers both high and low estimates of future HFC growths. The red-dash and black lines show the cases of CO2 mitigation and full mitigation, respectively, assuming a climate sensitivity of 0.8 °C/(Wm-2). (Image and caption adapted from Xu et al. 2013)

Their results (above) show that if only CO2 emissions are curbed, the expected warming by the end of this century is about 3.3 °C. Adding a reduction in black carbon and methane emissions, as well as HFC mitigation, lowers this value by about 1.5 °C. HFC replacement alone accounts for a drop of 0.5 °C, showing that only full mitigation can keep the 2100 temperature below 2 °C.

The study confirms the importance both the US and China are placing on cutting HFCs in their climate plans. The two countries recently agreed on phasing out production and consumption of these gases and replacing them by HFOs.

“The findings of our study provide even greater justification for phasing-down HFCs under the Montreal Protocol. It’s the biggest, fastest and cheapest climate mitigation available to the world today,” said co-author Durwood Zaelke of the Institute for Governance & Sustainable Development in a press release.

While the paper emphasises how significant HFC mitigation is, the authors point out that this should not be seen as an alternative to reducing CO2 emissions. HFCs, black carbon and methane are short-lived climate pollutants that remain in the atmosphere for up to a few decades only; CO2, on the other hand, can remain in the atmosphere for centuries to millennia. Therefore, the authors conclude, “[f]or the longer-term (century and beyond), mitigation of CO2 would be essential for a significant reduction in the warming.”

Xu, Y., Zaelke, D., Velders, G. J. M., and Ramanathan, V.: The role of HFCs in mitigating 21st century climate change, Atmos. Chem. Phys., 13, 6083–6089, 2013

Eating Animals

I’m reading this rather intense book. It’s called Eating Animals and is by Jonathan Safran Foer.

Maybe you’ve read it, it was published in 2009, or maybe you don’t. For the longest time I didn’t want to read it because I know a few people became vegetarian after reading it. I don’t want to be vegetarian.

I have nothing against it but I don’t think it suits me. I like food, I really like food. Almost all sorts of it and, maybe wrongly, I believe that you cannot be someone who truly likes food if you are vegetarian. I know I may be offending a few people here but, think about it, being vegetarian means you don’t eat about 70, 80, 90% (I don’t know for sure) of the dishes out there.

Vegetarian friends tell me that you forget how good meat and fish taste because you take them out of your menu. You make those 30, 20, 10% of food be all the food. And because there are less ingredients you can cook with, you are more imaginative with your cooking — use more spices, more herbs, nuts, anything to try to make vegetarian dishes as diverse as the omnivore diet. I get the point: I do that myself because I rarely eat meat at home and try to be as imaginative with my veggie recipes as possible. But isn’t that a bit like getting a kid a really colorful bird to make them forget about the puppy they can’t have? Maybe I don’t want to forget about my metaphorical puppy, and why can’t I have both the puppy and the bird?

Enters Eating Animals. A friend convinced me that I should read it (despite my ‘fears’, I’d been toying with the idea for a while) by telling me that the author did not write the book intending to convert people to vegetarianism (“I am a new father, eager to learn as much as I can about the meat industry, in an effort to make informed decisions about what to feed my son”), and that he too struggled with the idea of becoming vegetarian (he often mentions his grandmother’s signature dish, chicken with carrots, which he grew up eating). The thing is, I knew what most of it was going to be about: factory farms, animal rights and suffering, environmental issues. I know about all that and I’ve changed my food choices accordingly: I only buy organic meat in the rare occasions I do buy meat and virtually always buy organic (animal and vegetable) produce. And I do trust that organic farming in Germany means a bit more than it does in the US although, admitedly, I’ve never visit a farm in this country… (And, confession number 2, I do often eat meat when I eat out.)

What is interesting about the book, or at least the 25% I’ve read so far, is that it shows both sides of the issue.

Just this morning, I read a section where “the kind of person who finds herself on a stranger’s farm in the middle of the night” writes anonymously about how she goes into factory farms to rescue the poorly treated chickens, turkeys, hogs, you name it, and tries to show what happens inside those farms to the outside world (and it is not pretty).

The book follows with a letter from a factory farmer explaining how farms have had to adapt to the unwillingness of many consumers to pay the ‘fair’ price for their food (I’ve been known to complain about the €7 it costs to buy two drumsticks at my local organic supermarket, but maybe that price reflects how much it costs to raise a chicken in more humane conditions?). There are 7 billion people in the world and emerging economies are becoming more hungry for meat and animal products. “You hear about free-range eggs and grass-fed cattle, and all of that’s good. I think it’s a good direction. But it ain’t gonna feed the world. Never.”

I put the book down after that. The thing is, that farmer is right. I live in a country with a wealthy economy where organic farming is booming. I can afford to pay €7 every time I feel like eating chicken, and I have that choice. But I cannot picture a world where organic farming will feed China’s growing population and demand for meat. So what is the way forward?

Maybe the remaining 75% of the book will provide some sort of answer. I still strongly believe it is not vegetarianism: if you can’t convince someone like me who worries about this sort of stuff to become vegetarian, how will you even begin to convince the rest of the world that they should reduce their meat consumption?

Maybe the remaining 75% of the book will make me change my mind and become vegetarian, rendering my argument invalid.

I still really want to cook beef wellington for Easter Sunday lunch, though.

Agricultural adventures in a foreign country

This week I cooked a couple of meals with home-grown parsley and coriander. My home-grown parsley and coriander. Somehow I managed to place seeds in soil, water them and care for them enough to see them sprout and grow to full-fledged herbs. Those of you growing tomatoes, peppers or courgettes in your backyard may not be impressed with my feat. But you should be. And here’s why.

Saying I’m not a plant person is an understatement. When I turned 15 or 16 (I can’t remember the exact age), my dad gave me for my birthday a bonsai as old as I was then. That tiny tree lived happily for a decade and a half before I laid hands on it. No more than a few months were needed for the bonsai to dwindle and die on my watch despite my best attempts to care for it.

The Sedum spathulifolium, Cape Blanco (a rock plant) that my co-worker Karen placed on my desk last December is now at the threshold of death. “It needs almost no water, you won’t kill it” she said after I told her the plant would likely dry if I was left to take care of it. It did.


I am not declaring a defeat yet, there are still some green leaves in there!

It gets worse. It was not my first attempt to grow parsley and coriander.

In January, with herb seeds and vases in hand, I went to the nearby garden store here in Munich to buy soil. I came home and I carefully planted the seeds as I had been instructed. For weeks, I watered them and waited for them to grow. Nothing.

Thinking February’s cold snap had killed the seeds (or the fact that I forgot to water them several times), I tried to plant again in the Spring. It was only then, on removing the old soil from the vases, that I realized I was moving not earth, but fertilizer! Words cannot describe the putrid smell emanating from those vases. Imagine fertilizer chemicals (or decaying animal and plant matter — I’m not sure if I bought organic or inorganic fertilizer) brewing in water for weeks under a dry top layer concealing the smell. It was foul!

In my defense, I did not know the German word for soil. Only at the second attempt did I plant my seeds in Erde. And this time they did germinate (!) — possibly because of the small amounts of fertilizer still in the vases — and grew into delicate herbs with a delicious smell.

So yes, I victoriously ate my home-grown parsley and coriander this week. And I’m pleased to say I did not get food poisoning.

photo (1).JPG

My herb garden!

What the Portuguese do to codfish

One of my favourite things about Christmas in Portugal is the food. Not only are the desserts rich and tasty (that’s another post) but so is the traditional main course. The quintessential Portuguese dish is codfish, which can be cooked in a 1001 ways according to a popular saying and is present in almost every household on Christmas eve. And it is good!

Portuguese codfish has little resemblance with the cod eaten in other countries, such as that used for Fish & Chips in many English-speaking nations. Unlike with other fish, we do not consume codfish fresh: we salt and dry it. In fact, the Portuguese word for codfish — bacalhau — is used internationally (sometimes with a slightly different spelling, bacalao) precisely to describe dried and salted codfish.

The Portuguese started fishing and producing cod in this way over 500 years ago. The reason to salt it and dry it was that of preservation: before refrigerators were available, other techniques had to be used to make sure the fish was edible when fishermen returned to land. The process turned out to add flavour to the fish, and is used to this day.

Today, the online version of Público, a renowned Portuguese newspaper, features an excellent visualisation that explains what is exactly that Portuguese do to codfish, from when fishermen catch it to when it’s ready to eat, describing how they process it on fishing trawlers and then on land. The infographic has text in Portuguese but you should be able to get the gist of it from the images only. If you’d like to know more, I provide the original transcript and a rough translation at the end of the post. Click on the screenshot below to see the infographic on Público’s website (I can’t seem to embed it on the blog):

Screen shot 2011-12-24 at 3.59.29 PM.png

Infographic A Viagem do Bacalhau, by Ana Rute Martins, Cátia Mendonça, Joaquim Guerreiro and José Alves (Source: Público, requires Adobe Flash Player.)

Original transcript (in Portuguese): Do mar ao prato, a viagem do bacalhau

Nadam em cardume da Terra Nova ao Mar da Noruega. Com 2 anos têm 40 cm; 7 anos 70/80 cm — atingem a idade de procriar; 10 anos 1.5 m. Uma fêmea pode por entre 4 a 9 milhões de ovos em bancos de areia e temperatura entre 4 a 8º.

(Depois de pescado) O troteiro degola o peixe e abre a barriga. As vísceras e as guelras são retiradas, assim como parte da espinha. Sai (do escalador) com o seu formato conhecido e é lavado. Desce para o porão, é coberto de sal. Viaja para a doca: Lisboa, Setúbal, Sines.

Chega à fábrica. É curado em paletes durante um mês e meio a 1 ano a 4 graus. É lavado e seco entre 48 a 120 horas à temperatura máxima de 23ºC. Terá de humidade 47% e 1/3 do peso após ser pescado. Está pronto a consumir!

Translation: From sea to plate, the journey of cod

They swim in shoals from Newfoundland to the Norwegian Sea. At 2 years old they are 40cm; at 7 years 70/80 cm — reach reproductive age; at 10 years 1.5 m. A female can lay between 4 to 9 million eggs in sandbars and temperature from 4 to 8 degrees C.

(After being fished) The fisherman decapitates the fish and opens its belly. Viscera and gills are removed, as so is part of the spine. It comes out (of the fish scaler) with its familiar format and is washed. It goes down to the hold and is covered with salt. Travels to the dock: Lisbon, Setúbal, Sines.

Arrives at the factory. It’s cured in pallets for a month and a half to one year at 4 degrees C. It is washed and dried between 48 to 120 hours at a maximum temperature of 23 degrees C. It will have a moisture content of 47% and 1/3 of the weight when caught. It is ready to eat!

Why are jet streams not good wind energy sources?

Cross post from GeoLog, the EGU Blog.

Commercial airlines know jet streams well. Planes often hitch a ride on these strong, high-altitude atmospheric winds, which blow from west to east, to fly faster, and they are the reason why long-haul easterly flights (such as those between the US and Europe) are quicker than the corresponding westerly journeys.

Scientists are also familiar with these fierce and persistent winds, which occur at altitudes of 7 to 16 kilometres and have velocities from 90 to several hundred kilometres per hour. Some have even suggested we could harvest wind power from jet streams by developing appropriate airborne technology such as large kite-like wind-power generators. A group of researchers from the US and Australia estimated in 2007 that this potential renewable energy source could provide roughly 100 times the global demand of energy.

But research published this week in Earth System Dynamics, a journal of the European Geosciences Union, challenges this assumption. Lee Miller and collaborators from the Max Planck Institute for Biogeochemistry in Jena, Germany, calculated the maximum extractable energy from these streams to be about 200 times less than previously reported. They also warned that extracting wind power in this way can result in significant climate impacts.


Airborne wind-power generators: to remain science fiction? (Source: AlphaGalileo)

The scientists pointed out that the high velocities of jet streams are not the result of a strong power source but are consequence of the near absence of friction high up in the atmosphere, as it is well-known in meteorology. The group shows in their calculations that, in fact, it takes very little power to accelerate and sustain these winds.

“It is this low energy generation rate that ultimately limits the potential use of jet streams as a renewable energy resource,” said Axel Kleidon, the study’s leader, in a press release.

A maximum of 7.5 terawatts (7.5 trillion watts), less than half of the 2010 global energy demand of 17 terawatts, can be extracted from jet streams, they determined. Previous studies arrived at much higher values because they used the wind velocity to estimate wind power, a method the Max-Planck researchers claim is flawed.

As with other weather systems, jet streams are in part caused by the fact that equatorial regions are warmer than the poles, which are less strongly heated by the sun. The differences in temperature and air pressure between these regions drive the atmosphere into motion creating the strong winds. These differences, rather than wind speeds, are what controls how much of the generated wind can be used as an energy resource.

The authors also estimated the climate impacts of extracting energy from jet streams. Wind turbines build up resistance when harvesting energy, which alters the flow of the wind. This disruption can slow down the entire climate system of our planet when substantial amounts of energy are extracted.

If 7.5 terawatts of energy were extracted from jet streams “the atmosphere would generate 40 times less wind energy than what we would gain from the wind turbines,” said Miller in a press release.

“This results in drastic changes in temperature and weather.”

Aurora? That’s space weather for you

It occurred to me I posted a video featuring auroras without writing about the science associated to them. Here’s a recycled post from the old Dinner Party Science that provides a short explanation about northern lights and the events behind them, which start some 150 million kilometres away from the Earth, in the Sun.

An earlier version of this post was published at Dinner Party Science on Blogspot on 15 September 2010.

You’ve probably heard of auroras or northern lights, or are even lucky enough to have seen one of these events. They are proof positive of the existence of some sort of weather in space. The term space weather refers to changes in the near-Earth space environment which are driven by the Sun. On a calm day, only a breeze of radiation and energetic particles — the solar wind — flows from our star. Sometimes particles from this wind stream into the Earth and interact with the gas in the planet’s atmosphere. These interactions release particles of light causing auroras.


A solar storm, aurora from space, and aurora on Earth. Credit: NASA/STEREO

But not all days are calm and the northern lights are by far the least threatening effect of space weather. Trouble starts when our very active star decides to rebel and begins to emit large amounts of energy, not to mention electrically charged material into space. That’s when you get the space weather equivalent of hurricanes.

The Sun is made out of a material called plasma. Plasma is the fourth state of matter: a solid can be heated up to become liquid, a steaming liquid becomes a gas, and a hot enough gas transforms into plasma. This happens because the atoms that form the gas are separated into their constituents, electrons and nuclei. It is of this, electrically charged, material that the Sun is composed of.

In the solar interior, plasma is in constant motion. If you recall your physics lessons from high school you may remember that moving electric charges generate magnetic fields. In fact, the Sun is a ball of plasma with tangled magnetic field lines breaching through its surface. One of the interesting things about magnetic fields is that they can store a lot of energy. Every now and then the tangled lines of the magnetic field break and the energy they store bursts into space. These explosions are what solar physicists call “solar flares” — the storms of space weather.

It gets worse. Sometimes the magnetic field lines break so violently that they drag along some of the solar plasma. In this case, a coronal mass ejection (CME), the equivalent of a hurricane, occurs. CMEs cause the most damage when they are directed towards the Earth. When they hit, the electrically charged material and energetic particles of the solar wind and solar plasma surge into the Earth’s atmosphere and surface. While this can cause brighter auroras, the more beautiful northern lights come at a price. The radiation associated with CMEs can be harmful to astronauts, and even to airline crews and passengers. CMEs can also affect satellites, interfere with communications and cause power blackouts.

Fortunately, these situations are rare — most days are calm when it comes to space weather. Terrestrial storms and hurricanes are much more likely to cause damage than solar flares and CMEs.

But the weather can always affect you. Even if it’s in space.