Tuesday, 6 March 2012

End is Nigh? Solar Storms - The Threat to Planet Earth #Horizon

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Britain could face widespread power blackouts and be left without critical communication signals, after the earth is hit by a once-in-a-generation “space storm”, Nasa has warned - Telegraph March 2012

(Solar Flare - Image: Nasa) 

Solar Storms - The Threat to Planet Earth
Horizon, BBC2, Tuesday 6th March, 9pm

This year we have a new sort of weather to worry about: and it comes from our nearest star. Scientists are expecting a fit of violent activity on the sun which will propel billions of tonnes of superheated gas and pulses of energy towards our planet - a coronal mass ejection. These ejections will unleash a shockwave of energy, a 'solar storm', into the earth at speeds of over a million miles per hour. Fortunately we won't feel it ourselves, but the earth's magnetic field will. The result could be both beautiful and chaotic.

A severe solar storm can create havoc by damaging communications systems such as those used in air traffic control and the emergency services, and even everyday electronic devices like computers and mobile phones. On March 13, 1989 a severe solar storm caused the collapse of the Hydro-Qu├ębec power grid. Six million people were left without power for nine hours. But all was not lost - one of the planets most spectacular displays, the aurora borealis, was witnessed as far south as Texas.

Usually this light spectacle is restricted to polar regions, stimulated by frequent low level 'solar winds' that hit the Earth on a daily basis. As the electrons from the sun bombard the earth's upper atmosphere, they strike atoms of nitrogen and oxygen and in the process emit light - the aurora borealis, and aurora australis in the South.

The big solar storms that are predicted for 2012 will supercharge the auroras making them brighter and more colourful than ever. So when the TV fizzles out, and the world begins to collapse, don't despair. Grab a beer and sit back in awe to watch a light show that will make Vegas look like Blackpool!

While you wait for that, tune in to Horizon tonight and meet the space weathermen who are trying to predict what's coming our way.


Horizon Produced and Directed by – Ben Fox Series Editor – Aidan Laverty 

Solar Flares & Coronal Mass Ejections

This composite image demonstrates an intense Coronal Mass Ejection (CME) (SOHO/EIT/LASCO)

In this picture, the Sun's surface is quite dark. It shows coronal loops lofted over a solar active region. Glowing brightly in extreme ultraviolet light, the hot plasma entrained above the Sun along arching magnetic fields is cooling and raining back down on the solar surface. (Nasa) 

The Storm Hits Earth

 The arc of light heading towards the earth is a coronal mass ejection, which impacts the earth's magnetic field (shown in purple), causing magnetic storms (USGS) 

Aurora Australis south of Australia as seen from the international space station (Nasa)

4 comments:

  1. Dear BBC Horizon makers
    Can you make two versions of your show please? I really want to knw what the show has to say but I don't have an hour free often enough to watch all the programme. Can you make a second version that concentrates on the words and scientific content only? I think that would result in a marvelous 15 minute episode.

    Many thanks.
    Simon Anthony

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  2. I doubt that the science in this programme would fill 15 minutes. My wife (a maths teacher) and I (an engineer) gave up after about 20 minutes of mostly irrelevant images and ponderous, doom-laden commentary that was completely lacking in detail, or just plain wrong: it is fairly obvious that sunspots do not 'cause' solar storms any more than spots on humans cause measles - they are just a symptom. Most irritating of all, images were presented without any hint of whether they were real, enhanced or simulated, and whether they were real-time or speeded-up.
    Someone once suggested that BBC4 makes interesting, content-rich programmes because they have to: they don't have the budget for all the distracting flashy stuff. Perhaps Horizon's budget should be slashed so that we can get a bit more content.
    Not Horizon's finest hour.
    Adrian Russell

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  3. Oh dear, what is it with Horizon and scientists looking at the sky in the Californain desert? Cheap footage I guess. This was a typical example of the programme's focus on style over content that has plagued the venerable series for a long while now.

    The piece on the Wisconsin-Madison dynamo experiment was obviously considered too boring so that we had to have CGI graphics superimposed over the sphere to suggest it was filling the room with artificial solar flares. The camera jittered as ominous noises appeared to suggest a star had been born. I'm surprised the makers didn't just go whole hog and had the operators announce that they had 'activated the stellar core!' before the cameras tilted wildly as the people lurched from side to side and sparks spewed from the control panel. 'We canna hold it! She's gonna blow!'

    Is it just me or is all this just a tad patronising to the viewers? Slash Horizon's budget to fund BBC4? Yes please and if Horizon carries on making programmes like this then it's time to put it to rest and hand the whole lot over.

    Paul Harris

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  4. I have seen about half of the 6th March podcast. It was enough to make me write the following:

    What I have seen makes me despair about the knowledge that some sun observers have about basic electricity and magnetism. It seems that because magnetism in and on the sun is relatively easy to detect it is assumed to be the cause of most solar phenomena.

    I suggest that sun watchers start with what can't be seen.
    The ionisation around the Earth is caused by the solar wind. It is detectable as positively charged particles but is invisible in the visible and infra red parts of the spectrum.
    The solar wind is so transparent that it causes no obstruction to vision when viewed through 93 million miles of it.

    It has long been known that the strength of the solar wind is more or less proportional to the number of sunspots visible on the sun's surface. It must therefore be concluded that sunspots are a major source of the solar wind.

    We have recently experienced a coronal mass ejection or some other sort of solar flare. The particles leaving the sun in the Earth's direction are no more visible than the solar wind. The energy needed to launch these particles is unknown but enormous. We know that the sun currently produces its energy by the fusion of hydrogen into helium, liberating enormous amounts of heat.

    Heat can't generate magnetism. I started playing with electricity and magnetism when I was 8. I am now 75. The main action of heat on a fluid is to cause convection. In the case of the sun the temperature is so high that the atoms in the fluid have become ionised. In other words they have lost their outer electrons. We also know that a photon is emitted from an atom when it falls from a higher energy level to a lower one. When the temperature is high enough, as is often the case in the sun, many or most atoms will have lost their outer electron shells entirely. The result of this is that such atoms are unable to emit photons. I cannot prove this but I postulate that the temperatures reached in the "dark" interiors of sunspots are so high that only a minority of atoms is able to emit any photons at all. The deficiency of photons caused by this heat is the reason why sunspots appear to be relatively dark.
    I hope that I have established that sunspots are one means by which the sun releases some of its internal energy. We know that the solar wind is stronger when more sunspots are visible. That means that the sunspots are launch sites for some of the solar wind. The particles thus launched must exceed the speed of escape from the sun. This in turn indicates that a massive amount of energy is expended to launch the particles. The enormously high launch energy and the apparent coolness of sunspots due to lack of photons at extremely high temperatures appear to form some sort of match.

    You may note that I have not said much about magnetism so far. This is because I think that the magnetism detected around sunspots is caused by the currents of ionised particles launched from sunspots. Moving ionised particles are an electric current in the same way as electrons flowing through a wire. A wire that has electrons flowing through it has a magnetic field around it. The particles emitted from sunspots are no more visible than the solar wind. There are, as many NASA photographs and films show, a lot of smaller ejections of cooler material all over the sun's apparent surface. These generally fall back to the sun, As they are cooler, the atoms in these ejections can emit some photons, making them visible.
    I think that sun observers have assumed that magnetism is responsible for many of the sun's phenomena because it is so easily detected while the actual cause of the magnetism is ignored because, like the solar wind, it is made up of invisible ejections of highly ionised matter.

    Until otherwise proven, I will always assume that all magnetism is a property of an electric current

    Wilf James BSc.

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