LIGHT AND DARK MATTERS Part 1

The Sunrise Walk

On Saturday 21 November 2015 I spent the day at London’s Tate Modern for a series of walks, talks, events and workshops staged as part of the International Year of Light.  The fact I made this event at all was due to seeing a tweet fly past on my timeline detailing the event a week earlier, but I’ll come back to that.

On 17 November I bagged the last ticket to take the 7.15 am sunrise walk with Dr Lucy Green of the Mullard Space Science Laboratory, UCL’s Department of Space.  In addition I booked the afternoon Tate session entitled ‘Are we darkened by light?’ with Catherine Heymans, Katie Paterson and Dr Marek Kukula chaired by Asif Khan.

In order for me to arrive on time for the sunrise walk I had to rise at 4.00am travelling in from Essex. The journey along the M11 in the clear twilight was uneventful until I reached the brow of the hill by North Weald airfield, where as always I was struck by the dancing array of lights from the skyscrapers of London on the far horizon.  Within 12 miles I knew I would be bathed in megawatts of light.

Having booked a parking spot near London Bridge, it was just a short walk through Borough Market and along Jubilee Walk on the Southbank to reach Tate Modern.  Seems quite early I guess but in fact I ended up with just minutes to spare after a series of spanners in the works including being woken up 3 times during the night, one of which involved disabling our home fire alarm at 3am and another on arrival in London when the entrance to my parking area was blocked by a fire incident truck.  All designed to throw me off kilter I guess but these are the reasons for time management and planning!

It was a bitterly cold morning with a persistent north wind blowing and although I was wrapped up, I had failed to check the wool beanie was inside my trusty flying jacket, so my head was resigned to exposure.  At first I couldn’t manage to raise anyone at the front entrance to the Tate, so I tried the staff entrance and within a minute Dr Lucy appeared in that reception accompanied by two helpers armed with a bag of headphones and receivers.  We then trooped round to the Turbine Hall entrance to wait for the other walkers.

Our first stop along the walk from Southbank was approx. 50 yards along the Millennium Bridge where in the biting wind Dr Lucy had hoped we would see the sunrise; however the UK weather had other plans.  Here Dr Lucy discussed our knowledge of the Sun, it’s dynamic internal convection process, the magnetic field and particularly the ability to recycle turning hydrogen into helium at the core with heavier elements such as carbon, oxygen, neon and iron being formed by stellar nucleosynthesis.  The Earth’s relationship with our Sun being that most of us and it have at some time been formed from these elements when the solar system was born and will continue to do so for another 5-7 billion years, when the Sun recycles again, becomes a red giant followed by a planetary nebula and finally a white dwarf.

A timeline of the Sun’s life (Credit: Smithsonian National Museum of Natural History and the Smithsonian Astrophysical Observatory)

The Evolution of the Sun is a fascinating subject for anyone wishing to explore further please use my orange hyperlinks in this blog, but remember to come back here!  

Our little group bravely moved on across Millennium Bridge to the framed view of St Paul’s Cathedral for the next stop where Dr Lucy discussed further the Sun’s magnetic field, it’s influence on Earth and the rest of the solar system and our first real understanding of that far-reaching process when space travel began in the 1950’s and 1960’s.  We were shown and able to hold a primitive early edition of a radiation detector used aboard aircraft and later developed for space travel.  Had we then not been interrupted by everything mother-nature could possibly throw at us including thick sideways blown blobs of snow, I might have had a nice picture of this object to include here.

We moved onwards towards the Bank of England, stopping just before under an arch by King Street.  Here we shook off the accumulated wet stuff and listened to Dr Lucy talk about the economic impacts of the Sun.  With the advent of electricity and technology in the 20^th century the economic risk factors have increased.   When our nearest star decides to cough large quantities of matter and electromagnetic radiation out during the course of a CME or solar flare with the solar wind, it doesn’t just produce aurorae displays for our pleasure.  The subsequent shockwave of a CME or flare when it reaches the Earth causes our own magnetosphere to compress on the day side and stretch further out into space on the night side.  The magnetosphere works to protect us to some degree from solar storms, but there are other initially invisible reactions at work.

One such solar storm occurring on March 13, 1989 initially caused short wave radio interference with the arrival of x-rays and ultraviolet light ionizing the upper atmosphere, then aurorae recorded as far south as latitude 19° (Grand Cayman) followed by a total blackout for around 9 hours to the province of Quebec, Canada as a result of magnetic field changes giving rise to underground electrical currents that then interacted with the local igneous rock sending the current through power lines to ultra-sensitive transformers.  To avoid further damage to the transformers the grid was taken down.  The cost in damage to Hydro- Québec was circa C$10m with almost 10x that amount to end-users. Across the US within minutes of this solar storm there were over 200 power related network issues.  In space, satellites had electronic issues with some tumbling out of control for a while.  A further solar storm in August that year brought trading on the Toronto Stock market to a halt.  It is easy then to see the economic impact of a major solar storm.

On route to the next stop I discussed briefly with Dr Lucy the differences between now and 200 years ago when the world was not so reliant on the electricity grid for daily life and therefore the subject of solar storms and their impacts were not on the science discussion agenda.  A repeat of the famous Carrington Day event in 1859 would likely disrupt our modern technically built world to such a degree it could take a decade or more to recover from it.  This is why solar studies and monitoring of spaceweather events are so very important to prepare and minimise the risk to infrastructure on Earth.

We carried on walking through the unfailing cold wind towards Walbrook stopping briefly under an archway to listen to the sounds of the sun through our headsets.  I have heard this before but it’s always nice to reacquaint yourself with the unusual.  This video has a small clip at the end of the sounds.

Unfortunately our next stop was blocked at Walbrook Wharf river walk by a 58 minute estimated wait for the crane to finish unloading city waste onto a barge.  A detour was organised to take us across Southwark Bridge to The Globe on the Southbank, our final destination before returning to the Tate.  Here Dr Lucy spent a short while reciting a poem by Simon Barraclough inspired by the Sun and Shakespeare taken from his collection book Sunspots .  It was a very fitting end to our walk and her tweet is shown here on the left.

Sunrise walk ended at the Globe theatre, to read @EssBarraclough's poem inspired by the Sun & Shakespeare pic.twitter.com/bhf88lHyLg

— Lucie Green (@Dr_Lucie) November 21, 2015

Detour of our group walking along Cousins Lane

I think we were all a little relieved to be back in the warm confines of the Tate Modern where we were led up to the 6^th floor for a breakfast of tea, coffee, cake and fruit.  During the walk I had chatted with many others in the group including several artists and these informal chats continued over coffee.  As an amateur astronomer I take a great interest in our Sun and regularly observe sunspots and finer details of our nearest star using safe white light filters and a Hydrogen Alpha eyepiece.  I showed one of these images detailing a solar prominence to a lady artist who was interested and it is reproduced here.

Nice clear curling prominence feature on the Sun's West limb - 8 Oct 2015

My interest in the subject of light and dark extends further to the stars outside our solar system and I have been following one variable star in particular now for a year whilst it displayed increasing light curve variations in the form of a Nova, observing this through the iTelescope network and collecting data myself.  This week I have chosen to ‘adopt’ V5668 Sgr for a year via AAVSO.

I would like to pass a huge thank you to Dr Lucy Green for taking the time to travel into London so early, braving some pretty extreme weather conditions to talk us through one of the most fascinating objects in the Universe, an extremely enjoyable Saturday morning all round.  I’m always looking to learn from such events even with subjects I’m already aware of, there is always more to take on board.