99% of the universe and other plasma facts – video
By ucjtlmv, on 8 June 2011
Did you know that 99% of the known universe is made up of plasma? This fact was only one of the surprising and thought-provoking facts revealed in Exploring the Plasma Universe at the Cheltenham Science Festival yesterday. Flanked by some exciting experiments involving fire and the simulation of lightning, Kate Lancaster, Melanie Windridge and UCL researcher Lucie Green explained the physics behind plasma, including how it might be used to power spacecraft and provide energy, as well as future directions in plasma research.
But what is plasma? Good question. I have to admit, my first thought on seeing the title of the talk was blood plasma and none too irrelevantly either – it is sometimes thought that this substance was named after blood plasma. Plasma is a state of matter produced by heating a gas until some of the particles are ionised. The molecular bonds break apart into atoms and you are left with a matter containing positive ions and negative electrons. It conducts electricity thanks to the charged atoms which respond to electromagnetic fields, and produces photons, which creates the iconic flashes of colour that you see in lightning, plasma television screens and plasma lamps.
Watch Dr Lucie Green in action at the festival (2 minutes)
So what can we use it for? Firstly, the prevalence of plasma in the universe and the light that it may give off can help us work out the age and movement of galaxies over time and the conditions of the universe during the Big Bang. Secondly, plasma may be used to propel rockets, for example to send spacecraft to the sun, as is planned in the 2013 Solar Orbiter mission. Finally, plasma may be used in nuclear fusion to produce vast amounts of energy that could be used for electricity on Earth.
Not only did this talk lend a great insight into all things plasma, a few other interesting points were raised about how the changing universe may affect us. It is estimated that there has been increased solar activity during the space age due to the eruption of plasma parcels, which is not unusual, but has the potential to affect satellite navigation systems, striking terror into the hearts of anxious drivers everywhere!
Some other useful applications of plasma research were also discussed including the use of plasma in medicine, for example by facilitating more effective X-ray machines, and the possibility of building hybrid nuclear reactors somewhere between fusion and fission which could provide a solution to the problem of nuclear waste. In fact, despite some sound theoretical advances, we are far from being able to unlock the full potential of plasma due to engineering constraints (reactors built to hold plasma need to be able to withstand enormously high temperatures and magnetism).
At the end of the talk, one niggling question remained. Why, if most of the known universe is made up of plasma, is the Earth relatively plasma free? Well, firstly, the extent of the known universe is thought to be about 5% of the whole. Secondly, humans could not survive in plasma conditions since it causes cell damage and radiation sickness. So it seems plasma is thrilling both in its danger and its potential to solve some of our most important energy issues – definitely research to keep an eye on! You can follow UCL’s Solar and Stellar News group and keep up with Lucie Green’s research here.