30 November 2022
“It was fascinating to see how the things we do in class could be applied in the real world,” remarked one student about the Physics in Action conference in London on Monday 21 November, where Lower Sixth physicists enjoyed talks from some of the brightest minds in the field of physics. Topics covered included “Is it possible to live a carbon-zero life?” and “Fusion energy: how to build a star in a doughnut”. They all took a great deal away from the day, as students’ thoughts on a favourite lecture of the day make clear.
Cherry L – The first stars: unveiling the first billion years of our Universe
Dr Emma Chapman gave us an incredible insight into the world of cosmology, with her passion for discovering the history of the universe - the empty historical gap between the Big Bang and the present. She talked about radio telescopes she is currently working on, which can be used to gather light from the first stars, and taught us how to identify the age of stars by observing the light emitted from the star and the magnification and distortion of the star. Dr Chapman also explained stellar fusion process in a very clear way, solidifying our current understanding of cosmology from our GCSE studies. This was a wonderful and insightful lecture.
Sophie W - Is it possible to live a carbon-zero life?
Dr Michael de Podesta spoke with passion about climate change and the physics behind why carbon dioxide causes heat absorption in the atmosphere. He explained how our heat output from earth is two watts/metre squared, which is equivalent to six atomic bombs continually exploding every second, and talked about how we can reduce our emissions with solar panels, heat pumps and batteries. Finally, Dr de Podesta warned us that the earth will be the ‘coldest’ it will ever be, and although it isn’t yet possible to live a carbon zero life, in the long term it is easy and cheap to reduce our emissions.
Fusion Energy: How to Build a Star in a Doughnut
My favourite lecture was about fusion energy by project engineer Leah Morgan. She explained that using the model of E=mc^2, we can acquire power by combining particles, meaning less reliance on the fossil fuels that produce harmful emissions, bringing us closer to a carbon-free life. This technology, however, is still in its early developmental stages. Despite research and advancements, there are many unsolved problems, such as how to construct an environment that could endure fusion heat.
A new powerful source of energy is in the form of fusion. Fusion is putting two atoms so close together with such a force that they combine into a completely different element. Fusing atoms together releases almost four million times more energy than fossil fuels and four times as much energy as nuclear fission reactions (when having equal mass). At the moment, most nuclear power generation is done through fission (18% of Britain’s energy), but it is still a great matter of concern to those who live near nuclear plants. Fission is dangerous as splitting of the unstable atoms' nuclei can cause radioactivity, which harms the environment and is the source of grave health issues, such as cancer. For these reasons many people have been against the idea of using nuclear power to propel the UK into producing greener energy, despite the energy outcome by nuclear reactions. Fusion solves these problems as it is not dangerous.
Nuclear fusion occurring within a tokamak uses plasma (a substance with a state similar to fire: a charged gas) from deuterium, hydrogen molecules from sea water and tritium, a Canadian company's waste product. These reactions happen at a temperature approximately 100 times hotter than the sun. Because this would instantly melt any metal on Earth, it is contained in a doughnut tokamak and held together by magnets, which prevent plasma from touching the walls and melting everything.
To conclude, nuclear energy by fusion is very new. A lot more research must be done to introduce this on a global scale to make our world greener.
Hannah S - Shining new light on old fossils
I found the lecture by paleobiologist Victoria Egerton extremely interesting. She and her team at the University of Manchester have used a giant laser at multiple sites, including a diamond light source in Didcot, UK, to analyse the elements in a fossil. This element and chemical map can be used to understand the molecular structure of animals and plants to gain knowledge about both historical events millions of years ago and current issues. For example, analysing a fossilised prehistoric bird led to the discovery of copper in its feathers. Further EXAFS analysis indicated that the copper was organically bound in eumelanin, and FITR shows a strong affinity between eumelanin and copper. This is important because melanoma cancer researchers were previously unaware of the presence of copper in the eumelanin model, and this discovery using paleobiology allowed them to update their research and hopefully further their work towards finding a cure for this form of cancer.
Victoria Egerton also explained how paleobiology is used to pinpoint when mass extinction events occurred, including, most recently, a 10-15 km wide meteorite colliding with Earth, which led to the extinction of many dinosaurs. After the meteorite hit, rocks were vapourised and forced into the air, creating a giant ash cloud, which prevented a lot of sunlight reaching Earth, leading to a decrease in photosynthesis and the mass death of plants. This resulted in the mass extinction of herbivores, followed by carnivores, as their food sources dried up. The cloud created a sediment layer of ash, above which is a layer of fossilised fern, which indicates a fern spike. Ferns are one of the most hardy and adaptable plants, so, after a large proportion of their competition was eliminated, they flourished, leading to a fern spike. So, fern spikes are indicators of mass extinction events.
Paleobiologists use this information and other scientific methods to calculate when the extinction events occurred. One method was the discovery of fossilised pebble fish. Pebble fish swim with their mouths open to filter water through their gills, sifting food from the water. These fossils contain microtektites in their gills, which show that these pebble fish must have been alive after the meteorite hit earth 66 million years ago because the microtektites must have fallen from the ash cloud into the water before being sifted through their gills. The fish were only one year old at most when they died, and they died in a period when they were growing. As they are still around today, we know that pebble fish only grow in the spring and summer, therefore the meteorite must have hit in the spring/summer period of that year. A lot of animals use the spring and summer to gain strength and weight so had the meteorite hit later in the year the animals may have been better prepared and perhaps more of them would have survived.