Professor Henry Snaith FRS explores how human civilisation is truly dependent on the Sun.

View of the Earth's atmosphere from space

The Sun is the source of all life on Earth. Multiple forms of energy are emitted from the Sun, including light, heat and ultraviolet radiation that are all received by the Earth. The energy from the Sun is used to drive numerous processes on Earth such as photosynthesis in plants; this is the process by which plants use sunlight to generate energy and oxygen. Essentially, nothing is more important to our survival on Earth than the Sun. Join us to explore how human civilisation is truly dependent on the Sun at the Royal Society Kavli Medal and Lecture, delivered by Professor Henry Snaith FRS on 26 April.

The Sun is estimated to be around 4.5 billion years old. During this time it has been the main energy source for all life on Earth and is responsible for the generation of our primary energy supply, fossil fuels. These ancient fuels have been an essential factor for the development of human civilisation. Coal is the most abundant and geographically dispersed fossil fuel, which is formed by the decay of plants over millions of years. When coal is burned, the photosynthetic energy stored in these decayed plants is released, and can be used to generate electricity. In 2013 around 29% of the world’s electricity was generated using coal. The generation of electricity in this manner is relatively inexpensive, however, it has many harmful consequences for the environment and our health. Coal is a dirty energy source; it releases many toxic gases, such as carbon dioxide and sulphur dioxide, into the atmosphere. These toxic gases are atmospheric pollutants and are responsible for multiple environmental phenomena including acid rain, smog and global warming.

In addition, another major problem with fossil fuels is the fact that they are being used up at an alarming rate. It is currently estimated that our supply of fossil fuels will run out by 2088. Given that fossil fuels take millions of years to form, once the current available deposits have been consumed, there will be none left for future generations. How will we generate electricity in a more sustainable and environmentally-friendly way?

For the last 60 year scientists and engineers have been developing devices, known as photovoltaic cells, which are capable of converting sunlight directly into electricity. Sunlight is essentially energy that travels 93 million miles from the Sun to the Earth, taking approximately eight-and –a-half minutes. When sunlight reaches these photovoltaic cells, which are usually situated on rooftops of buildings, the light energy is absorbed and used to generate an electrical current. The creation of electricity using this method is renewable, safe and efficient. According to the National Renewable Energy Laboratory, the sunlight received by the Earth in one hour is sufficient enough to meet our annual energy needs worldwide. It is for this reason that the solar energy industry is a rapidly growing market.

At the forefront of how we can make photovoltaic cells an affordable reality, is the Royal Society Kavli Medal 2017 winner Professor Henry Snaith FRS. His research at the University of Oxford focuses on enhancing the physics and technology behind developing low cost photovoltaic devices. Join Professor Snaith at the Kavli Medal and Lecture on 26 April to explore Photovoltaic solar energy: from the photoelectric effect to global power generation and beyond.


  • Reisha Simmonds

    Reisha Simmonds