ARE WE STAR DUST OR NUCLEAR WASTE?
Dr Robin Catchpole, Institute of Astronomy, Cambridge, United Kingdom
Monday 20–Wednesday 22 January 11.15 am COURSE FEES R330; Staff and students R165
Everything around us, apart from hydrogen and helium, was made inside stars. The Earth and Sun contain elements made in the many generations of stars that were born and died during the nine thousand million years before our Sun and planets were born. The story of the birth and death of stars is the story of the battle of matter against the force of gravity: a battle that gravity wins with either a whimper or a bang.
While stars shine, powered by nuclear fusion, the energy they release maintains the temperature that creates the pressure that holds the force of gravity at bay. Eventually the fuel runs out and gravity takes over, ending their lives. Low mass stars live long and fade away. High mass stars shine bright and live short lives that end with an explosion called a supernova that can outshine the hundred thousand million stars in its host galaxy. In these ways both high and low mass stars return the different proportions of elements they have made to interstellar space, ready to form new stars.
Some stars are so close to each other that they exchange material and even merge, complicating their evolution. When this happens a fading low mass star can be reawakened and explode. Or the merger of two neutron stars, themselves remnants of previous supernovae, may merge and explode, creating most of our gold.
In this course we will follow the story from when the Universe was a few seconds old to the present day and see how we know what we know.
Lecture titles
- Light the messenger: the first stars, Sun-like stars, the fate of the Earth
- Massive stars: how and why they explode
- Multiple stars, many fates
Recommended reading
Rees, M. 2014. Just Six Numbers. Phoenix: Orion Pub Group
Rees, M. 2018. Our Cosmic Habitat. Princeton: Princeton University Press.
Rees, M.J. 2002. Before the Beginning: Our Universe and Others. United Kingdom: Free Press.
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