1805 THE DARK UNIVERSE
Dr Kurt van der Heyden, senior lecturer, Department of Astronomy, University of Cape Town
As the complexities of nature are explored and understood, new frontiers for exploration are revealed. The planets, stars and everything that can be seen account for a mere five per cent of the Universe. Most of the cosmos is the dark universe: a mix of dark matter and dark energy, both of which remained unsolved puzzles.
The existence of dark matter has been inferred from the motion of stars since the 1930s, but its nature is still a mystery. The dark-matter particle posited by the most popular theory has not been shown to exist yet. The search is narrowing and the possibilities are dwindling; physicists may soon have to find alternative explanations.
Dark energy is even more puzzling. The discovery of the accelerating expansion of the Universe in 1998 called for a driving force that essentially acts like anti-gravity. There is much more left to learn about the dark universe, and many teams are hard at work attempting to unravel these mysteries. What is clear is that the Universe will not easily reveal its secrets.
This two-lecture course will explore what we already know and the mysteries we have yet to solve.
1. Shedding light on the unseen matter
2. Dark energy and the expanding Universe