Introduction to Astronomy February 2021

Dark Energy and the Acceleration of the Universe

by guest speaker Jonathan Park

Early in the 20th century, the consensus was that the Milky Way was the whole universe and that the universe was static (neither expanding nor contracting). By 1931, it had been established that the Milky Way was only one galaxy of many and that the universe was not static, but expanding. Then, in 1998, a remarkable discovery was made: the universe is not only expanding, but this expansion is speeding up! The best explanation for this is “dark energy” – a mysterious energy which has a repulsive gravity effect and currently makes up over two-thirds of the universe. In this introductory talk, Jonathan will discuss how we know the universe is accelerating, how we know how much dark energy there is in the universe, and what dark energy might be. The discussion will finish with two possible scenarios for the end of the universe.

This is a fascinating and hot topic of cosmology and one not to be missed. We look forward to seeing you all there.