Abstract

Gravity has been tested over many years in the lab and the solar system. Small deviations from Newton theory can be explained by Einstein general relativity. The modern theory of gravity has passed all tests in the solar system. However beyond the solar system there have been results over the years suggesting we may have missed something and the Universe might be undergoing a period of accelerated expansion today, possibly explained by a so-called Cosmolgical Constant. I will discuss how we can test gravity and search for deviations from the usual theory. I will show the effect the ‘cosmological constant’ has on the dynamics of the local group of galaxies and how we can search for ‘modified gravity’ using the Sun. Knowledge of general relativity is definitely not required.