The understanding of the origin and occurrence of life in the universe will be one of the primary scientific investigations in the 21st century. What is life? One definition, which is of sufficient generality for application to the possible multitude of incarnations of life in the universe, is that life is a self-replicating system capable of change. Life may have originated on Earth or it may have come from other sites in our solar system. For example, there is a real possibility that life came from Mars or Europa. Large impacters on Mars may have launched Martian life into space and some of this life eventually landed on the earth and seeded life here. Exploration of Mars and Europa may result in the discovery of life, or the remnants of life, on those bodies. Such discoveries could result in a major advance in the understanding the origins of life. The recent discovery of planets outside our solar system provides strong support for the possibility of life elsewhere in the Universe. The search for extra solar planets will be a major research effort in the next 100 years. The discovery of life elsewhere than on the Earth will provide important insight into the significance of life on Earth.