The reason I am talking to you today is to add my voice to those who want immediate action on the key challenges that face our global community. I hope that in 2015, people with power can show creativity, courage, and leadership. Let them rise to the challenge of the sustainable development goals and act not out of self-interest but of common interest. I am very aware of the preciousness of time. See the moment. Act now. I have spent my life traveling across the universe, inside my mind. Through theoretical physics, I have sought to answer some of the great questions. But there are other challenges, other big questions which must be answered, and these will also need a new generation who are interested, engaged, and with an understanding of science. How will we feed an ever-growing population?  I hope that science and technology will provide the answers to these questions, but it will take people, human beings with knowledge and understanding to implement these solutions. One of the great revelations of the Space Age has been the perspective it has given humanity on ourselves. When we see the Earth from space, we see ourselves as a whole. We see the unity and not the divisions. It is such a simple image. With a compelling message, one planet, one human race. We are here together, and we need to live together with tolerance and respect. We must become global citizens. Our only boundaries are the way we see ourselves, the only borders, the way we see each other. I have been enormously privileged, through my work, to be able to contribute to our understanding of the universe. But it would be an empty universe indeed, if it were not for the people I love and who love me. Without them, the wonder of it all would be lost on me. Let us fight for every woman and every man, to have the opportunity to live healthy, make your lives full of opportunity and love. We are all time travelers, journeying together into the future. But let us work together to make that future a place we want to visit. Be brave, be determined, overcome the odds. It can be done.