Speakers: Stephen Hawking – Physicist with University of Cambridge, known for the book “a brief history of time”. http://en.wikipedia.org/wiki/Stephen_Hawking
Until 1920s, people thought universe was static and unchanging. We then discovered that distant galaxies were moving away from us, which suggested originally everything was extremely close before expanding, hinting at a big bang. We have made progress understanding Maxwell’s equation and general relativity to understand how the universe has evolved, but struggled to describe the initial state of the universe. Under certain conditions, general relativity allows time to behave as another dimension, removing the distinction between time and space and allowing the universe to spontaneously create itself from nothing. We can use probability to simulate a number of different initial states which agree with observations. In this way, we have solved the creation of the universe.
Looking at extraterrestrial life, we believe life appeared spontaneously on Earth so it should be able to appear elsewhere. Algae fossils imply that life appeared on Earth within half a billion years of it becoming possible, which is short in the earth’s history. This implies that life can form relatively easily, but on the flipside we have not seen any aliens. From searches such as SETI, we can imply that there are no civilisations of our level of development within a few hundred light years.
Looking at the future, if we are the only intelligent beings in the galaxy we should ensure we survive and continue. But we are in a dangerous phase of history – our consumption of finite resources is increasing exponentially, as is our ability to change the world for good or evil. Our genetic code still carries selfish and aggressive instincts that may steer us astray. It will be difficult to deal with these problems to survive 100 years, not to mention thousands or millions. To ensure our survival beyond a hundred years we must expand into space. Stephen was later asked if he believes we are the only civilisation in the Milky Way at our intelligence level. He responds (after 7 minutes to compose the speech, edited out of the video) that he believes this is true, we would have found them otherwise. The other possibility is that our civilisation is in a late phase, and previous races of our technology level have not lasted long before destroying themselves.
Throughout his life, Hawking has tried to answer these 3 questions. He is grateful his disability has not prevented this, and it has given him more time to answer these questions.